WorldWideScience

Sample records for backfilling

  1. Horizontal roof gap of backfill hydraulic support

    Institute of Scientific and Technical Information of China (English)

    张强; 张吉雄; 邰阳; 方坤; 殷伟

    2015-01-01

    For the backfill hydraulic support as the key equipment for achieving integration of backfilling and coal mining simultaneously in the practical process, its characteristics will directly influence the backfill body’s compression ratio. Horizontal roof gap, as a key parameter of backfilling characteristics, may impact the backfilling effect from the aspects of control of roof subsidence in advance, support stress, backfilling process and the support design. Firstly, the reason why horizontal roof gap exists was analyzed and its definition, causes and connotation were introduced, then adopting the Pro/E 3D simulation software, three typical 3D entity models of backfill hydraulic supports were built, based on the influence of horizontal roof gap on backfilling effect, and influence rules of four factors, i.e. support height, suspension height, suspension angle and tamping angle, were emphatically analyzed on horizontal roof gap. The results indicate that, the four factors all have significant impacts on horizontal roof gap, but show differences in influence trend and degree, showing negative linear correlation, positive linear correlation, positive semi-parabolic correlation and negative semi-parabolic correlation, respectively. Four legs type is the most adaptive to the four factors, while six legs (II) type has the poorest adaptability, and the horizontal roof gap is small under large support height, small suspension height, small suspension angle and large tamping angle situation. By means of optimizing structure components and their positional relation and suspension height of backfill scrape conveyor in the process of support design and through controlling working face deployment, roof subsidence in advance, mining height and backfilling during engineering application, the horizontal roof gap is optimized. The research results can be served as theoretical basis for support design and guidance for backfill support to have better performance in backfilling.

  2. Preparation for YMP backfill activities

    Energy Technology Data Exchange (ETDEWEB)

    Conca, J.

    1998-12-23

    Yucca Mountain activities for FY 1999 are anticipated to require specific information on the chemical and physical properties of the candidate getter materials and other backfill components necessary for defensible modeling of the source term, and possible controlling of the source term. There should be three tasks to this activity: at the end of this report is a draft test plan reflecting the present funding anticipated, the other tasks may be added as funding becomes available. (Task 1) The immobilization capacity of the getter materials for specific radionuclides. This task will primarily include column sorption tests of getter materials with solutions spiked with radionuclides. The getter materials will include Apatite II, MgO (with NaPO{sub 4} plus Ba,SrCO{sub 3} and soluble sulfate, with and without Apatite II), Gibbsite/Boehmite, and Hematite. Radionuclides will include Pu, U, Np, Am, Ra, Tc, and Th. Experiments will be performed under various anticipated repository conditions and with anticipated solution compositions. Occasional batch tests will be used to obtain specific K{sub d}s and other thermodynamic data. Solid and liquid analyses will be needed for characterization of the effluent concentrations from the columns to assess performance and for use in geochemical modeling. (Task 2) Intrinsic stability of the getter materials under repository conditions. The use of any candidate getter material will depend upon its anticipated lifetime in the backfill environment. Literature search for any existing data will be performed and augmented by solubility experiments on the getter materials. This is especially important for the reactive materials such as MgO and the soluble sulfates and phosphates that may be a limited lifetime in the backfill. It is also necessary to decide how much getter material to emplace. (Task 3) Diffusion of radionuclides across a Richards Barrier. The Richards Barrier, if emplaced, will act as a hydraulic diversion barrier for the

  3. Geotechnical considerations in mine backfilling in Australia

    Energy Technology Data Exchange (ETDEWEB)

    N. Sivakugan; R.M. Rankine; K.J. Rankine; K.S. Rankine [James Cook University, Townsville, Qld. (Australia). School of Engineering

    2006-07-01

    Mine backfilling can play a significant role in the overall operation of a mine operation. In the Australian mining industry, where safety is a prime consideration, hydraulic systems are the most common backfills deployed. Many accidents reported at hydraulic fill mines worldwide have mainly been attributed to a lack of understanding of their behaviour and barricade bricks. There are two basic types of backfilling strategies. The first, uncemented backfilling, does not make use of binding agents such as cement, and their characteristics can be studied using soil mechanics theories. A typical example of uncemented backfilling is the use of hydraulic fills that are placed in the form of slurry into the underground voids. The second category, cemented backfilling, makes use of a small percentage of binder such as Portland cement or a blend of Portland cement with another pozzolan such as fly ash, gypsum or blast furnace slag. This paper describes the findings from an extensive laboratory test programme carried out in Australia on more than 20 different hydraulic fills and several barricade bricks. A limited description of paste backfills is also provided, and the usefulness of numerical modelling as an investigative tool is highlighted. 21 refs., 10 figs., 1 tab.

  4. Systematic Selection and Application of Backfill in Underground Mines

    OpenAIRE

    Masniyom, Manoon

    2009-01-01

    The use of backfill in underground mining is increasing due to need for systematic backfilling of mine openings and workings to avoid surface damage, increase safety and contribution to sustainable mining. This study is to investigate backfill materials and new methods suited for systematic selection and application of backfill in underground mines. Laboratory tests were carried out on physical, chemical and mechanical properties of different backfill materials and mixtures thereof. Special a...

  5. Colonization of compacted backfill materials by microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Lucht, L.M.; Stroes-Gascoyne, S.; Miller, S.H.; Hamon, C.J.; Dixon, D.A

    1997-11-01

    Experiments were carried out to investigate the occurrence of pore clogging in backfill by bacterial activity. Four differently prepared and treated backfill materials were used to determine the effects of the quality and preparation method of the backfill materials on the occurrence of pore clogging. The backfills were compacted in permeameters which were infused with either groundwater or sterile distilled water. A constant pressure was applied to increase the rate of saturation. Results showed different inflow rates for the four materials despite the use of the same packing method for each specimen, the same dry density for each backfill and indications of similar initial pore volumes. These differences were likely caused by the fact that the two slowest-flowing permeameters contained a mixture of Na-bentonite and illitic shale simulating a glacial lake clay. Hydraulic conductivities measured ranged from 5 x 10{sup -11} m/s to 5 x 10{sup -12} m/s for the backfills containing glacial lake clay and 4 x 10{sup -12} m/s to 9 s 10{sup -13} m/s for the backfills containing a mixture of Na-bentonite and illitic shale. Weekly samples of outflow from the permeameters were analyzed microbially. Aerobic heterotrophs were low initially but stabilized around 10{sup 6} to 10{sup 7} colony forming units (CFU)/mL after about one week. Anaerobic heterotrophs stabilized at around 10{sup 2} to 10{sup 3} CFU/mL. Sulphate-reducing bacteria (SRB) were measured by the most probable number (MPN) method. Results showed low initial numbers but they stabilized around 10{sup 4} MPN/mL after one to two months. No significant numbers of aerobic or anaerobic sulphur oxidizing bacteria were found. Enumeration of methanogens indicated that they were generally present in the permeameters that contained non-autoclaved backfill. Results are partially inconclusive because of the lack of confirmation of methane gas present in the headspace of part of the MPN culture tubes. Microbial pore clogging

  6. A Historical Review of WIPP Backfill Development

    Energy Technology Data Exchange (ETDEWEB)

    Brush, L.H.; Krumhansl, J.L.; Molecke, M.A.; Papenguth, H.W.

    1999-07-15

    Backfills have been part of Sandia National Laboratories' [Sandia's] Waste Isolation Pilot Plant [WIPP] designs for over twenty years. Historically, backfill research at Sandia has depended heavily on the changing mission of the WIPP facility. Early testing considered heat producing, high level, wastes. Bentonite/sand/salt mixtures were evaluated and studies focused on developing materials that would retard brine ingress, sorb radionuclides, and withstand elevated temperatures. The present-day backfill consists of pure MgO [magnesium oxide] in a pelletized form and is directed at treating the relatively low contamination level, non-heat producing, wastes actually being disposed of in the WIPP. It's introduction was motivated by the need to scavenging CO{sub 2} [carbon dioxide] from decaying organic components in the waste. However, other benefits, such as a substantial desiccating capacity, are also being evaluated. The MgO backfill also fulfills a statutory requirement for assurance measures beyond those needed to demonstrate compliance with the US Environmental Protection Agency [EPA] regulatory release limits. However, even without a backfill, the WIPP repository design still operates within EPA regulatory release limits.

  7. Performance of cemented coal gangue backfill

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qin-li; WANG Xin-min

    2007-01-01

    Possibility of cemented gangue backfill was studied with gangue of Suncun Coal Mine, Xinwen Coal Group, Shandong,and fly ash of nearby thermal power plant, in order to treat enormous coal gangue on a large scale and to recovery safety coal pillars.The results indicate that coal gangue is not an ideal aggregate for pipeline gravity flow backfill, but such disadvantages of gangue as bad fluidity and serious pipe wear can be overcome by addition of fly ash. It is approved that quality indexes such as strength and dewatering ratio and piping feature of slurry can satisfy requirement of cemented backfill if mass ratio of cement to fly ash to gangue higher middle and long term comprehensive strength.

  8. Backfilling of trenches exposed to waves

    DEFF Research Database (Denmark)

    Hjelmager Jensen, Jacob; Fredsøe, Jørgen

    1997-01-01

    -closure. The backfilling process of trenches exposed to either waves or a steady current is of importance in relation to the implementation of pipelines in the marine environment. With respect to the sedimentation of trenches, the non-dimensional Trench-Keulegan-Carpenter number, KC = a/L, where a is the excursion length...... of a particle in waves and L the trench length, is investigated in detail, and an optimal KC-number for the backfilling rate is found. Coherent structures in the non-uniform unsteady trench-flow are shown to dominate the deposition rate when present. The importance of a detailed description of the flow...

  9. Implementation of Paste Backfill Mining Technology in Chinese Coal Mines

    OpenAIRE

    Qingliang Chang; Jianhang Chen; Huaqiang Zhou; Jianbiao Bai

    2014-01-01

    Implementation of clean mining technology at coal mines is crucial to protect the environment and maintain balance among energy resources, consumption, and ecology. After reviewing present coal clean mining technology, we introduce the technology principles and technological process of paste backfill mining in coal mines and discuss the components and features of backfill materials, the constitution of the backfill system, and the backfill process. Specific implementation of this technology a...

  10. Time-dependent nuclide transport through backfill into a fracture

    International Nuclear Information System (INIS)

    This paper presents a transient analysis of radionuclide transport through backfill into a fissure. This report considers a waste canister surrounded by backfill in a borehole intersected by a fracture, in water-saturated rock. Radionuclides are released at a constant concentration C/sub s/ at the waste surface into the backfill. Ground water flows in the fissure. We assume no ground-water flow in the backfill, so that radionuclide transport through the backfill is controlled by molecular diffusion. 3 refs., 2 figs

  11. Experimental Evaluation of Backfill in Scour Holes around Offshore Monopiles

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Frigaard, Peter

    2010-01-01

    have investigated the time scale of erosion in small scale experiments and found a dependency on Shields parameter and the Keulegan-Carpenter number. Further knowledge is however needed in larger scale. Regarding the rate of backfill, further knowledge is needed for both small and large scale....... Currently there is no knowledge concerning the relative density, and hereby also the strength and deformation properties of the backfilled soil material. The strength of the backfilled soil and the time scale of respective erosion and backfilling is of high importance when designing the steel structure...... scale of backfilling is found to be small in comparison with existing small scale experiments....

  12. Assessment of backfill design for KBS-3V repository

    Energy Technology Data Exchange (ETDEWEB)

    Keto, Paula (B+tech, Eurajoki (Finland)); Dixon, David (AECL, Harwell (United Kingdom)); Jonsson, Esther; Gunnarsson, David (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Boergesson, Lennart (Clay Technology AB, Lund (Sweden)); Hansen, Johanna (Posiva (Finland))

    2009-12-15

    Posiva and SKB initiated a joint programme BACLO (Backfilling and Closure of the Deep repository) in 2003 with the aim to develop methods and materials for backfilling of deposition tunnels. This report summarises the work done in the third and final phase of the BACLO programme. The main objective of this phase was to study how the various processes active during backfill installation and saturation as well as technical constraints affect its design basis. The work focused on the performance and technical feasibility of a block backfill concept, which calls for filling the majority of the tunnel volume with pre-compacted backfill blocks and the remaining volume with bentonite pellets. Several backfill composition alternatives were chosen for study and they consisted of clay materials with differing amounts of swelling minerals. A large body of information was gained on the effect of different processes on the performance of these backfill options, e.g. water inflow, piping, erosion, self-healing, homogenisation and interaction between backfill and buffer in various laboratory and small-scale field tests. More practical tests included e.g. studies how the blocks and pellets could be installed to the deposition tunnel. Based on the new information on the effect of the processes investigated and the estimated achievable block filling degree and backfill density, recommendations were made concerning material selection, backfill layout and technical issues. In addition, issues requiring further attention to verify the long-term performance of the proposed backfill concept are identified and listed

  13. Implementation of Paste Backfill Mining Technology in Chinese Coal Mines

    Directory of Open Access Journals (Sweden)

    Qingliang Chang

    2014-01-01

    Full Text Available Implementation of clean mining technology at coal mines is crucial to protect the environment and maintain balance among energy resources, consumption, and ecology. After reviewing present coal clean mining technology, we introduce the technology principles and technological process of paste backfill mining in coal mines and discuss the components and features of backfill materials, the constitution of the backfill system, and the backfill process. Specific implementation of this technology and its application are analyzed for paste backfill mining in Daizhuang Coal Mine; a practical implementation shows that paste backfill mining can improve the safety and excavation rate of coal mining, which can effectively resolve surface subsidence problems caused by underground mining activities, by utilizing solid waste such as coal gangues as a resource. Therefore, paste backfill mining is an effective clean coal mining technology, which has widespread application.

  14. Tunnel backfill erosion by dilute water

    International Nuclear Information System (INIS)

    The goal was to estimate smectite release from tunnel backfill due to dilute groundwater pulse during post glacial conditions. The plan was to apply VTT's two different implementations (BESWD and BESWS) of well-known model of Neretnieks et al. (2009). It appeared difficult to produce repeatable results using this model in COMSOL 4.2 environment, therefore a semi-analytical approximate approach was applied, which enabled to take into account both different geometry and smectite content in tunnel backfill as compared to buffer case. The results are quite similar to buffer results due to the decreasing effect of smaller smectite content and the increasing effect of larger radius. (orig.)

  15. Some characteristics of potential backfill materials

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, D.R.

    1983-05-01

    A backfill material is one of the multiple barriers that may be involved in the disposal of nuclear waste. Such backfill should be a desiccant with the hydrous product having acceptable stability; it should sorb any released radioisotopes, and it should reseal any breached site. The backfill must also have acceptable thermal conductivity. This report presents data on the rate of hydration and the nature of the product of reaction of some candidate backfill materials with water and with brine. Thermal conductivity data is reported for both the reactants and the products. Granular MgO at 150/sup 0/C completely hydrates in less than 10 hours. At 60/sup 0/C and 20/sup 0/C, such extensive hydration requires about 100 and 1000 hours, respectively. The product of the reaction is stable to more than 300/sup 0/C. A doped discalcium silicate was less reactive and the product contains less water of crystallization than the MgO. The reaction product of dicalcium silicate is cementous, but it has low thermal stability. Bentonite readily reacts with water and expands. The reaction product has the properties of vermiculite, which indicates that magnesium ions have diffused into the bentonite structure and are not simply adsorbed on the surface. If bentonite is emplaced in a saline environment, the properties of vermiculite, the reaction product, should also be considered. The thermal conductivity of MgO, discalcium silicate, and bentonite is primarily dependent on the porosity of the sample. A slight increase in thermal conductivity was found with increased temperature, in contrast to most rocks. If the conductive data for the different materials is equated to the same porosity, MgO has the superior thermal conductivity compared to bentonite or discalcium silicate.

  16. Some characteristics of potential backfill materials

    International Nuclear Information System (INIS)

    A backfill material is one of the multiple barriers that may be involved in the disposal of nuclear waste. Such backfill should be a desiccant with the hydrous product having acceptable stability; it should sorb any released radioisotopes, and it should reseal any breached site. The backfill must also have acceptable thermal conductivity. This report presents data on the rate of hydration and the nature of the product of reaction of some candidate backfill materials with water and with brine. Thermal conductivity data is reported for both the reactants and the products. Granular MgO at 1500C completely hydrates in less than 10 hours. At 600C and 200C, such extensive hydration requires about 100 and 1000 hours, respectively. The product of the reaction is stable to more than 3000C. A doped discalcium silicate was less reactive and the product contains less water of crystallization than the MgO. The reaction product of dicalcium silicate is cementous, but it has low thermal stability. Bentonite readily reacts with water and expands. The reaction product has the properties of vermiculite, which indicates that magnesium ions have diffused into the bentonite structure and are not simply adsorbed on the surface. If bentonite is emplaced in a saline environment, the properties of vermiculite, the reaction product, should also be considered. The thermal conductivity of MgO, discalcium silicate, and bentonite is primarily dependent on the porosity of the sample. A slight increase in thermal conductivity was found with increased temperature, in contrast to most rocks. If the conductive data for the different materials is equated to the same porosity, MgO has the superior thermal conductivity compared to bentonite or discalcium silicate

  17. Wormhole Formation in RSRM Nozzle Joint Backfill

    Science.gov (United States)

    Stevens, J.

    2000-01-01

    The RSRM nozzle uses a barrier of RTV rubber upstream of the nozzle O-ring seals. Post flight inspection of the RSRM nozzle continues to reveal occurrence of "wormholes" into the RTV backfill. The term "wormholes", sometimes called "gas paths", indicates a gas flow path not caused by pre-existing voids, but by a little-understood internal failure mode of the material during motor operation. Fundamental understanding of the mechanics of the RSRM nozzle joints during motor operation, nonlinear viscoelastic characterization of the RTV backfill material, identification of the conditions that predispose the RTV to form wormholes, and screening of candidate replacement materials is being pursued by a joint effort between Thiokol Propulsion, NASA, and the Army Propulsion & Structures Directorate at Redstone Arsenal. The performance of the RTV backfill in the joint is controlled by the joint environment. Joint movement, which applies a tension and shear load on the material, coupled with the introduction of high pressure gas in combination create an environment that exceeds the capability of the material to withstand the wormhole effect. Little data exists to evaluate why the material fails under the modeled joint conditions, so an effort to characterize and evaluate the material under these conditions was undertaken. Viscoelastic property data from characterization testing will anchor structural analysis models. Data over a range of temperatures, environmental pressures, and strain rates was used to develop a nonlinear viscoelastic model to predict material performance, develop criteria for replacement materials, and quantify material properties influencing wormhole growth. Three joint simulation analogs were developed to analyze and validate joint thermal barrier (backfill) material performance. Two exploratory tests focus on detection of wormhole failure under specific motor operating conditions. A "validation" test system provides data to "validate" computer models and

  18. Numerical calculation of backfilling of scour holes

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Baykal, Cüneyt; Fuhrman, David R.;

    2014-01-01

    A fully-coupled hydrodynamic and morphologic CFD model is presented for simulating backfilling processes around structures. The hydrodynamic model is based on Reynolds-averaged Navier-Stokes equations, coupled with two-equation k-ω turbulence closure. The sediment transport model consists of sepa...... of structures: piles, and pipelines. Initial scour holes are generated by the same model. The numerical results appear to be in accord with the existing experimental information....

  19. Assessment of the oxygen consumption in the backfill. Geochemical modelling in a saturated backfill

    Energy Technology Data Exchange (ETDEWEB)

    Grandia, Fidel; Domenech, Cristina; Arcos, David; Duro, Lara [Enviros Spain S.L., Barcelona (Spain)

    2006-11-15

    The consumption of oxygen in the deep disposal is a major concern due to the ability of this element to corrode the canisters where high level nuclear wastes (HLNW) are disposed. The anoxic conditions initially present in a deep geologic environment are disturbed by the excavation of the repository facilities. After sealing the deposition holes and tunnels using clay-based materials, oxygen remains dissolved in porewater or as a gas phase in the unsaturated pores. The main mechanisms of oxygen depletion that can be considered in the backfill materials are: (1) diffusion into the surrounding rock and (2) kinetic reactions with accessory minerals and organic matter existing in the backfill. In this report, a set of numerical simulations are carried out in one and two dimensions in order to test the effect on the oxygen concentration in the pore water of all these mechanisms. The backfill considered is a 0/70 mixture of MX-80 bentonite and crushed material from the excavation itself. In addition to organic matter, the solid phases with reducing capacity in the backfill are Fe(II)-bearing minerals: pyrite (FeS{sub 2}) and siderite (FeCO) (as accessory minerals in the bentonite) and Fe-biotite (from the crushed granite). In the simulations, other chemical processes like cation exchange and surface complexation onto clay surfaces, and thermodynamic equilibrium with calcite, gypsum and quartz are considered. Initial composition of porewater is obtained by equilibrating the Forsmark groundwater with the backfill material. The 1D simulation consists of a number of cells with no reactive minerals or organic matter representing granite. The central cell, however, contains oxygen and reactive minerals resembling a backfill. Oxygen is allowed to move only by diffusion. The 2D model simulates the interaction with a backfill of a granitic groundwater flowing through a fracture. Like in the 1D model, the backfill contains oxygen and reactive solids. The results are very similar in

  20. Hydraulic calculation of gravity transportation pipeline system for backfill slurry

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qin-li; HU Guan-yu; WANG Xin-min

    2008-01-01

    Taking cemented coal gangue pipeline transportation system in Suncun Coal Mine, Xinwen Mining Group, Shandong Province, China, as an example, the hydraulic calculation approaches and process about gravity pipeline transportation of backfill slurry were investigated. The results show that the backfill capability of the backfill system should be higher than 74.4m3/h according to the mining production and backfill times in the mine; the minimum velocity (critical velocity) and practical working velocity of the backfill slurry are 1.44 and 3.82m/s, respectively. Various formulae give the maximum ratio of total length to vertical height of pipeline (L/H ratio) of the backfill system of 5.4, and then the reliability and capability of the system can be evaluated.

  1. Backfilling with Fairness and Slack for Parallel Job Scheduling

    International Nuclear Information System (INIS)

    Parallel job scheduling typically combines a basic policy like FCFS with backfilling, i.e. moving jobs to an earlier than their regular scheduling position if they do not delay the jobs ahead in the queue according to the rules of the backfilling approach applied. Commonly used are conservative and easy backfilling which either have worse response times but better predictability or better response times and poor predictability. The paper proposes a relaxation of conservative backfilling by permitting to shift jobs within certain constraints to backfill more jobs and reduce fragmentation and subsequently obtain better response times. At the same time, deviation from fairness is kept low and predictability remains high. The results of the experimentation evaluation show that the goals are met, with response-time performance lying as expected between conservative and easy backfilling.

  2. CLASSIFICATION OF THE MGR BACKFILL EMPLACEMENT SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    R. Garrett

    1999-08-31

    The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) backfill emplacement system structures, systems and components (SSCs) performed by the MGR Safety Assurance Department. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 1998). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998).

  3. 30 CFR 816.105 - Backfilling and grading: Thick overburden.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Backfilling and grading: Thick overburden. 816...-SURFACE MINING ACTIVITIES § 816.105 Backfilling and grading: Thick overburden. (a) Definition. Thick... surrounding terrain. (b) Performance standards. Where thick overburden occurs within the permit area,...

  4. 30 CFR 817.107 - Backfilling and grading: Steep slopes.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Backfilling and grading: Steep slopes. 817.107 Section 817.107 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... ACTIVITIES § 817.107 Backfilling and grading: Steep slopes. (a) Underground mining activities on steep...

  5. 30 CFR 816.107 - Backfilling and grading: Steep slopes.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Backfilling and grading: Steep slopes. 816.107... ACTIVITIES § 816.107 Backfilling and grading: Steep slopes. (a) Surface mining activities on steep slopes... section except where mining is conducted on flat or gently rolling terrain with an occasional steep...

  6. A numerical evaluation of continuous backfilling in cemented paste backfilled stope through an application of wick drains

    Institute of Scientific and Technical Information of China (English)

    Li Li; Yang Pengyu

    2015-01-01

    Cemented paste backfill (CPB) is gaining popularity in many underground mines worldwide. Sufficient water is added into CPB to make a flowable material for pipe transportation. Barricades are built near the drawpoints to prevent in-rush of the fill slurry. To avoid barricade failures resulting from excessive backfill pressures, backfilling is typically performed with a plug pour followed by a final pour. The inter-val between the two pours should be shortened or removed to increase mining productivity and avoid pipe clogging. Recently, Li proposed to apply wick drains in backfilled stopes to promote drainage and consolidation. The preliminary simulations by considering an instantaneous filling indicated that the drainage of CPB can be significantly accelerated by using wick drains. Barricade was not considered. Here, some new numerical modellings are presented with more representative filling sequences, stope geometry, and different draining configurations. The results illustrate that the stope can be backfilled continuously by using wick drains.

  7. Strata movement controlling effect of waste and fly ash backfillings in fully mechanized coal mining with backfilling face

    Institute of Scientific and Technical Information of China (English)

    Zhang Jixiong; Zhang Qiang; Huang Yanli; Liu Jinwei; Zhou Nan; Zan Dongfeng

    2011-01-01

    A fully mechanized coal mining with backfilling (FMCMB) provides advantages of safety and efficiency for coal mining under buildings,railways,and water bodies.According to the field geological conditions,we analyzed the controlling effect of strata movement by the waste and fly ash backfilling in FMCMB face.Based on the key strata theory,we established the equivalent mining thickness model,and analyzed the action of the bulk factor of backfilling body to the equivalent mining thickness.In addition,we numerically simulated the controlling function of the strata movement by backfilling bodies with different strength.And the numerical simulation result show that the deformation of stratum and the subsidence of surface can be controlled by FMCMB.The result provides references to the effective execution of fully mechanized coal mining with solid waste backfilling in goal.

  8. Backfilling and closure of the deep repository. Assessment of backfill concepts

    Energy Technology Data Exchange (ETDEWEB)

    Gunnarsson, David; Boergesson, Lennart [Clay Technology AB, Lund (Sweden); Keto, Paula [Saanio Riekkola Oy (Finland); Tolppanen, Pasi [Jaakko Poeyry Infra (Finland); Hansen, Johanna [Posiva Oy, Helsinki (Finland)

    2004-06-01

    This report presents the results from work made in Phase 1 of the joint SKB-Posiva project 'Backfilling and Closure of the Deep Repository' aiming at selecting and developing materials and techniques for backfilling and closure of a KBS-3 type repository for spent nuclear fuel. The aim of phase 1, performed as a desk study, was to describe the potential of the suggested backfill concepts in terms of meeting SKB and Posiva requirements, select the most promising ones for further investigation, and to describe methods that can be used for determining the performance of the concepts. The backfilling concepts described in this report differ from each other with respect to backfill materials and installation techniques. The concepts studied are the following: Concept A: Compaction of a mixture of bentonite and crushed rock in the tunnel. Concept B: Compaction of natural clay with swelling ability in the tunnel. Concept C: Compaction of non-swelling soil type in the tunnel combined with application of pre-compacted bentonite blocks at the roof. Concept D: Placement of pre-compacted blocks; a number of materials are considered. Concept E: Combination of sections consisting of a) crushed rock compacted in the tunnel and b) pre-compacted bentonite blocks. The bentonite sections are installed regularly above every disposal hole. Concept F: Combination of sections consisting of a) crushed rock compacted in the tunnel and b) pre-compacted bentonite blocks. The distance between the bentonite sections is adapted to the local geology and hydrology.The assessment of the concepts is based on performance requirements set for the backfill in the deposition tunnels for providing a stable and safe environment for the bentonite buffer and canister for the repository service time. In order to do this, the backfill should follow certain guidelines, 'design criteria' concerning compressibility, hydraulic conductivity, swelling ability, long-term stability, effects on

  9. Dedicated heterogeneous node scheduling including backfill scheduling

    Science.gov (United States)

    Wood, Robert R.; Eckert, Philip D.; Hommes, Gregg

    2006-07-25

    A method and system for job backfill scheduling dedicated heterogeneous nodes in a multi-node computing environment. Heterogeneous nodes are grouped into homogeneous node sub-pools. For each sub-pool, a free node schedule (FNS) is created so that the number of to chart the free nodes over time. For each prioritized job, using the FNS of sub-pools having nodes useable by a particular job, to determine the earliest time range (ETR) capable of running the job. Once determined for a particular job, scheduling the job to run in that ETR. If the ETR determined for a lower priority job (LPJ) has a start time earlier than a higher priority job (HPJ), then the LPJ is scheduled in that ETR if it would not disturb the anticipated start times of any HPJ previously scheduled for a future time. Thus, efficient utilization and throughput of such computing environments may be increased by utilizing resources otherwise remaining idle.

  10. Application of paste backfill in underground coal fires

    Energy Technology Data Exchange (ETDEWEB)

    Drebenstedt, C.; Masniyom, M. [Technische Univ., Freiberg (Germany)

    2009-07-01

    Coal fires are common in most coalfields around the world, and most particularly in China. The main countries affected by coal fires include China, India, the United States, Australia, Indonesia and South Africa. The fires cause sinkholes; large-scale subsidence; air pollution in the form of greenhouse gases; global warming; loss of mining productivity; contamination of drinking water; damage of flora and fauna; and a high safety risk. Therefore, protecting the economically valuable coal resources and the environment is of significant national and international importance. This paper discussed the use of paste backfill in the Wuda Inner Mongolia coalfield to cool down the burning coal and cut off the air supply to prevent coal fires. The study investigated backfill materials and techniques suited for underground coal fires. The paper presented the results of laboratory tests that were conducted on physical, chemical and mechanical properties of different backfill materials and mixtures, with particular attention to materials generated as by-products and other cheaply available materials such as fly ash from power plants. The characteristics of backfill materials, grain size analysis, and chemical composition of backfill were also identified. It was concluded that backfilling voids enhance the stability of the mine, thereby improving safety for the workforce. 4 refs., 2 tabs., 4 figs.

  11. Status of Research on Magnesium Oxide Backfill

    Energy Technology Data Exchange (ETDEWEB)

    PAPENGUTH,HANS W.; KRUMHANSL,JAMES L.; BYNUM,R. VANN; WANG,YIFENG; KELLY,JOHN W.; ANDERSON,HOWARD; NOWAK,E. JAMES

    2000-07-31

    For the WIPP, chemical and physical characteristics of MgO suggest it to be the most beneficial backfill choice, particularly because it has the ability to buffer the aqueous chemical conditions to control actinide volubility. In the current experimental program, the authors are developing a technical basis for taking credit for the complete set of attributes of MgO in geochemical, hydrogeological, and geomechanical technical areas, resulting in an improved conceptual model for the WIPP such as the following. Water uptake by MgO will delay the development of mobile actinides and gas generation by microbes and corrosion. Reduced gas generation will reduce or even eliminate spallings releases. As MgO hydrates, it swells, reducing porosity and permeability, which will inhibit gas flow in the repository, in turn reducing spallings releases. Hydration will also result in a self-sealing mechanism by which water uptake and swelling of MgO adjacent to a groundwater seep cuts off further seepage. Reaction with some groundwaters will produce cementitious materials, which will help to cement waste particles or produce a cohesive solid mass. Larger particles are less likely to be entrained in a spallings release. If sufficient water eventually accumulates in a repository to support microbial gas generation, magnesium carbonate cements will form; also producing good cohesion and strength.

  12. System design of backfill - An ongoing project with the aim to test SKB's backfill installation concept in tunnel conditions

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. SKB in Sweden is developing and implementing concepts for final disposal of spent nuclear fuel. A KBS-3V repository consists of deposition tunnels with copper canisters containing spent fuel placed in vertical deposition holes. The canisters are embedded in highly compacted bentonite. After placement of canisters and bentonite, the deposition tunnels are backfilled with pre-compacted blocks of bentonite stacked on a bed of bentonite pellets. The remaining slot between the blocks and rock wall will be filled with bentonite pellets. The project described in this abstract is an ongoing project aiming to further develop the concept for backfill described in SKB's licence application for a Spent Fuel Repository in Forsmark. Results from this project will give important input for the Preliminary Safety Analysis Report (PSAR) needed to get permission to start the construction of the Spent Fuel Repository. The main objective with this project is to ensure that the method selected for backfill including methods for inspection works as intended with reasonable efficiency. The backfill design needs to be set since it forms the basis for requirements on deposition tunnels, deposition sequence etc. This project System Design of Backfill was started in early 2010 and will continue until the end of 2013. The project budget is 26 MSEK. The work consists of investigations, calculations, laboratory tests, tests in the Bentonite Laboratory and underground tests at Aespoe HRL, Sweden. The project objective is to further develop SKB's reference concept for backfill by performing a system design and to ensure that the reference method works as intended with reasonable efficiency. The stacking pattern for backfill blocks has been developed, see Figure 1. A stacked brick pattern is more stable than a pattern with continuous joints which implies less need for a compacted foundation bed. A conclusion from performed tests is that it is

  13. Tests to determine water uptake behaviour of tunnel backfill

    International Nuclear Information System (INIS)

    A series of 27 large-scale tests have been completed at the 420 level of SKB's Aespoe Hard Rock Laboratory. These tests have examined the influence of natural Aespoe fracture zone water on the movement of water into and through assemblies of Friedland clay blocks and bentonite pellets/ granules. These tests have established the manner in which groundwater may influence backfill and backfilling operations at the repository-scale. Tests have established that it is critical to provide a clay block backfilling system with lateral support and confinement as quickly as possible following block installation. Exposure of the blocks to even low rates of water ingress can result in rapid loss of block cohesion and subsequent slumping of the block materials into the spaces between the blocks and the tunnel walls. Installation of granular or pelletized bentonite clay between the blocks and the walls resulted in a system that was generally stable and not prone to unacceptable short-term strains as water entered. Inflow of water into a backfilled volume does not result in uniform wetting of the pellet/granule filled volume and as a result there is the potential for rapid movement of water from the point(s) of ingress to the downstream face of the backfill. Depending on the inflow rate and flow path(s) developed this flow can be via discrete flow channels that are essentially non-erosive or else they can develop highly erosive flow paths through the clay block materials. Erosion generally tends to be highest in the period immediately following first water exit from the backfill and then decreases as preferential flow paths develop to channel the water directly through the backfill, bypassing large volumes of unsaturated backfill. At the scale examined in this study inflow rates of 0.1 l/min or less do not tend to be immediately problematic when the source is 0.6 m distant from the downstream face of the backfill. At larger scales or longer distances from the working face, it is

  14. Tests to determine water uptake behaviour of tunnel backfill

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, David (Atomic Energy of Canada Limited (AECL) (Canada)); Anttila, S.; Viitanen, M. (Poeyry InfRa Oy (Finland)); Keto, Paula (Saanio and Riekkola Oy, Helsinki (Finland))

    2008-12-15

    A series of 27 large-scale tests have been completed at the 420 level of SKB's Aespoe Hard Rock Laboratory. These tests have examined the influence of natural Aespoe fracture zone water on the movement of water into and through assemblies of Friedland clay blocks and bentonite pellets/ granules. These tests have established the manner in which groundwater may influence backfill and backfilling operations at the repository-scale. Tests have established that it is critical to provide a clay block backfilling system with lateral support and confinement as quickly as possible following block installation. Exposure of the blocks to even low rates of water ingress can result in rapid loss of block cohesion and subsequent slumping of the block materials into the spaces between the blocks and the tunnel walls. Installation of granular or pelletized bentonite clay between the blocks and the walls resulted in a system that was generally stable and not prone to unacceptable short-term strains as water entered. Inflow of water into a backfilled volume does not result in uniform wetting of the pellet/granule filled volume and as a result there is the potential for rapid movement of water from the point(s) of ingress to the downstream face of the backfill. Depending on the inflow rate and flow path(s) developed this flow can be via discrete flow channels that are essentially non-erosive or else they can develop highly erosive flow paths through the clay block materials. Erosion generally tends to be highest in the period immediately following first water exit from the backfill and then decreases as preferential flow paths develop to channel the water directly through the backfill, bypassing large volumes of unsaturated backfill. At the scale examined in this study inflow rates of 0.1 l/min or less do not tend to be immediately problematic when the source is 0.6 m distant from the downstream face of the backfill. At larger scales or longer distances from the working face, it

  15. Piping and erosion in buffer and backfill materials. Current knowledge

    International Nuclear Information System (INIS)

    The water inflow into the deposition holes and tunnels in a repository will mainly take place through fractures in the rock and will lead to that the buffer and backfill will be wetted and homogenised. But in general the buffer and backfill cannot absorb all water that runs through a fracture, which leads to that a water pressure will be generated in the fracture when the inflow is hindered. If the counter pressure and strength of the buffer or backfill is insufficiently high, piping and subsequent erosion may take place. The processes and consequences of piping and erosion have been studied in some projects and several laboratory test series in different scales have been carried through. This brief report describes these tests and the results and conclusions that have emerged. The knowledge of piping and erosion is insufficient today and additional studies are needed and running

  16. Ocean disposal of heat generating radioactive waste backfilling requirements

    International Nuclear Information System (INIS)

    This report describes the backfilling requirements arising from the disposal of HGW in deep ocean sediments. The two disposal options considered are the drilled emplacement method and the free fall penetrator method. The materials best suited for filling the voids in the two options are reviewed. Candidate materials are selected following a study of the property requirements of each backfill. Placement methods for the candidate materials, as well as the means available for verifying the quality of the filling, are presented. Finally, an assessment of the overall feasibility of each placement method is given. The main conclusion is that, although the proposed methods are feasible, further work is necessary to test in inactive trials each of the proposed filling methods. Moreover, it is difficult to envisage how two of the backfilling operations in drilled emplacement option can be verified by non destructive methods. (author)

  17. Backfilling of deposition tunnels: Use of bentonite pellets

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, David (Atomic Energy of Canada Limited (Canada)); Sanden, Torbjoern (Clay Technology AB (Sweden)); Jonsson, Esther (Swedish Nuclear Fuel and Waste Mangaement Co. (Sweden)); Hansen, Johanna (Posiva Oy (Finland))

    2011-02-15

    The state of knowledge related to use of bentonite pellets as part of backfill or other gap filling components in repository applications is reviewed. How the pellets interact with adjacent sealing materials and the surrounding rock mass is a critical aspect in determining backfill behaviour. The key features and processes that determine how the pellet component of the KBS-3V deposition tunnel backfill will behave are discussed and recommendations related to what additional information needs to be developed are provided. Experiences related to pellet material composition, size, shape, placement options and more importantly, the density to which they can be placed all indicate that there are significant limitations to the achievable as-placed density of bentonite pellet fill. Low as-placed density of the pellet fill component of the backfill is potentially problematic as the outermost regions of tunnel backfill will be the first region of the backfill to be contacted by water entering the tunnels. It is also through this region that initial water movement along the length of the deposition tunnels will occur. This will greatly influence the operations in a tunnel, especially with respect to situations where water is exiting the downstream face of still open deposition tunnels. Pellet-filled regions are also sensitive to groundwater salinity, susceptible to development of piping features and subsequent mechanical erosion by through flowing water, particularly in the period preceding deposition tunnel closure. A review of the experiences of various organisations considering use of bentonite-pellet materials as part of buffer or backfill barriers is provided in this document. From this information, potential options and limitations to use of pellets or pellet-granule mixtures in backfill are identified. Of particular importance is identification of the apparent upper-limits of dry density to which such materials can to be placed in the field. These bounds will

  18. On the risk of liquefaction of buffer and backfill

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, R. [Geodevelopment AB, Lund (Sweden)

    2000-10-01

    The necessary prerequisites for liquefaction of buffers and backfills in a KBS-3 repository exist but the stress conditions and intended densities practically eliminate the risk of liquefaction for single earthquakes with magnitudes up to M=8 and normal duration. For buffers rich in expandable minerals it would be possible to reduce the density at water saturation to 1,700 - 1,800 kg/m{sup 3} or even less without any significant risk of liquefaction, while the density at saturation of backfills with 10 - 15% expandable clay should not be reduced to less than about 1,900 kg/m{sup 3}. Since the proposed densities of both buffers and backfills will significantly exceed these minimum values it is concluded that there is no risk of liquefaction of the engineered soil barriers in a KBS-3 repository even for very significant earthquakes.

  19. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Science.gov (United States)

    2010-07-01

    ... environment. (5) Spoil placed on the outslope during previous mining operations shall not be disturbed if such... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Backfilling and grading. 819.19 Section 819.19 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF...

  20. Ion-exchange equilibria and diffusion in engineered backfill

    International Nuclear Information System (INIS)

    Engineered backfill can add confidence to confinement times of high-level nuclear waste stored in geologic media. This paper discusses the design and operation of a unique radial-flow diffusion cell to determine ion migration rates in backfill material under realistic repository conditions. New experimental results were reported for diffusion of CsCl in a background of NaCl into compacted bentonite and bentonite/quartz mixtures. Representation of the measured diffusion rates by the traditional, homogeneous porous-medium model significantly underestimates cesium penetration distances into the backfill. Surface diffusion is suggested as an additional mechanism by which cations transport in swollen montmorillonite; the surface diffusion coefficients for cesium is determined to be approximately 10-7 cm2/s. An electrostatic site-binding model is developed for ion-exchange equilibria on montmorillonite clay. The effect of pH, ionic strength, and specific adsorption are evaluated and compared favorably to new, experimental exchange isotherms measured on disaggregated clay. The electrostatic site-binding model permits a prediction of the influence of backfill compaction on K/sub d/ values. We find that for strongly adsorbing cations, compactions has little effect. However, anions exhibit significant Donnan exclusion with clay compaction. 40 references, 12 figures

  1. The Buffer and Backfill Handbook. Part 2: Materials and techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Roland [Geodevelopment AB, Lund (Sweden)

    2001-12-01

    Improved technology and prospection yielding more pure and homogeneous raw materials for preparing buffers and backfills will ultimately outdate the clays and ballast materials described in the present part of the Handbook. It describes experimentally investigated materials of potential use in repositories but other, more suitable materials will replace them in the future. The Handbook will hence have to be reviewed regularly, making room for superior materials in future, upgraded Handbook versions. Buffer is the term for dense clay used for embedment of canisters with highly radioactive waste, while backfill is soil used for filling tunnels and shafts in repositories. Examples of soil materials of potential use as buffers and backfills in repositories of KBS-3 type are described in this part of the Handbook. They are: smectitic clay materials intended for preparation of buffers (canister-embedding clay) and used as clay component in artificially prepared tunnel and shaft backfills consisting of mixtures of clay and ballast. Ballast materials intended for backfilling of tunnels and shafts and used as components of artificially prepared backfills. Smectitic natural clay soils intended for use as buffers and backfills. Very fine-grained smectite clay used as grout for sealing rock fractures. In this part of the Handbook for Buffers and Backfills, description of various candidate materials will be made with respect to their mineral composition and physical properties, with respect to the groundwater chemistry that can be expected in a deep repository in Swedish bedrock. Chapter 3 deals with smectitic clay materials intended for embedment of heat-producing canisters with highly radioactive waste. Focus is on the nature of the buffer constituents, i. e. the smectite content, the non-expanding clay minerals colloidal and the accessory non-clay minerals as well as amorphous matter and organic substances. The dominant part of the chapter describes the occurrence and origin

  2. The Buffer and Backfill Handbook. Part 2: Materials and techniques

    International Nuclear Information System (INIS)

    Improved technology and prospection yielding more pure and homogeneous raw materials for preparing buffers and backfills will ultimately outdate the clays and ballast materials described in the present part of the Handbook. It describes experimentally investigated materials of potential use in repositories but other, more suitable materials will replace them in the future. The Handbook will hence have to be reviewed regularly, making room for superior materials in future, upgraded Handbook versions. Buffer is the term for dense clay used for embedment of canisters with highly radioactive waste, while backfill is soil used for filling tunnels and shafts in repositories. Examples of soil materials of potential use as buffers and backfills in repositories of KBS-3 type are described in this part of the Handbook. They are: smectitic clay materials intended for preparation of buffers (canister-embedding clay) and used as clay component in artificially prepared tunnel and shaft backfills consisting of mixtures of clay and ballast. Ballast materials intended for backfilling of tunnels and shafts and used as components of artificially prepared backfills. Smectitic natural clay soils intended for use as buffers and backfills. Very fine-grained smectite clay used as grout for sealing rock fractures. In this part of the Handbook for Buffers and Backfills, description of various candidate materials will be made with respect to their mineral composition and physical properties, with respect to the groundwater chemistry that can be expected in a deep repository in Swedish bedrock. Chapter 3 deals with smectitic clay materials intended for embedment of heat-producing canisters with highly radioactive waste. Focus is on the nature of the buffer constituents, i. e. the smectite content, the non-expanding clay minerals colloidal and the accessory non-clay minerals as well as amorphous matter and organic substances. The dominant part of the chapter describes the occurrence and origin

  3. A New Mode of Coal Mining Under Buildings with Paste-Like Backfill Technology

    Institute of Scientific and Technical Information of China (English)

    崔建强; 孙恒虎; 黄玉诚

    2002-01-01

    The formation of the paste-like backfill technology was introduced briefly in this paper. From the actual cases of coal mines, a new mode of coal mining un der buildings with the technology was proposed. And its specificity was analyzed , and a further introduction to the full-sand-soil solidifying material was given. The main parts of the backfill system, such as the backfill preparation system, the pipeline transportation system, the backfill systems in fully-mechanized mining faces and the backfill process, were presented emphatically.

  4. Radon emanation from backfilled mill tailings in underground uranium mine

    International Nuclear Information System (INIS)

    Coarser mill tailings used as backfill to stabilize the stoped out areas in underground uranium mines is a potential source of radon contamination. This paper presents the quantitative assessment of radon emanation from the backfilled tailings in Jaduguda mine, India using a cylindrical accumulator. Some of the important parameters such as 226Ra activity concentration, bulk density, bulk porosity, moisture content and radon emanation factor of the tailings affecting radon emanation were determined in the laboratory. The study revealed that the radon emanation rate of the tailings varied in the range of 0.12–7.03 Bq m−2 s−1 with geometric mean of 1.01 Bq m−2 s−1 and geometric standard deviation of 3.39. An increase in radon emanation rate was noticed up to a moisture saturation of 0.09 in the tailings, after which the emanation rate gradually started declining with saturation due to low diffusion coefficient of radon in the saturated tailings. Radon emanation factor of the tailings varied in the range of 0.08–0.23 with the mean value of 0.21. The emanation factor of the tailings with moisture saturation level over 0.09 was found to be about three times higher than that of the absolutely dry tailings. The empirical relationship obtained between 222Rn emanation rate and 226Ra activity concentration of the tailings indicated a significant positive linear correlation (r = 0.95, p < 0.001). This relationship may be useful for quick prediction of radon emanation rate from the backfill material of similar nature. - Highlights: • 222Rn emanation rate of the backfilled tailings varied from 0.12 to 7.03 Bq m−2 s−1. • Good correlation between 222Rn emanation rate and 226Ra activity concentration found. • Higher 222Rn emanation rate was obtained from moist backfilled tailings. • Radon emanation factor of the backfilled tailings varied in the range of 0.08–0.23. • Emanation factor of wet tailings was about 3 times higher than that of dry tailings

  5. Geotechnical investigations on backfill materials in the Asse salt mine

    International Nuclear Information System (INIS)

    The compression behaviour of rock salt grit is being investigated by compression tests at the Asse salt mine. The various test parameters are introduced and their results are discussed. The permeability of rock salt grit with saturated NaCl-brine in dependency upon the grain size and compactness, resp. the porosity, is being determined at the Asse salt mine. The test equipment and the results determined here are shown. In addition to laboratory tests, geotechnical investigations are taking place in a carnallitic chamber of the Asse salt mine which had been backfilled in earlier years. They chiefly concern measurements of the deformation rates in drifts - which were mined between the chambers in remaining pillars - as well as horizontal deformation measurements in the backfilling. (orig./DG)

  6. Reactive backfills in radioactive waste disposal selenium sorption on apatite

    International Nuclear Information System (INIS)

    Apatites are investigated as possible high performance material for reactive backfills in radioactive waste disposal. An experimental study showed an excellent selenite retaining rate and established the main characteristic of this element sorption on natural and synthetic apatites. Thermodynamical parameters have been calculated and integrated in a geochemical computer code in order to demonstrate the excellent potentialities of the apatite as a trap mineral for the selenium. (A.L.B.)

  7. Approach for Measuring Swelling Stress of Buffer Backfilling Material

    OpenAIRE

    Ming Zhang; Huyuan Zhang; Suli Cui; Lingyan Jia

    2012-01-01

    The characteristics of swelling stress of buffer backfilling material have been studied by forcebalance method and constant volume test method in this paper. The constant volume test apparatus was designed by the authors. Results show that swelling stress changing with time is a little different between the two methods. The value of swelling stress measured by constant volume test is more accurate; besides, uptaking water with time could also be monitored by constant volume test. The constant...

  8. Effect of Initial Backfill Temperature on the Deformation Behavior of Early Age Cemented Paste Backfill That Contains Sodium Silicate

    Directory of Open Access Journals (Sweden)

    Aixiang Wu

    2016-01-01

    Full Text Available Enhancing the knowledge on the deformation behavior of cemented paste backfill (CPB in terms of stress-strain relations and modulus of elasticity is significant for economic and safety reasons. In this paper, the effect of the initial backfill temperature on the CPB’s stress-strain behavior and modulus of elasticity is investigated. Results show that the stress-strain relationship and the modulus of elasticity behavior of CPB are significantly affected by the curing time and initial temperature of CPB. Additionally, the relationship between the modulus of elasticity and unconfined compressive strength (UCS and the degree of hydration was evaluated and discussed. The increase of UCS and hydration degree leads to an increase in the modulus of elasticity, which is not significantly affected by the initial temperature.

  9. Backfilling of KBS-3V deposition tunnels - possibilities and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Wimelius, Hans (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Pusch, Roland (Geodevelopment International AB, Lund (Sweden))

    2008-12-15

    By definition for the SKB repository concept, the backfill of KBS-3V deposition tunnels must be so designed that transport of dissolved matter is controlled by diffusion and not by advective water flow. This requires that the hydraulic conductivity of the backfill does not exceed about E-10 m/s. The backfilling materials also have to adequately resist compression caused by upward expansion of the buffer. It must also exert an effective pressure of at least 100 kPa on the rock in order to provide support to the rock and minimize spalling of the rock. These criteria are fulfilled by several approaches and options for backfill materials, placed and compacted layer wise or in the form of blocks of compacted clay powder. Based on the experience from comprehensive lab studies and considering practical issues, SKB has selected a concept where the major part of the backfill consists of stacked blocks that are surrounded by clay pellets. Using this concept a basis for a detailed evaluation, a study of three different techniques for placing the blocks has been undertaken. The three block placement techniques examined are the 'Block', 'Robot', and 'Module' methods. They involve different block sizes and techniques for handling and placing the blocks but the same way of preparing the foundation bed of the blocks and placing the pellet filling. The blasted tunnels have a varying cross section, caused by the orientation of the blast-holes. This requires that a varying fraction of blocks be installed in the backfilling along the blasted tunnel interval if sufficiently high density and low hydraulic conductivity is to be achieved. The efficiency of filling will depend on the type of clay used in the blocks. For example, using Friedland clay for block preparation, the filling efficiency must be 80% while it can be reduced to 60% if more smectite-rich clay is used. The use of a clay with high smectite content increases margins and is concluded to be

  10. Backfilling technology and strata behaviors in fully mechanized coal mining working face

    Institute of Scientific and Technical Information of China (English)

    Zhang Qiang; Zhang Jixiong; Huang Yanli; Ju Feng

    2012-01-01

    Based on the principle of fully mechanized backfilling and coal mining technology and combined with theXingtai Coal Mine conditions,we mainly optimized the coal mining equipment and adjusted the coal mining method in the Xingtai Coal Mine 7606 working face for implementation this technology,Firstly,we define the practical backfilling process as the "(from backfilling scraper conveyor's) head to tail backfilling,step by step swinging up of the tamping arm.gradual compacting,moving formed backfilling scraper conveyor when the second tamping arm cannot pass and connecting the immediate roof by back material push front material movement".Meanwhile,the stress changes of backfill body in coal mined out area was monitored by stress sensors,and the roof caving law was analyzed by monitoring the dynamic subsidence of -210 west roadway of this face.The site tests results show that using this new backfilling and coal mining integrated technology,the production capacity in the 7606 working face can reach to 283,000 ton a year,and 282,000 ton of solid materials (waste and fly ash) is backfilled,which meets the needs of high production and efficiency.The goaf was compactly backfilled with solid material and the strata behavior was quite desirable,with an actual maximum vertical stress of the backfill body of 5.5 MPa.Backfill body control the movement of overburden within a certain range,and there is no collapses of major areas in the overlying strata upon backfilled gob.The maximum subsidence and speed were 231 mm and 15.75 mm/d respectively,which proved the practical significance of this integrated technology.

  11. Investigations on backfilling and sealing of chambers and shafts in a final salt repository

    International Nuclear Information System (INIS)

    Soil mechanical laboratory investigations as well as geotechnical in situ measurements were carried out. The laboratory tests provided important information on the material behaviour of selected backfill and sealing materials. Initial conclusions on the long-term behaviour of backfill and seals as well as on their interaction with the rock were gained with the results of in situ measurements in backfilled chambers and seals and in the surrounding rock of the Asse salt mine. (orig./DG)

  12. Geotechnical charcterization of coal refuse for use as a backfill material

    OpenAIRE

    Bowman, Charles H

    1991-01-01

    Both active and residual mine subsidence resulting from underground coal mining have caused surface damage to land and structures. A method of subsidence mitigation successfully used abroad, and to a much lesser extent in U.S. coal mines, is backfilling. In addition to the possible benefits of subsidence mitigation, backfilling has the potential to increase coal recovery, enhance ventilation control, and to minimize mine fires. Backfilling can also be used as a means of mine refuse disposal, ...

  13. Relative Density of Backfilled Soil Material around Monopiles for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Frigaard, Peter

    2012-01-01

    The relative density of backfilled soil material around offshore monopiles is assessed through experimental testing in the Large Wave Channel (GWK) of the Coastal Research Centre (FZK) in Hannover. The relative density of the backfill material was found to vary between 65 and 80 %. The dependency...... of the relative density of backfill on the maximum pile bending moment is assessed through three-dimensional numerical modeling of a monopile foundation located at the offshore wind farm at Horns Reef, Denmark....

  14. Effects of grouting, shotcreting and concrete leachates on backfill geochemistry

    International Nuclear Information System (INIS)

    The use of concrete to seal open fractures (grouting) and to impermeabilise the deposition tunnels (shotcreting) has been envisaged in the construction of a high level nuclear waste (HLNW) repository according to SKB designs. Nevertheless, the geochemical effect of using concrete in the repository is not fully understood. Concrete degradation due to the interaction with groundwater can affect the performance of other repository barriers, such as the backfill material used for sealing the deposition tunnels. One of the main effects of concrete degradation is the generation of alkaline plumes. For this reason, SKB is currently planning to use a type of concrete whose degradation result in lower pH values than those developed with Ordinary Portland Cement (OPC). In order to assess the long-term geochemical effect of including low-pH concrete elements in a HLNW repository, we performed a 2D reactive-transport model of a backfilled deposition tunnel that intersects a hydraulic conductive fracture which has been partially grouted. An additional case has been modelled where part of the deposition tunnel walls were covered with a shotcrete layer. The modelling results predict the development of a high-alkalinity plume, larger in the case of considering a grouted fracture, accompanied by the precipitation of CSH-phases in the fracture. However, the effect on the backfill material is only significant if concrete is in contact with the backfill (shotcrete case). In order to conduct these models, and considering that at the beginning of the present work there was not a specific composition for such a low-pH concrete, its composition has been assumed in order to meet the expected geochemical evolution of concrete degradation according to SKB expectations. This is a pH of pore water of around 11 and the degradation of CSH phases resulting in a source for Ca and Si into the system. For this reason, jennite and tobermorite have been selected, although it is known that jennite is

  15. Effects of grouting, shotcreting and concrete leachates on backfill geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Luna, Miguel; Arcos, David; Duro, Lara [Enviros Consulting, Valldoreix, Barc elona (Spain)

    2007-11-15

    The use of concrete to seal open fractures (grouting) and to impermeabilise the deposition tunnels (shotcreting) has been envisaged in the construction of a high level nuclear waste (HLNW) repository according to SKB designs. Nevertheless, the geochemical effect of using concrete in the repository is not fully understood. Concrete degradation due to the interaction with groundwater can affect the performance of other repository barriers, such as the backfill material used for sealing the deposition tunnels. One of the main effects of concrete degradation is the generation of alkaline plumes. For this reason, SKB is currently planning to use a type of concrete whose degradation result in lower pH values than those developed with Ordinary Portland Cement (OPC). In order to assess the long-term geochemical effect of including low-pH concrete elements in a HLNW repository, we performed a 2D reactive-transport model of a backfilled deposition tunnel that intersects a hydraulic conductive fracture which has been partially grouted. An additional case has been modelled where part of the deposition tunnel walls were covered with a shotcrete layer. The modelling results predict the development of a high-alkalinity plume, larger in the case of considering a grouted fracture, accompanied by the precipitation of CSH-phases in the fracture. However, the effect on the backfill material is only significant if concrete is in contact with the backfill (shotcrete case). In order to conduct these models, and considering that at the beginning of the present work there was not a specific composition for such a low-pH concrete, its composition has been assumed in order to meet the expected geochemical evolution of concrete degradation according to SKB expectations. This is a pH of pore water of around 11 and the degradation of CSH phases resulting in a source for Ca and Si into the system. For this reason, jennite and tobermorite have been selected, although it is known that jennite is

  16. Behavior of Radionuclides and RCRA Elements in Tank Backfill Grouts

    International Nuclear Information System (INIS)

    One approach to decommissioning emptied high-level waste tanks is to backfill them with grout. Because of the long lives and high toxicity of some of the contaminants, the chemical behavior of the contaminants in the grout need to be understood, especially as the grout ages and weathers over long times. In this paper, the sequestration of technetium and iodine in contact with two grout formulations, and their component materials, is discussed. Preliminary results are presented of experiments examining the solubility of actinides in contact with the grouts as pH is lowered and carbonate content increased, representing conditions of a weathered grout system. (authors)

  17. Retention Capability of Local Backfill Materials 1-Simulated Disposal Environment

    International Nuclear Information System (INIS)

    In Egypt, a shallow ground disposal facility was the chosen option for the disposal of low and and intermediate radioactive wastes. The impact of the waste disposal facility on the environment depends on the nature of the barriers, which intend to limit and control contaminant migration. Owing to their physical, chemical and mechanical characteristics. Local soil materials were studied to illustrate the role of the back fill as part of an optimized safety multi-barrier system, which can provide the required level of protection of the environment and meet economic and regulatory requirements. A theoretical model was proposed to calculate the transport phenomena through the backfill materials. The credibility and validity of the proposed model was checked by the experimental results obtained from a three-arms arrangement system. The obtained data for the distribution coefficient (Kd) and the apparent diffusion coefficient (Da) were in good agreement with those previously obtained in the literatures. Taking in consideration the prevailing initial conditions, the data calculated by the theoretical model applied show a reasonable agreement with the results obtained from experimental work. Prediction of radioactive cesium migration through the backfill materials using the proposed model was performed as a function of distance. The results obtained show that after 100 years, a fraction not exceeding 1E-9 of the original activity could be detected at 1m distance away from the waste material

  18. Flowable Backfill Materials from Bottom Ash for Underground Pipeline

    Directory of Open Access Journals (Sweden)

    Kyung-Joong Lee

    2014-04-01

    Full Text Available The purpose of this study was to investigate the relationship between strength and strain in manufacturing controlled low strength materials to recycle incineration bottom ash. Laboratory tests for controlled low strength materials with bottom ash and recycled in-situ soil have been carried out. The optimum mixing ratios were 25%–45% of in-situ soil, 30% of bottom ash, 10%–20% of fly ash, 0%–3% of crumb rubber, 3% of cement, and 22% of water. Each mixture satisfied the standard specifications: a minimum 20 cm of flowability and 127 kPa of unconfined compressive strength. The average secant modulus (E50 was (0.07–0.08 qu. The ranges of the internal friction angle and cohesion for mixtures were 36.5°–46.6° and 49.1–180 kPa, respectively. The pH of all of the mixtures was over 12, which is strongly alkaline. Small-scale chamber tests for controlled low strength materials with bottom ash and recycled in-situ soil have been carried out. Vertical deflection of 0.88–2.41 mm and horizontal deflection of 0.83–3.72 mm were measured during backfilling. The vertical and horizontal deflections of controlled low strength materials were smaller than that of sand backfill.

  19. 30 CFR 816.106 - Backfilling and grading: Previously mined areas.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Backfilling and grading: Previously mined areas...-SURFACE MINING ACTIVITIES § 816.106 Backfilling and grading: Previously mined areas. (a) Remining... opertions where the volume of all reasonably available spoil is demonstrated in writing to the...

  20. 30 CFR 817.106 - Backfilling and grading: Previously mined areas.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Backfilling and grading: Previously mined areas...-UNDERGROUND MINING ACTIVITIES § 817.106 Backfilling and grading: Previously mined areas. (a) Remining... operations where the volume of all reasonably available spoil is demonstrated in writing to the...

  1. Mechanical analysis of roof stability under nonlinear compaction of solid backfill body

    Institute of Scientific and Technical Information of China (English)

    Li Meng⇑; Zhang Jixiong; Liu Zhan; Zhao Xu; Huang Peng

    2016-01-01

    Based on the compaction characteristic test and the nonlinear compaction deformation characteristics of backfill material, this paper applies the theory of nonlinear elastic foundation of thin plate to establish a mechanical model of backfill body and roof in solid dense backfill coal mining. This study critically anal-yses the deflection equation of the roof by the energy method, derives the conditions of roof breakage and combined with concrete engineering practice analyses, determines roof movement regularity and stabil-ity in solid dense backfill mining. Analysis of the engineering practice of the 13,120 backfill panel of Pingmei 12# mine shows the theoretical maximum of roof convergence in backfill mining to be 415 mm which is in significant agreement with the measured value. During the advancing process of solid backfill mining at the panel, the maximum tensile stress on the roof is less than its tensile strength which does not satisfy the conditions for roof breakage. Drilling results on the roof and ground pressure monitoring show that the integrity of roof is strong, which is consistent with the theoretical calculations described in this study. The results presented in the study provide a basis for further investigation into strata movement theory in solid dense backfill mining.

  2. The backfilling and sealing of radioactive waste repositories. V. 2. Figure - Tables - Appendices

    International Nuclear Information System (INIS)

    The two volumes of this report present a review study about backfilling and sealing of radioactive waste repositories in granites, argillaceous and salt formations. Volume 2 contains all the figures, table and appendices A detailed account of candidate backfill materials is given in a standardized format

  3. Radionuclide sorption and migration studies of getters for backfill barriers

    International Nuclear Information System (INIS)

    Bentonite and hectorite clay minerals were chosen for study and development as potential backfill materials for testing in the proposed Waste Isolation Pilot Plant (WIPP), a radioactive waste repository and test facility in bedded salt. This choice of materials was based on initial screening results which are presented and on the predicted physical properties of these materials. These properties were verified experimentally in concentrated brines specific to the WIPP site. Distribution coefficients, K/sub d/, were calculated from batch sorption measurements on bentonite and hectorite in the nearly saturated brines A and B. The resulting K/sub d/ values were in the range of (1 to 5) x 103 ml/g for europium; (2 to 40) x 103 ml/g for plutonium(IV); and (4 to 16) x 103 ml/g for americium(III). A silica- and calcite-containing sand mixed with bentonite and hectorite acted as a sorber of americium(III) but was merely an inert diluent for plutonium(IV). Pertechnetate anions (TcO4-) sorbed on activated charcoal with K/sub d/ values in the range of (0.2 to 0.4) x 103 ml/g. Pertechnetate, cesium, and strontium ions in brine were not sorbed appreciably by bentonite or hectorite. Although experimental evidence is given for a possible role of solubility in the sorption of europium on getters, other data presented here and evidence from the literature are inconsistent with a simple single reaction sorption mechanism. It is concluded that a backfill containing bentonite on hectorite and activated charcoal is potentially an effective barrier to the migration of Eu(III), Pu(IV), and Am(III) cations and, with further development, to the migration of TcO4- anions as well

  4. Research on U-steel yieldable support with backfill technology in rock roadway

    Institute of Scientific and Technical Information of China (English)

    LUO Yong; CHANG Ju-cai

    2009-01-01

    The loading on U-steel yieldable support cannot be organically combined with the law of strata behaviors from the surrounding rocks of roadway. In order to effectively solve the problem, U-steel yieldable support with backfill material and the performance requirements of backfill material were analyzed on the basis of structural mechanics. The mechanical properties of backfill material selected were tested in the laboratory, and the test results show that the ratio of the backfill material complies with the requirements of backfill technology; it can effectively optimize the relationship between the support and the surrounding rock, and the filling layer can avoid the partial stress concentration and fully improve the support performance. Compared with U-steel yieldable support with gangue filling, the filed application shows that the supporting result of U-steel yieldable support with backfill technology is satisfactory, the stress on U-steel yieldable support with backfill technology decreases greatly and distributes uniformly, convergence of the surrounding rock of roadway is decreased by more than 50%, and the surrounding rocks of roadway are controlled effectively.

  5. Design and application of solid, dense backfill advanced mining technology with two pre-driving entries

    Institute of Scientific and Technical Information of China (English)

    Zhang Qiang; Zhang Jixiong; Guo Shuai; Gao Rui; Li Weikang

    2015-01-01

    New solid backfill mining technology provides unique technical advantages for‘three-under’ coal min-ing which refers to coal resources trapped under buildings, railways, and water bodies. This technology has a much higher recovery rate and can effectively control the surface subsidence. However, successful application of this technology depends heavily on geological conditions. To avoid the disadvantages asso-ciated with downward mining and overhead backfilling with this new technology, a new advanced solid backfill mining design with two pre-driving entries is proposed here to ensure the backfill effect. Taking Huayuan coal mine as an example, this paper tests the double gob-side entries retaining with no pillar left scheme and optimizes an integrated technology setup for backfill mining and gob-side entry retain-ing. Field applications show that the recovery rate increased from 40%for strip mining to 85%for backfill mining. Moreover, the new backfill technology allowed for better control over the surrounding rock deformation caused by the gob-side entry retaining effect and better control of ground subsidence as compared to strip mining.

  6. Physical response of backfill materials to mineralogical changes in a basalt environment

    International Nuclear Information System (INIS)

    Backfill materials surrounding waste canisters in a high-level nuclear waste repository are capable of ensuring very slow flow of groundwater past the canisters, and thereby increase the safety of the repository. However, in the design of a repository it will be necessary to allow for possible changes in the backfill. In this experimental program, changes in permeability, swelling behavior, and plastic behavior of the backfill at the temperatures, pressures, and radiation levels expected in a repository are investigated. The emphasis is on investigation of relevant phenomena and evaluation of experimental procedures for use in licensing procedures. The permeability of a slightly compacted sand-clay mixture containing 25% bentonite, with a dry bulk density of 1.59 g/cm3, was determined to be 0.9 x 10-18 m2 in liquid water at 25 and 2000C, respectively. This is sufficiently low to demonstrate the potential effectiveness of proposed materials. In practice, fractures in the host rock may form short circuits around the backfill, so an even lower flow rate is probable. However, alteration by any of several mechanisms is expected to change the properties of the backfill. Crushed basalt plus bentonite is a leading candidate backfill for a basalt repository. Experiments show that basalt reacts with groundwater vapor or with liquid groundwater producing smectites, zeolites, silica, and other products that may be either beneficial or detrimental to the long-term performance of the backfill. Concentration of groundwater salts in the backfill by evaporation would cause immediate, but possibly reversible, reduction of the swelling abaility of bentonite. Moreover, under some circumstances, gamma radiolysis of moist air in the backfill could produce up to 0.5 mole of nitric acid or ammonia per liter of pore space. 27 references, 7 figures, 4 tables

  7. Evaluation of using synthetic zeolite as a backfill material in radioactive waste disposal facility

    International Nuclear Information System (INIS)

    The fundamental safety concept for the disposal of radioactive wastes is to isolate the waste from the accessible environment for a period sufficiently long to allow substantial decay of the radionuclides and to limit release of residual radionuclides into the accessible environment. The underground disposal of radioactive waste is based upon a multi barrier concept. Backfill material is an important component of a multi-barrier disposal facility for low and intermediate level radioactive wastes. For long-term performance assessment of radioactive repositories, knowledge concerning the migration of radionuclides in the backfill material is required. Radionuclide migration through porous media (backfill materials) is governed by diffusion, advection, dispersion, retardation, and radionuclide decay. The work presented in this thesis is an examination of the feasibility of using synthetic zeolite NaA-X blend prepared from fly ash (FA) as backfill material in the proposed radioactive waste disposal facility in Egypt. The migration behavior of cesium and strontium ions, as two of the most important radionuclides commonly encountered in the Egyptian waste streams, through the proposed backfill material is studied using mathematical models. This approach considers the advective and dispersive transport of solutes dissolved in groundwater, which may undergo linear sorption (i.e retardation) and simple first order decay. To achieve these goals, the following investigations were carried out:1- Review of the materials most commonly used as engineered backfill to identify the important features to be considered in the examination of the proposed backfill material (zeolite Na A-X blend).2- Sorption experimental investigation aimed to study the sorption properties of the candidate backfill material towards the concerned radionuclides, cesium and strontium. Such studies are performed to establish clear understanding of the principle factors that control the sorption process, i

  8. Realizing of Optimization of Binder Backfill Material Under Certain Strength with Fuzzy Sets

    Institute of Scientific and Technical Information of China (English)

    崔明义; 胡华

    2001-01-01

    The main factors deciding the compressive strength of binder backfill body are tailing density and binder dosage in binder backfill materials. Based on the antecedent of certain pulp density, the method of increasing the tailing density and reducing the binder dosage, or the manner of cutting down the tailing density and gaining the binder dosage are taken to guarantee the strength of backfill body. The problem that should be solved is how to determine the tailing density and the binder dosage rationally. This paper tries to realize the correct selection of the tailing density and the binder dosage in computer with the method of fuzzy mathematics.

  9. Engineering solution for the backfilling and sealing of radioactive waste repositories

    International Nuclear Information System (INIS)

    To ensure the safety of radioactive waste deep disposal, backfilling and sealing materials (engineered barriers) have to be used to fill residual voids. For granite medium, stress is put on emplacement techniques for cement- and clay-based materials, including in-situ validation. For clay medium, mined repository and deep boreholes drilled from the surface are considered. In the case of the first solution, the thermomechanical behaviour of a clay backfill is studied. In the same way, backfill made of excavated crushed salt is considered and thermomechanical properties evaluated by means of laboratory tests and in-situ experiments. Finally, basic works on quality assurance procedures and historic concretes behaviour are reported

  10. The backfilling and sealing of radioactive waste repositories. V. 1. Text - Reference - List of symbols

    International Nuclear Information System (INIS)

    The report is in two volumes: Volume 1 contains the main text, the references and a list of symbols, and Volume 2, all the figues, tables and appendices. In Volume 1, backfilling and sealing is considered in relation to the geological, physical and chemical environments. There follows a detailed evaluation of the role and performance of the backfilling and sealing system in terms of thermal, hydraulic, chemical buffering, radionuclide retention, mechanical properties and behaviour as well as longevity. The results of the listing, screening and classification of a comprehensive range of candidate backfill materials are summarized. The different candidate materials are examined

  11. Use of cemented paste backfill in arsenic-rich tailings

    Science.gov (United States)

    Hamberg, Roger; Maurice, Christian; Alakangas, Lena

    2015-04-01

    Gold is extracted by cyanide leaching from inclusions in arsenopyrite from a mine in the north of Sweden. The major ore mineral assemblage consists of pyrrhotite and arsenopyrite-loellingite. Effluents from the gold extraction were treated with Fe2(SO4)3, with the aim to form stable As-bearing Fe-precipitates (FEP). The use of the method called cemented paste backfill (CPB) is sometimes suggested for the management of tailings. In CPB, tailings are commonly mixed with low proportions (3 - 7 %) of cement and backfilled into underground excavated area. To reduce costs, amendments such as granulated blast furnace slag (GBFS), biofuel fly ash (BFA) and cement kiln dust (CKD) are used for partial replacement of cement in CPB due to their pozzolanic and alkaline properties. The objective for this study was to evaluate the leaching behaviour of As in CPB-mixtures with low proportions (1 - 3 %) of BFA and ordinary cement and unmodified tailings. The selection of CPB-recipies was made based on technical and economical criterias to adress the demands deriving from the mining operations. Speciation of the As in ore and tailings samples revealed that mining processes have dissolved the majority of the arsenopyrite in the ore, causing secondary As phases to co-precipitate with newly formed FEP:s. Tank leaching tests (TLT) and weathering cells (WCT) were used to compare leaching behaviour in a monolithic mass contra a crushed material. Quantification of the presumed benefit of CPB was made by calculation of the cumulative leaching of As. Results from the leaching tests (TLT and WCT) showed that the inclusion of As-rich tailings into a cementitious matrix increased leaching of As. This behaviour could partially be explained by an increase of pH. The addition of alkaline binder materials to tailings increased As leaching due to the relocation of desorbed As from FEPs into less acid-tolerant species such as Ca-arsenates and cementitious As-phases. Unmodified tailings generated an

  12. Deep repository - engineered barrier systems. Assessment of backfill materials and methods for deposition tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Gunnarsson, David; Moren, Lena; Sellin, Patrik [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Keto, Paula [Saanio and Riekkola Oy, Helsinki (Finland)

    2006-09-15

    The main objectives of this report are to: 1) present density criteria considering deposition tunnels for the investigated backfill materials, 2) evaluate what densities can be achieved with the suggested backfill methods, 3) compare the density criteria to achievable densities, 4) based on this comparison evaluate the safety margin for the combinations of backfill materials and methods and, 5) make recommendations for further investigations and development work. The backfilling methods considered in this report are compaction of backfill material in situ in the tunnel and placement of pre-compacted blocks and pellets. The materials investigated in the second phase of the SKB-Posiva backfilling project can be divided into three main categories: 1. Bentonite clays: two high-grade Na-bentonites from Wyoming (MX-80 and SPV200), one low-grade bentonite from Kutch (India Asha 230), and one high and one low-grade Ca-bentonite from Milos (Deponite CA-N and Milos backfill). The high-grade bentonites are used in different bentonite-ballast mixtures. 2. Smectite-rich mixed-layer clays: one from Dnesice-Plzensko Jih (DPJ) located in the Czech Republic and one from Northern Germany (Friedland clay). Mixtures of bentonite and ballast: Mixtures consisting of high-grade bentonite (0, 40 and 50 w-%) and crushed rock with different type of grain size distribution or sand. The relationships between dry densities and hydraulic conductivity, swelling pressure and compressibility in saturated state for these materials were investigated. Most of the tests were performed with a groundwater salinity of 3.5%. This salinity is comparable to sea water and can be expected to be at the high end of salinities occurring during the assessment period. The purpose of the investigations was to determine the dry densities required to meet the function indicator criteria. These densities are referred to as the density criteria. However throughout the assessment period a loss of material and thus

  13. Groundwater flow evaluation through backfilling materials of a surface coal mining site of Northeast Mexico

    Science.gov (United States)

    Gutierrez-Ojeda, C.; Martínez-Morales, M.; Ortíz-Flores, G.

    2013-05-01

    Surface coal mining at the Allende-Piedras Negras aquifer system requires the complete dewatering and removal of the aquifer. The aquifer contains several geologic layers of variable hydraulic conductivity. Backfilling material is composed of a mixture of permeable and impermeable layers and it was initially considered as impermeable. Exploratory drillings, pumping tests and a geophysical survey were performed in the backfilling materials and the surrounding unaltered materials in order to evaluate the natural groundwater flow modification due to the mining activities. Results of geophysical survey evidenced a saturated water table within the back filling material which was verified by exploratory drilling. Pumping tests showed that unaltered materials have a mean hydraulic conductivity of 34.5 m/day while the backfilling of 5.3 m/day. Although the mining activities reduce the hydraulic conductivity by almost an order of magnitude, it was corroborated the existence of a groundwater flow through the backfilling materials.

  14. REQUIREMENT OF FLUIDITY OF HIGH WATER CONTENT MATERIALS FORTHE GETWAY-SIDE BACKFILLING TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    QiTaiyue; MaNianjie

    1996-01-01

    Through analyzing the effects of water consumption, diameter of solid particle, and flow velocity on the fluidity of high water content material slurry, the relationship among the fluidity, the isotropy of the slurry, and the pumping facilities applied in getway-side backfilling has been found. And the requirment of fluidity of high water content material for the design of getway-side backfilling technique is put forward in the paper.

  15. Experimental and numerical study of wave-induced backfilling beneath submarine pipelines

    DEFF Research Database (Denmark)

    Bayraktar, Deniz; Ahmad, Joseph; Eltard-Larsen, Bjarke;

    2016-01-01

    This paper presents results of complementary experimental and numerical studies involving wave-induced backfilling of current-generated scour holes beneath submarine pipelines. The laboratory experiments are conducted in a wave-plus-current flume, utilizing Laser Doppler Anemometry to measure...... utilizing a fully-coupled hydrodynamic and morphodynamic CFD model. The numerical simulations demonstrate the ability of the model to predict backfilling towards expected equilibrium scour depths based on the new wave climate, with time scales reasonably inline with experimental expectations....

  16. Experimental and Numerical Modeling of Seismic Earth Pressures on Retaining Walls with Cohesive Backfills

    OpenAIRE

    CANDIA, GABRIEL ALFONSO

    2013-01-01

    Observations from recent earthquakes show that all types of retaining structures with non-liquefiable backfills perform very well and there is limited evidence of damage or failures related to seismic earth pressures. Even retaining structures designed only for static loading have performed well during strong ground motions suggesting that special seismic design provisions may not be required in some cases. The objective of this study was to characterize the seismic interaction of backfill-wa...

  17. Effects of bituminous layer as backfill material on mechanical behavior in tunnel model

    OpenAIRE

    Moriyoshi, Akihiro; Takano, Shin-ei; Urata, Hiroyuki; Suzuki, Tetsuya; Yoshida, Takaki

    2001-01-01

    This paper describes the effects of bituminous material as a backfill material on mechanical behavior in model tunnel in laboratory. It is known that load spreading and relaxation of bituminous material are good properties. Then if we use bituminous material as a backfill material of tunnel, the tunnel will have waterproof, good load spreading property. We used new bituminous material (Aquaphalt) which can solidify in water. We conducted relaxation test in tension for new bituminous mat...

  18. Rheological Properties of Cemented Tailing Backfill and the Construction of a Prediction Model

    OpenAIRE

    Liu Lang; KI-IL Song; Dezheng Lao; Tae-Hyuk Kwon

    2015-01-01

    Workability is a key performance criterion for mining cemented tailing backfill, which should be defined in terms of rheological parameters such as yield stress and plastic viscosity. Cemented tailing backfill is basically composed of mill tailings, Portland cement, or blended cement with supplementary cement material (fly ash and blast furnace slag) and water, among others, and it is important to characterize relationships between paste components and rheological properties to optimize the w...

  19. Design, production and initial state of the backfill and plug in deposition tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Boerjesson, Lennart; Gunnarsson, David; Johannesson, Lars-Erik; Jonsson, Esther

    2010-12-15

    The report is included in a set of Production reports, presenting how the KBS-3 repository is designed, produced and inspected. The set of reports is included in the safety report for the KBS-3 repository and repository facility. The report provides input on the initial state of the backfill and plug in deposition tunnels for the assessment of the long-term safety, SR-Site. The initial state refers to the properties of the engineered barriers once they have been finally placed in the KBS-3 repository and will not be further handled within the repository facility. In addition, the report provides input to the operational safety report, SR-Operation, on how the backfill and plug shall be handled and installed. The report presents the design premises and reference designs of the backfill and plug in deposition tunnels and verifies their conformity to the design premises. It also describes the production of the backfill from excavation and delivery of backfill material to installation in the deposition tunnel, and gives an outline of the installation of the plug. Finally, the initial states of the backfill and plug and their conformity to the reference designs and design premises are presented

  20. Dessicant materials screening for backfill in a salt repository

    International Nuclear Information System (INIS)

    Maintaining an anhydrous environment around nuclear waste stored in a salt repository is a concern which can be alleviated by using a desiccant material for backfilling. Such a desiccant should desiccate a brine yet be non deliquescent, the hydrated product should have moderate thermal stability, and the desiccant should have a high capacity and be readily available. From a literature search MgO and CaO were identified for detailed study. These oxides, and an intimate mixture of the two obtained by calcining dolomite, were used in experiments to further determine their suitability. They proved to be excellent desiccants with a high water capacity. The hydrates of both have moderate thermal stability and a high water content. Both MgO and CaO react in an alkaline chloride brine forming oxychloride compounds with different waters of crystallization. Some of these compounds are the Sorel Cements. CaO hydrates to Ca(OH)2 which carbonates with CO2 in air to form CaCO3 and release the hydrated water. Thus the intimate mixture of CaO and MgO from calcined dolomite may serve as a desiccant and remove CO2 from the repository atmosphere

  1. Dessicant materials screening for backfill in a salt repository

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, D.R.

    1980-10-01

    Maintaining an anhydrous environment around nuclear waste stored in a salt repository is a concern which can be alleviated by using a desiccant material for backfilling. Such a desiccant should desiccate a brine yet be non deliquescent, the hydrated product should have moderate thermal stability, and the desiccant should have a high capacity and be readily available. From a literature search MgO and CaO were identified for detailed study. These oxides, and an intimate mixture of the two obtained by calcining dolomite, were used in experiments to further determine their suitability. They proved to be excellent desiccants with a high water capacity. The hydrates of both have moderate thermal stability and a high water content. Both MgO and CaO react in an alkaline chloride brine forming oxychloride compounds with different waters of crystallization. Some of these compounds are the Sorel Cements. CaO hydrates to Ca(OH)/sub 2/ which carbonates with CO/sub 2/ in air to form CaCO/sub 3/ and release the hydrated water. Thus the intimate mixture of CaO and MgO from calcined dolomite may serve as a desiccant and remove CO/sub 2/ from the repository atmosphere.

  2. 2D and 3D finite element analysis of buffer-backfill interaction

    International Nuclear Information System (INIS)

    Methods for backfilling and sealing of disposal tunnels in an underground repository for spent nuclear fuel are studied in cooperation between Finland (Posiva Oy) and Sweden (Svensk Kaernbraenslehantering AB, SKB) in 'BAckfilling and CLOsure of the deep repository' (Baclo) programme. Baclo phase III included modelling task force SP1: Finite element modelling of deformation of the backfill due to swelling of the buffer. The objective of the finite element modelling of the backfill was to study the interaction between the buffer and backfilling. The calculations aimed to find out how large deformations can happen in the buffer-backfill interface causing loosening of the buffer bentonite above the canister. The criterion used was that the saturated density of the buffer right above the canister should be higher than 1990 kg/m3. This report presents the results of finite element numerical analyses carried out by Wesi Geotecnica Srl. The modelling calculations were conducted with the so-called OL1-2 deposition tunnel geometry (Juvankoski 2009). Several parameters have been considered, varying from geometry variations to different mechanical constitutive models for different components of the model. In all analyses it has been assumed that the buffer material is fully saturated, thus exerting the isotropic swelling pressure estimated in the range 7 MPa .. 15 MPa, against a fully-dry backfill, which is no doubt the 'worst case scenario' with the highest risk to lead in decrease in dry density of the buffer. Friedland clay has been considered for backfill blocks and 30/70 mixture for foundation bed on which backfill blocks are installed. Preliminarily, finite element analyses have been performed with newly released PLAXIS 2D 2010 within the assumption of axial symmetry, the purpose of this first set of calculations being the evaluation of most relevant parameters influencing the deformations of buffer material. Hence, full 3D calculations have been performed with PLAXIS 3D

  3. Optimization of backfill pellet properties AASKAR DP2-Laboratory tests

    International Nuclear Information System (INIS)

    Bentonite pellets are planned to be used as a part of the backfill in the Swedish spent nuclear fuel deep repository concept KBS-3. This report describes testing and evaluation of different backfill pellet candidates. The work completed included testing of both pellet material and pellet type. The materials tested were sourced from India (ASHA), Greece (IBECO, 2 products) and Wyoming USA (MX-80 clay). The majority of the tests were completed on the ASHA clay as well as the IBECO-RWC-BF products, with only limited testing of the others. The pellets tested were manufactured using both extrusion and roller compaction techniques and had different sizes and geometries. The following tests have been performed and are presented in this report: 1. General tests. Water content, bulk density and dry density have been determined for both the pellet filling and the individual pellets. The compressibility of the pellet filling was tested with CRS-tests and the strength of the individual pellets was tested with a special compression test. The water content varied from 11.3% to 18.7% and was highest for the extruded pellets. The dry density was somewhat higher for the roller-compacted pellets and their compressibility was lower. The strength of the individual pellets was generally higher for the extruded pellets. 2. Erosion. The pellet filling will be exposed to groundwater inflow when installed in the tunnel. This flow could possibly cause significant erosion on the pellet filling. Erosion tests have been performed with comparisons in erosion resistance made on the various material- and pellet-types. The influence of variations in water salinity and flow rates was also tested. The IBECO extruded 6- and 10- mm diameter rods and the compacted Posiva spec.-A pellet filling seem to have the lowest tendency to erode. It is also the IBECO extruded pellet filling that withstands variations in water salinity and flow rates best. 3. Water storing capacity. The pellet filling's ability to

  4. Optimization of backfill pellet properties AASKAR DP2 - Laboratory tests

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Linus; Sanden, Torbjoern [Clay Technology AB, Lund (Sweden)

    2012-12-15

    Bentonite pellets are planned to be used as a part of the backfill in the Swedish spent nuclear fuel deep repository concept KBS-3. This report describes testing and evaluation of different backfill pellet candidates. The work completed included testing of both pellet material and pellet type. The materials tested were sourced from India (ASHA), Greece (IBECO, 2 products) and Wyoming USA (MX-80 clay). The majority of the tests were completed on the ASHA clay as well as the IBECO-RWC-BF products, with only limited testing of the others. The pellets tested were manufactured using both extrusion and roller compaction techniques and had different sizes and geometries. The following tests have been performed and are presented in this report: 1. General tests. Water content, bulk density and dry density have been determined for both the pellet filling and the individual pellets. The compressibility of the pellet filling was tested with CRS-tests and the strength of the individual pellets was tested with a special compression test. The water content varied from 11.3% to 18.7% and was highest for the extruded pellets. The dry density was somewhat higher for the roller-compacted pellets and their compressibility was lower. The strength of the individual pellets was generally higher for the extruded pellets. 2. Erosion. The pellet filling will be exposed to groundwater inflow when installed in the tunnel. This flow could possibly cause significant erosion on the pellet filling. Erosion tests have been performed with comparisons in erosion resistance made on the various material- and pellet-types. The influence of variations in water salinity and flow rates was also tested. The IBECO extruded 6- and 10- mm diameter rods and the compacted Posiva spec.-A pellet filling seem to have the lowest tendency to erode. It is also the IBECO extruded pellet filling that withstands variations in water salinity and flow rates best. 3. Water storing capacity. The pellet filling

  5. Vertical transportation system of solid material for backfilling coal mining technology

    Institute of Scientific and Technical Information of China (English)

    Ju Feng; Zhang Jixiong; Zhang Qiang

    2012-01-01

    For transportation of solid backfill material such as waste and fly ash from the surface to the bottom of the shaft in a fully mechanized backfilling coal backfilling coal mining technology,we developed a new vertical transportation system to transport this type of solid backfill material.Given the demands imposed on safely in feeding this material,we also investigated the structure and basic parameter of this system.For a mine in the Xingtai mining area the results show that:(1) a vertical transportation system should include three main parts,i.e.,a feeding borehole,a maintenance chamber and a storage silo; (2) we determined that 486 mm is a suitable diameter for bore holes,the diameter of the storage silo is 6 m and its height 30 m in this vertical transportation system; (3) a conical buffer was developed to absorb the impact during the feeding process.To ensure normal implementation of fully mechanized backfilling coal mining technology and the safety of underground personnel,we propose a series of security technologies for anti-blockage,storage silo cleaning.high pressure air release and aspiration.This vertical transporting system has been applied in one this particular mine,which has fed about 4 million tons solid material with a feeding depth of 350 m and safely exploited 3 million tons of coal.

  6. Effect of localized water uptake on backfill hydration and water movement in a backfilled tunnel: half-scale tests at Aespoe Bentonite Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, D. [Atomic Energy of Canada Limited, Chalk River (Canada); Jonsson, E. [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Hansen, J. [Posiva Oy, Olkiluoto (Finland); Hedin, M. [Aangpannefoereningen, Stockholm (Sweden); Ramqvist, G. [Eltekno AB, Figeholm (Sweden)

    2011-04-15

    The report describes the outcome of the work within the project 'SU508.20 Impact of water inflow in deposition tunnels'. Project decision SKB doc 1178871 Version 3.0. Two activity plans have been used for the field work: AP TD SU50820-09-019 and AP TD SU 50820-09-071. SKB and Posiva have been examining those processes that may have particularly strong effects on the evolution of a newly backfilled deposition tunnel in a KBS-3V repository. These assessments have involved the conduct of increasingly large and complex laboratory tests and simulations of a backfilled tunnel section. In this series of four tests, the effect of water inflow into a backfilled tunnel section via an intersecting fracture feature was evaluated. The tests included the monitoring of mock-ups where water entered via the simulated fractures as well as evaluation of what the effect of isolated tunnel sections caused by localized water inflow would have on subsequent evolution of these isolated sections. It was found that even a slowly seeping fracture can have a substantial effect on the backfill evolution as it will cause development of a gasket-like feature that effectively cuts of air and water movement from inner to outer regions of the backfilled tunnel. Water entering via these fractures will ultimately move out of the tunnel via a single discrete flow path, in a manner similar to what was observed in previous 1/2-scale and smaller simulations. If the low-rate of water inflow from fracture is the only source of water inflow to the tunnel this will result in hydraulic behaviour similar to that observed for a single inflow point in previous tests. The presence of a fracture feature will however result in a larger proportion of water uptake by the process of suction than might occur in a point inflow situation and hence a more uniform water distribution will be present in the pellet fill. This also results in a greater tendency for water to be absorbed into the adjacent block fill

  7. Study on Key Technology of Using Shell Sand as Backfill for Sea Reclamation

    Institute of Scientific and Technical Information of China (English)

    LI Neng-hui; QU Yi-rong; HE Wen-qin; CHEN Hui

    2005-01-01

    The results of a study on the key technology of using shell sand, a kind of sea sand, as backfill for sea reclamation are described briefly. Laboratory tests show that the physical and mechanical properties of shell sand are as good as normal quartz sand. Based on the chemical test and durability test of shell sand it could be concluded that the influence of corrosion of shell sand by acid rain and sea water might be ignored in the evaluation of the safety and durability of the engineering project. The results of field improvement tests show that the bearing capacity of shell sand backfill foundation is more than 200 kPa after vibroflotation improvement or dynamic compaction improvement. The shell sand is a good backfill material for sea reclamation.

  8. Valorization of mining waste and tailings through paste backfilling solution, Imiter operation, Morocco

    Institute of Scientific and Technical Information of China (English)

    Khaldoun Abdelhadi; Ouadif Latifa; Baba Khadija; Bahi Lahcen

    2016-01-01

    Mine waste and process tailings storage is one of important challenge for which mining operations are increasingly confronted. Treatment discharges of plants and main part of waste rock development are generally stored on surface areas. The volume and chemical characteristics of these materials generate serious problem for required storage spaces and mainly environmental degradation. Paste backfill (PBF) is one of ingenious solutions to minimize the quantity of tailings to store. PBF is basically defined as a combination of mine processing tailings, binder, and water mixing. The purpose of this paper is to present backfilling components characterization and formula verification for a waste valorization solu-tion through paste backfilling technology in Imiter operation. Obtained results and realized analysis demonstrate PBF conformity and adequacy with assigned underground functions. However the studied recipe can be more ameliorated to obtain an optimal mixture ensuring the required mechanical strength.

  9. Stability analysis of backfilling in subsiding area and optimization of the stoping sequence

    Institute of Scientific and Technical Information of China (English)

    Ping Wang; Huiqiang Li; Yan Li; Bo Chen

    2013-01-01

    In underground mining by sublevel caving method, the deformation and damage of the surface induced by subsidence are the major challenging issues. The dynamic and soft backfilling body increases the safety risks in the subsiding area. In this paper, taking Zhangfushan iron mine as an example, the ore body and the general layout are focused on the safety of backfilling of mined-out area. Then, we use the ANSYS software to construct a three-dimensional (3D) model for the mining area in the Zhangfushan iron mine. According to the simulation results of the initial mining stages, the ore body is stoped step by step as suggested in the design. The stability of the backfilling is back analyzed based on the monitored displacements, considering the stress distribution to optimize the stoping sequence. The simulations show that a reasonable stoping sequence can minimize the concentration of high compressive stress and ensure the safety of stoping of the ore body.

  10. Backfilling of a Scour Hole around a Pile in Waves and Current

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Petersen, Thor Ugelvig; Locatelli, Luca;

    2013-01-01

    This paper presents the results of an experimental investigation of the backfilling of scour holes around circular piles. Scour holes around a pile are generated either by a current or a wave. Subsequently, the flow climate is changed from current to wave, combined waves and current, or wave...... around the pile for the same wave (or combined waves and current) climate. The time scale of backfilling has been determined as a function of three parameters, namely, (1) the Keulegan-Carpenter number of the initial wave or current (which generates the initial scour hole); (2) that of the subsequent...

  11. Roadway backfill method to prevent geo-hazards induced by room and pillar mining: a case study in Changxing coal mine, China

    OpenAIRE

    Zhang, Jixiong; Li, Meng; Zhou, Nan; Gao, Rui

    2016-01-01

    Coal mines in the western areas of China experience low mining rates and induce many geo-hazards when using the room and pillar mining method. In this research, we proposed a roadway backfill method during longwall mining to target these problems. We tested the mechanical properties of the backfill materials to determine a reasonable ratio of backfill materials for the driving roadway during longwall mining. We also introduced the roadway layout and the backfill mining technique required for ...

  12. Efficacy of backfilling and other engineered barriers in a radioactive waste repository in salt

    Energy Technology Data Exchange (ETDEWEB)

    Claiborne, H.C.

    1982-09-01

    In the United States, investigation of potential host geologic formations was expanded in 1975 to include hard rocks. Potential groundwater intrusion is leading to very conservative and expensive waste package designs. Recent studies have concluded that incentives for engineered barriers and 1000-year canisters probably do not exist for reasonable breach scenarios. The assumption that multibarriers will significantly increase the safety margin is also questioned. Use of a bentonite backfill for surrounding a canister of exotic materials was developed in Sweden and is being considered in the US. The expectation that bentonite will remain essentially unchanged for hundreds of years for US repository designs may be unrealistic. In addition, thick bentonite backfills will increase the canister surface temperature and add much more water around the canister. The use of desiccant materials, such as CaO or MgO, for backfilling seems to be a better method of protecting the canister. An argument can also be made for not using backfill material in salt repositories since the 30-cm-thick space will provide for hole closure for many years and will promote heat transfer via natural convection. It is concluded that expensive safety systems are being considered for repository designs that do not necessarily increase the safety margin. It is recommended that the safety systems for waste repositories in different geologic media be addressed individually and that cost-benefit analyses be performed.

  13. Fluid transport along gutta-percha backfills with and without sealer

    NARCIS (Netherlands)

    Wu, MK; van der Sluis, LWM; Wesselink, PR

    2004-01-01

    Objective. The use of heat may influence the sealing ability of sealer. The aim of this study was to compare the fluid transport along the gutta-percha backfill portion when different sealers were used or no sealer at all. Study design. Four groups consisting of the roots of maxillary and mandibular

  14. Buffer, backfill and closure process report for the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    Sellin, Patrik (ed.)

    2010-11-15

    This report gives an account of how processes in buffer, deposition tunnel backfill and the closure important for the long-term evolution of a KBS-3 repository for spent nuclear fuel, will be documented in the safety assessment SR-Site

  15. Efficacy of backfilling and other engineered barriers in a radioactive waste repository in salt

    International Nuclear Information System (INIS)

    In the United States, investigation of potential host geologic formations was expanded in 1975 to include hard rocks. Potential groundwater intrusion is leading to very conservative and expensive waste package designs. Recent studies have concluded that incentives for engineered barriers and 1000-year canisters probably do not exist for reasonable breach scenarios. The assumption that multibarriers will significantly increase the safety margin is also questioned. Use of a bentonite backfill for surrounding a canister of exotic materials was developed in Sweden and is being considered in the US. The expectation that bentonite will remain essentially unchanged for hundreds of years for US repository designs may be unrealistic. In addition, thick bentonite backfills will increase the canister surface temperature and add much more water around the canister. The use of desiccant materials, such as CaO or MgO, for backfilling seems to be a better method of protecting the canister. An argument can also be made for not using backfill material in salt repositories since the 30-cm-thick space will provide for hole closure for many years and will promote heat transfer via natural convection. It is concluded that expensive safety systems are being considered for repository designs that do not necessarily increase the safety margin. It is recommended that the safety systems for waste repositories in different geologic media be addressed individually and that cost-benefit analyses be performed

  16. Evaluation of the effect of sodium silicate addition to mine backfill, Gelfill − Part 1

    Directory of Open Access Journals (Sweden)

    M. Kermani

    2015-06-01

    Full Text Available In this paper, the mechanical properties of sodium silicate-fortified backfill, called Gelfill, were investigated by conducting a series of laboratory experiments. Two configurations were tested, i.e. Gelfill and cemented hydraulic fill (CHF. The Gelfill has an alkali activator such as sodium silicate in its materials in addition to primary materials of mine backfill which are tailings, water and binders. Large numbers of samples of Gelfill and CHF with various mixture designs were cast and cured for over 28 d. The mechanical properties of samples were investigated using uniaxial compression test, and the results were compared with those of reference samples made without sodium silicate. The test results indicated that the addition of an appropriate amount of an alkali activator such as sodium silicate can enhance the mechanical (uniaxial compressive strength and physical (water retention properties of backfill. The microstructure analysis conducted by mercury intrusion porosimetry (MIP revealed that the addition of sodium silicate can modify the pore size distribution and total porosity of Gelfill, which can contribute to the better mechanical properties of Gelfill. It was also shown that the time and rate of drainage in the Gelfill specimens are less than those in CHF specimens made without sodium silicate. Finally, the study showed that the addition of sodium silicate can reduce the required setting time of mine backfill, which can contribute to increase mine production in accordance with the mine safety.

  17. Evaluation of the effect of sodium silicate addition to mine backfill, Gelfill L Part 1

    Institute of Scientific and Technical Information of China (English)

    M. Kermani; F.P. Hassani; E. Aflaki; M. Benzaazoua; M. Nokken

    2015-01-01

    In this paper, the mechanical properties of sodium silicate-fortified backfill, called Gelfill, were investi-gated by conducting a series of laboratory experiments. Two configurations were tested, i.e. Gelfill and cemented hydraulic fill (CHF). The Gelfill has an alkali activator such as sodium silicate in its materials in addition to primary materials of mine backfill which are tailings, water and binders. Large numbers of samples of Gelfill and CHF with various mixture designs were cast and cured for over 28 d. The me-chanical properties of samples were investigated using uniaxial compression test, and the results were compared with those of reference samples made without sodium silicate. The test results indicated that the addition of an appropriate amount of an alkali activator such as sodium silicate can enhance the mechanical (uniaxial compressive strength) and physical (water retention) properties of backfill. The microstructure analysis conducted by mercury intrusion porosimetry (MIP) revealed that the addition of sodium silicate can modify the pore size distribution and total porosity of Gelfill, which can contribute to the better mechanical properties of Gelfill. It was also shown that the time and rate of drainage in the Gelfill specimens are less than those in CHF specimens made without sodium silicate. Finally, the study showed that the addition of sodium silicate can reduce the required setting time of mine backfill, which can contribute to increase mine production in accordance with the mine safety.

  18. The Community project on engineering aspects of backfilling and sealing of radioactive waste repositories

    International Nuclear Information System (INIS)

    This report summarizes the work carried out under CEC contracts about engineering aspects of backfilling and sealing of radioactive waste repositories, for the time period 1983-84. It complements a previous report (ref. EUR 9283) on the same topic, this latter covering the period 1980-82

  19. UNDERGROUNG PLACEMENT OF COAL PROCESSING WASTE AND COAL COMBUSTION BY-PRODUCTS BASED PASTE BACKFILL FOR ENHANCED MINING ECONOMICS

    Energy Technology Data Exchange (ETDEWEB)

    Y.P. Chugh; D. Biswas; D. Deb

    2002-06-01

    This project has successfully demonstrated that the extraction ratio in a room-and-pillar panel at an Illinois mine can be increased from the current value of approximately 56% to about 64%, with backfilling done from the surface upon completion of all mining activities. This was achieved without significant ground control problems due to the increased extraction ratio. The mined-out areas were backfilled from the surface with gob, coal combustion by-products (CCBs), and fine coal processing waste (FCPW)-based paste backfill containing 65%-70% solids to minimize short-term and long-term surface deformations risk. This concept has the potential to increase mine productivity, reduce mining costs, manage large volumes of CCBs beneficially, and improve the miner's health, safety, and environment. Two injection holes were drilled over the demonstration panel to inject the paste backfill. Backfilling was started on August 11, 1999 through the first borehole. About 9,293 tons of paste backfill were injected through this borehole with a maximum flow distance of 300-ft underground. On September 27, 2000, backfilling operation was resumed through the second borehole with a mixture of F ash and FBC ash. A high-speed auger mixer (new technology) was used to mix solids with water. About 6,000 tons of paste backfill were injected underground through this hole. Underground backfilling using the ''Groutnet'' flow model was simulated. Studies indicate that grout flow over 300-foot distance is possible. Approximately 13,000 tons of grout may be pumped through a single hole. The effect of backfilling on the stability of the mine workings was analyzed using SIUPANEL.3D computer program and further verified using finite element analysis techniques. Stiffness of the backfill mix is most critical for enhancing the stability of mine workings. Mine openings do not have to be completely backfilled to enhance their stability. Backfill height of about 50% of the seam

  20. Development and validation of a CFD model predicting the backfill process of a nuclear waste gallery

    Energy Technology Data Exchange (ETDEWEB)

    Gopala, Vinay Ramohalli, E-mail: gopala@nrg.eu [Nuclear Research and consultancy Group (NRG), P.O. Box 25, 1755 ZG Petten (Netherlands); Lycklama a Nijeholt, Jan-Aiso [Nuclear Research and consultancy Group (NRG), P.O. Box 25, 1755 ZG Petten (Netherlands); Bakker, Paul [Van Hattum en Blankevoort, Woerden (Netherlands); Haverkate, Benno [Nuclear Research and consultancy Group (NRG), P.O. Box 25, 1755 ZG Petten (Netherlands)

    2011-07-15

    Research highlights: > This work presents the CFD simulation of the backfill process of Supercontainers with nuclear waste emplaced in a disposal gallery. > The cement-based material used for backfill is grout and the flow of grout is modelled as a Bingham fluid. > The model is verified against an analytical solution and validated against the flowability tests for concrete. > Comparison between backfill plexiglas experiment and simulation shows a distinct difference in the filling pattern. > The numerical model needs to be further developed to include segregation effects and thixotropic behavior of grout. - Abstract: Nuclear waste material may be stored in underground tunnels for long term storage. The example treated in this article is based on the current Belgian disposal concept for High-Level Waste (HLW), in which the nuclear waste material is packed in concrete shielded packages, called Supercontainers, which are inserted into these tunnels. After placement of the packages in the underground tunnels, the remaining voids between the packages and the tunnel lining is filled-up with a cement-based material called grout in order to encase the stored containers into the underground spacing. This encasement of the stored containers inside the tunnels is known as the backfill process. A good backfill process is necessary to stabilize the waste gallery against ground settlements. A numerical model to simulate the backfill process can help to improve and optimize the process by ensuring a homogeneous filling with no air voids and also optimization of the injection positions to achieve a homogeneous filling. The objective of the present work is to develop such a numerical code that can predict the backfill process well and validate the model against the available experiments and analytical solutions. In the present work the rheology of Grout is modelled as a Bingham fluid which is implemented in OpenFOAM - a finite volume-based open source computational fluid dynamics

  1. Development and validation of a CFD model predicting the backfill process of a nuclear waste gallery

    International Nuclear Information System (INIS)

    Research highlights: → This work presents the CFD simulation of the backfill process of Supercontainers with nuclear waste emplaced in a disposal gallery. → The cement-based material used for backfill is grout and the flow of grout is modelled as a Bingham fluid. → The model is verified against an analytical solution and validated against the flowability tests for concrete. → Comparison between backfill plexiglas experiment and simulation shows a distinct difference in the filling pattern. → The numerical model needs to be further developed to include segregation effects and thixotropic behavior of grout. - Abstract: Nuclear waste material may be stored in underground tunnels for long term storage. The example treated in this article is based on the current Belgian disposal concept for High-Level Waste (HLW), in which the nuclear waste material is packed in concrete shielded packages, called Supercontainers, which are inserted into these tunnels. After placement of the packages in the underground tunnels, the remaining voids between the packages and the tunnel lining is filled-up with a cement-based material called grout in order to encase the stored containers into the underground spacing. This encasement of the stored containers inside the tunnels is known as the backfill process. A good backfill process is necessary to stabilize the waste gallery against ground settlements. A numerical model to simulate the backfill process can help to improve and optimize the process by ensuring a homogeneous filling with no air voids and also optimization of the injection positions to achieve a homogeneous filling. The objective of the present work is to develop such a numerical code that can predict the backfill process well and validate the model against the available experiments and analytical solutions. In the present work the rheology of Grout is modelled as a Bingham fluid which is implemented in OpenFOAM - a finite volume-based open source computational fluid

  2. Colloids in the mortar backfill of a cementitious repository for radioactive waste.

    Science.gov (United States)

    Wieland, E; Spieler, P

    2001-01-01

    Colloids are present in groundwater aquifers and water-permeable engineered barrier systems and may facilitate the migration of radionuclides. A highly permeable mortar is foreseen to be used as backfill for the engineered barrier of the Swiss repository for low- and intermediate-level waste. The backfill is considered to be a chemical environment with some potential for colloid generation and, due to its high porosity, for colloid mobility. Colloid concentration measurements were carried out using an in-situ liquid particle counting system. The in-house developed counting system with three commercially available sensors allowed the detection of single particles and colloids at low concentrations in the size range 50-5000 nm. The counting system was tested using suspensions prepared from certified size standards. The concentrations of colloids with size range 50-1000 nm were measured in cement pore water, which was collected from a column filled with a highly permeable backfill mortar. The chemical composition of the pore water corresponded to a Ca(OH)2-controlled cement system. Colloid concentrations in the backfill pore water were found to be typically lower than approximately 0.1 ppm. The specific (geometric) surface areas of the colloid populations were in the range 240 m2 g(-1) to 770 m2 g(-1). The low colloid inventories observed in this study can be explained by the high ionic strength and Ca concentrations of the cement pore water. These conditions are favourable for colloid-colloid and colloid-backfill interactions and unfavourable for colloid-enhanced nuclide transport.

  3. Paste-like self-flowing transportation backfilling technology based on coal gangue

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-min; ZHAO Bin; ZHANG Chuan-shu; ZHANG Qin-li

    2009-01-01

    A paste-like self-flowing pipeline transportation backfilling technology with coal gangue as aggregate is proposed to remove the potential damage caused by coal gangue piles. As well, the difficult problems of recovering high quality safety coal pillars and deep mining of the Suncun Coal Mine (SCM), Xinwen Coal Group, Shandong are resolved. The physical-chemical properties of coal gangue, optimized proportion of materials, backfilling system and craft in the SCM were studied in the laboratory and then an industrial test was carried out on high quality coal pillars under a town. The results show that finely crushed kaolinized and fresh gangue with granularity less than 5 mm can be used as aggregate with fly ash to replace part of the cement and a compos-ite water reducer as an additive, accounting for 1.0%-1.5% of the total amount of cement and fly ash. The recommended proportion is I(cement):4(fly ash): 15(coal gangue), with a mass fraction of 72%-75%, theological paste-like properties and a strength of more than 0.7 MPa at 7 d. The sequence of adding cement, fly ash, water reducer and then coal gangue ensures that the suspended state of the slurry, reducing the wear and jam of pipelines. The working face is advancing continuously by the alternating craft of building block walls with coal gangue and backfilling mined-out gobs with paste-like slurry. The recovery rate is as high as 90% with a backfilling cost of 36.9 Yuan/t, good utilization of coal gangue and no subsidence on the surface. This technology provides a good theoretical basis and application experience for coal mines, cement backfilling with paste-like slurry.

  4. Development of backfill material as an engineered barrier in the waste package system. Interim topical report

    International Nuclear Information System (INIS)

    A backfill barrier, emplaced between the containerized waste and the host rock, can both protect the other engineered barriers and act as a primary barrier to the release of radionuclides from the waste package. Attributes that a backfill should provide in order to carry out its required function have been identified. Primary attributes are those that have a direct effect upon the release and transport of radionuclides from the waste package. Supportive attributes do not directly affect radionuclide release but are necessary to support the primary attributes. The primary attributes, in order of importance, are: minimize (retard or exclude) the migration of ground water between the host rock and the waste canister system; retard the migration of selected chemical species (corrosive species and radionuclides) in the ground water; control the Eh and pH of the ground water within the waste-package environment. The supportive attributes are: self-seal any cracks or discontinuities in the backfill or interfacing host geology; retain performance properties at all repository temperatures; retain peformance properties during and after receiving repository levels of gamma radiation; conduct heat from the canister system to the host geology; retain mechanical properties and provide resistance to applied mechanical forces; retain morphological stability and compatibility with structural barriers and with the host geology for required period of time. Screening and selection of candidate backfill materials has resulted in a preliminary list of materials for testing. Primary emphasis has been placed on sodium and calcium bentonites and zeolites used in conjunction with quartz sand or crushed host rock. Preliminary laboratory studies have concentrated on permeability, sorption, swelling pressure, and compaction properties of candidate backfill materials

  5. Rheological Properties of Cemented Tailing Backfill and the Construction of a Prediction Model

    Directory of Open Access Journals (Sweden)

    Liu Lang

    2015-04-01

    Full Text Available Workability is a key performance criterion for mining cemented tailing backfill, which should be defined in terms of rheological parameters such as yield stress and plastic viscosity. Cemented tailing backfill is basically composed of mill tailings, Portland cement, or blended cement with supplementary cement material (fly ash and blast furnace slag and water, among others, and it is important to characterize relationships between paste components and rheological properties to optimize the workability of cemented tailing backfill. This study proposes a combined model for predicting rheological parameters of cemented tailing backfill based on a principal component analysis (PCA and a back-propagation (BP neural network. By analyzing experimental data on mix proportions and rheological parameters of cemented tailing backfill to determine the nonlinear relationships between rheological parameters (i.e., yield stress and viscosity and mix proportions (i.e., solid concentrations, the tailing/cement ratio, the specific weight, and the slump, the study constructs a prediction model. The advantages of the combined model were as follows: First, through the PCA, original multiple variables were represented by two principal components (PCs, thereby leading to a 50% decrease in input parameters in the BP neural network model, which covered 98.634% of the original data. Second, in comparison to conventional BP neural network models, the proposed model featured a simpler network architecture, a faster training speed, and more satisfactory prediction performance. According to the test results, any error between estimated and expected output values from the combined prediction model based on the PCA and the BP neural network was within 5%, reflecting a remarkable improvement over results for BP neural network models with no PCA.

  6. The simplified convergence rate calculation for salt grit backfilled caverns in rock salt

    International Nuclear Information System (INIS)

    Within the research and development project 3609R03210 of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, different methods were investigated, which are used for the simplified calculation of convergence rates for mining cavities in salt rock that have been backfilled with crushed salt. The work concentrates on the approach of Stelte and on further developments based on this approach. The work focuses on the physical background of the approaches. Model specific limitations are discussed and possibilities for further development are pointed out. Further on, an alternative approach is presented, which implements independent material laws for the convergence of the mining cavity and the compaction of the crushed salt backfill.

  7. Numerical simulation of wave-induced scour and backfilling processes beneath submarine pipelines

    DEFF Research Database (Denmark)

    Fuhrman, David R.; Baykal, Cüneyt; Sumer, B. Mutlu;

    2014-01-01

    A fully-coupled hydrodynamic/morphodynamic numerical model is presented and utilized for the simulation of wave-induced scour and backfilling processes beneath submarine pipelines. The model is based on solutions to Reynolds-averaged Navier–Stokes equations, coupled with k−ω turbulence closure......, with additional bed and suspended load descriptions forming the basis for sea bed morphology. The morphological evolution is updated continuously, rather than being based e.g. on period- or other time-averaging techniques. Simulations involving wave-induced scour over the range of Keulegan–Carpenter number 5.6≤KC......≤30 demonstrate reasonable match with previous experiments, both in terms of the equilibrium scour depth as well as the scour time scale. Wave-induced backfilling processes are additionally studied by subjecting initial conditions taken from scour simulations with larger KC to new wave climates...

  8. A mathematical model of the behaviour of concrete backfill in an underground waste repository

    International Nuclear Information System (INIS)

    This report concerns the mathematical modelling by the finite element method of the behaviour of concrete, one of the candidate materials for use in the backfilling and sealing of underground repositories for radioactive waste. The present study is predominantly concerned with the development of a mathematical model for use within the ADINA finite element code to predict the time-dependent performance of concrete as a backfilling and sealing material. The finite element material model developed accounts for the ageing of concrete, multi-axial creep and creep recovery, the effect of external environmental humidity and changing internal temperatures. The model compares favourably with available published experimental data for maturing concrete but requires considerable further validation against a wider range of experimental results. (author)

  9. EXPERIMENTAL AND NUMERICAL INVESTIGATION OF FLEXIBLE BURIED PIPE DEFORMATION BEHAVIOR UNDER VARIOUS BACKFILL CONDITIONS

    OpenAIRE

    TERZİ, Niyazi Uğur; Sönmez YILDIRIM

    2009-01-01

    Deformation characteristics of polyethylene based flexible pipes are different than rigid pipes such as concrete and iron pipes. Deflection patterns and stress-strain behaviors of flexible pipes have strict relation between the engineering properties of backfill and its settlement method. In this study, deformation behavior of a 100 mm HDPE flexible pipe under vertical loads is investigated in laboratory conditions. Steel test box, pressurized membrane, raining system, linear position transdu...

  10. Retardation of radionuclides in back-fill materials of TVO VLJ repository and in rocks

    International Nuclear Information System (INIS)

    Retardation and diffusion in rock and rock-bentonite back-fill of the following reactor waste elements are reviewed: carbon, cobalt, nickel, strontium, technetium, iodine, cesium, plutonium and americium. Such conservative values for distribution coefficients and diffusion coefficients are proposed for the use in safety assessment of the final disposal of the waste that they lead to overestimations in biosphere radiation doses. Also more realistic values are proposed

  11. Paste backfill of shallow mine workings for land reclamation in Canmore, Alberta

    International Nuclear Information System (INIS)

    The coal mining history in Canmore, Alberta was presented along with reclamation activities that mine regulators carried out following closure of the mines after nearly 100 years of underground mining. The 7 seams that were mined commercially extend over distances of a few hundred feet and have been displaced by faults. Voids and collapsed rubble in shallow underground workings pose a risk of potential ground subsidence that can affect the stability of surface structures and infrastructure, including the planned development of the proposed Three Sisters Mountain Village on land above the abandoned mines. The village includes plans for 10,000 residential homes, 2 golf courses, and a resource centre. A mine works mitigation program involved drilling primary injection boreholes on a 15 m grid pattern to map the constraint zones in order to gain a better perspective of the subsidence issues as well as the effects of subsidence on structural stress and public safety. When determining mitigation criteria, various land uses and ranges of subsidence hazards were considered to be compatible with each land use. A paste backfill composed of aggregate from a locally available till overburden site was mixed with cement and injected into the void spaces. This paper described the cemented paste backfill injection method; confirmatory methods; maximum volume and pressure criteria; survey for ground uplift; and borehole camera and manual checks for cemented paste backfill in adjacent boreholes. Quality control testing was carried out by means of slump tests. It was concluded that cemented paste backfill mix could be used successfully to stabilize abandoned mine workings for land recovery. 8 refs., 5 tabs., 7 figs

  12. Use of inorganic sorbents for treatment of liquid radioactive waste and backfill of underground repositories

    International Nuclear Information System (INIS)

    This document presents the results of a four year Co-ordinated Research Programme (CRP) on the ''Use of Inorganic Sorbents for Treatment of Liquid Radioactive Waste and Backfill of Underground Repositories'' (1987-1991). Many countries have research programmes aiming at developing processes which would provide efficient and safe concentration of radionuclides in waste streams into solid materials which could then be reliably immobilized into forms suitable for long term storage or disposal. Use of inorganic sorbents for this purpose is very attractive because of their resistance to radiation and chemical attack, strong affinity for one or more radionuclides, their compatibility with likely immobilization matrices and their availability at low cost. According to the fundamental multibarrier concept for disposal of radioactive waste, backfill material is one of the important engineered barriers. Inorganic materials such as clays, naturally occurring zeolites (clinoptilolite, modenite and chabasite) are promising backfill materials. Research in technical uses of inorganic material applications was covered within the framework of the Co-ordinated Research Programme reported in this technical document. Final contributions by participants at the last Research Co-ordination Meeting held in Rez, Czechoslovakia, from 4 to 8 November 1991, are presented here. Refs, figs and tabs

  13. Development of a quantitative accelerated sulphate attack test for mine backfill

    Science.gov (United States)

    Shnorhokian, Shahe

    Mining operations produce large amounts of tailings that are either disposed of in surface impoundments or used in the production of backfill to be placed underground. Their mineralogy is determined by the local geology, and it is not uncommon to come across tailings with a relatively high sulphide mineral content, including pyrite and pyrrhotite. Sulphides oxidize in the presence of oxygen and water to produce sulphate and acidity. In the concrete industry, sulphate is known to produce detrimental effects by reacting with the cement paste to produce the minerals ettringite and gypsum. Because mine backfill uses tailings and binders---including cement---it is therefore prone to sulphate attack where the required conditions are met. Currently, laboratory tests on mine backfill mostly measure mechanical properties such as strength parameters, and the study of the chemical aspects is restricted to the impact of tailings on the environment. The potential of sulphate attack in mine backfill has not been studied at length, and no tests are conducted on binders used in backfill for their resistance to attack. Current ASTM guidelines for sulphate attack tests have been deemed inadequate by several authors due to their measurement of only expansion as an indicator of attack. Furthermore, the tests take too long to perform or are restricted to cement mortars only, and not to mixed binders that include pozzolans. Based on these, an accelerated test for sulphate attack was developed in this work through modifying and compiling procedures that had been suggested by different authors. Small cubes of two different binders were fully immersed in daily-monitored sodium sulphate and sulphuric acid solutions for a total of 28 days, after 7 days of accelerated curing at 50°C. In addition, four binders were partially immersed in the same solutions for 8 days for an accelerated attack process. The two procedures were conducted in tandem with leach tests using a mixed solution of

  14. Analysis on Backfill Mining of “Under Three” Coal in Zhouyuanshan Mine and Strata Movement Law

    Directory of Open Access Journals (Sweden)

    Weijian Yu

    2013-09-01

    Full Text Available In order to solve the problem of "under three" (under railways, buildings and water bodies coal pillar mining, analysis on backfill mining and strata movement law is carried on in 24 mining district of Zhouyuanshan coal mine. First of all, according to the engineering geology and strata occurrence condition in 24 mining district of Zhouyuanshan coal mine, FLAC2D software be used to establish a two-dimensional numerical model and to analyze and calculate the full caving method, strip method and backfill method and then gaining that backfill mining method is beneficial to improve the protection level of surface buildings and facilities. Then, using the theory of strata control and method of related mechanics to analyze the strata movement law and strata control principle of backfill mining, considering that supporting role of backfill body is mainly on lateral reinforcement of coal pillar and vertical supporting role of overlying strata, forming a cooperative control system of "bearing strata + coal pillar + backfill body" and deducing the equilibrium equations when it is in steady state. At last, using the numerical analysis method, respectively analyzing the surface subsidence of the corresponding important buildings of the three profiles of C-8 exploration line ,C-6 exploration line and A-A (cross section of the profile of C-8 exploration line after using backfill coal mining in 24 mining district. The results show that: the surface subsidence and horizontal deformation basically control within 30 mm and the surface deformation curvature of buildings generally in 0.1×10-3 /km in 24 mining district of Zhouyuanshan coal mine, which accord with the relevant standards and requirements.

  15. Direct shear tests on cemented paste backfill–rock wall and cemented paste backfill–backfill interfaces

    Directory of Open Access Journals (Sweden)

    Nabassé J.F. Koupouli

    2016-08-01

    Full Text Available This paper presents the results of the shear strength (frictional strength of cemented paste backfill-cemented paste backfill (CPB-CPB and cemented paste backfill–rock wall (CPB-rock interfaces. The frictional behaviors of these interfaces were assessed for the short-term curing times (3 d and 7 d using a direct shear apparatus RDS-200 from GCTS (Geotechnical Consulting & Testing Systems. The shear (friction tests were performed at three different constant normal stress levels on flat and smooth interfaces. These tests aimed at understanding the mobilized shear strength at the CPB-rock and CPB-CPB interfaces during and/or after open stope filling (no exposed face. The applied normal stress levels were varied in a range corresponding to the usually measured in-situ horizontal pressures (longitudinal or transverse developed within paste-filled stopes (uniaxial compressive strength, σc ≤ 150 kPa. Results show that the mobilized shear strength is higher at the CPB-CPB interface than that at the CPB-rock interface. Also, the perfect elastoplastic behaviors observed for the CPB-rock interfaces were not observed for the CPB-CPB interfaces with low cement content which exhibits a strain-hardening behavior. These results are useful to estimate or validate numerical model for pressures determination in cemented backfill stope at short term. The tests were performed on real backfill and granite. The results may help understanding the mechanical behavior of the cemented paste backfill in general and, in particular, analyzing the shear strength at backfill–backfill and backfill-rock interfaces.

  16. Deep repository - Engineered barrier system. Erosion and sealing processes in tunnel backfill materials investigated in laboratory

    International Nuclear Information System (INIS)

    SKB in Sweden and Posiva in Finland are developing and plan to implement similar disposal concepts for the final disposal of spent nuclear fuel. Co-operation and joint development work between Posiva and SKB with the overall objective to develop backfill concepts and techniques for sealing and closure of the repository have been going on for several years. The investigation described in this report is intended to acquire more knowledge regarding the behavior of some of the candidate backfilling materials. Blocks made of three different materials (Friedland clay, Asha 230 or a bentonite/ballast 30/70 mixture) as well as different bentonite pellets have been examined. The backfill materials will be exposed to an environment simulating that in a tunnel, with high relative humidity and water inflow from the rock. The processes and properties investigated are: 1. Erosion properties of blocks and pellets (Friedland blocks, MX-80 pellets, Cebogel QSE pellets, Minelco and Friedland granules). 2. Displacements of blocks after emplacement in a deposition drift (Blocks of Friedland, Asha 230 and Mixture 30/70). 3. The ability of these materials to seal a leaking in-situ cast plug cement/rock but also other fractures in the rock (MX-80 pellets). 4. The self healing ability after a piping scenario (Blocks of Friedland, Asha 230 Mixture 30/70 and also MX-80 pellets). 5. Swelling and cracking of the compacted backfill blocks caused by relative humidity. The erosion properties of Friedland blocks were also investigated in Phase 2 of the joint SKBPosiva project 'Backfilling and Closure of the Deep Repository, BACLO, which included laboratory scale experiments. In this phase of the project (3) some completing tests were performed with new blocks produced for different field tests. These blocks had a lower density than intended and this has an influence on the erosion properties measured. The erosion properties of MX-80 pellets were also investigated earlier in the project but an

  17. BEHAVIOUR OF BACKFILL MATERIALS FOR ELECTRICAL GROUNDING SYSTEMS UNDER HIGH VOLTAGE CONDITIONS

    Directory of Open Access Journals (Sweden)

    S. C. LIM

    2015-06-01

    Full Text Available Backfill materials like Bentonite and cement are effective in lowering grounding resistance of electrodes for a considerable period. During lightning, switching impulses and earth fault occurrences in medium and high voltage networks, the grounding system needs to handle extremely high currents either for a short duration or prolonged period respectively. This paper investigates the behaviour of bentonite, cement and sand under impulse and alternating high voltage (50Hz conditions. Fulguritic-formation was observed in all materials under alternating high voltage. The findings reveal that performance of grounding systems under high voltage conditions may significantly change from the outcomes anticipated at design stage.

  18. Backfill Mining Technology and Development Tendency in China Coal Mine%我国煤矿充填开采技术及其发展趋势

    Institute of Scientific and Technical Information of China (English)

    胡炳南

    2012-01-01

    Based on the requirements of the sustainable development and environment protection, the paper stated the necessity of the backfill mining in mine. With the collection and analysis on the application of 20 typical backfill mining faces in China, the paper systematically stated the technical features and suitable conditions of the mine roadway heading with the rejects backfill, conventional longwall mining with the rejects backfill, fully mechanized longwall coal mining with rejects backfill, high water material backfill and others. The solid rejects backfill of mine roadway heading is suitale for minor output and important protected buildings places. The longwall fully mech- anized mining with solid rejects and paste backfill is saitable for the meohanized coal mining and conventional mining under the protected buildings places. The high water backfill materia is suitable for the mine with shortage of backfill material and a single seam. The coal pro- duction, backfill value, coal recovery rate, cost per ton of coal, backfill rate, convergence value, subsidence value, subsidence reduction rate, deformation value and protected area were provide as the evaluation indexes of the backfill mining effect. Finally, a fruther study should be conducted on high efficient backfill mining, backfill space sealing and others.%基于煤矿可持续发展与环境保护的要求,阐述了煤矿充填开采的必要性,通过收集分析我国20个典型充填开采应用实例,系统论述了巷道掘进抛矸充填、长壁普采矸石充填、长壁综采矸石充填、膏体充填和高水充填等技术特点,得出了巷道掘进矸石充填适用于配采和重要保护场合,长壁综采矸石和膏体充填适用于主采和普通保护场合,高水充填适用于缺少充填材料和单一煤层场合;提出了采煤量、充填量、采出率、吨煤成本、充满率、移近量、下沉量、减沉率、变形量和保护面积可作为充填开采效果的评价指

  19. Evaluation of Computational Method of High Reynolds Number Slurry Flow for Caverns Backfilling

    Energy Technology Data Exchange (ETDEWEB)

    Bettin, Giorgia [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-05-01

    The abandonment of salt caverns used for brining or product storage poses a significant environmental and economic risk. Risk mitigation can in part be address ed by the process of backfilling which can improve the cavern geomechanical stability and reduce the risk o f fluid loss to the environment. This study evaluate s a currently available computational tool , Barracuda, to simulate such process es as slurry flow at high Reynolds number with high particle loading . Using Barracuda software, a parametric sequence of simu lations evaluated slurry flow at Re ynolds number up to 15000 and loading up to 25%. Li mitations come into the long time required to run these simulation s due in particular to the mesh size requirement at the jet nozzle. This study has found that slurry - jet width and centerline velocities are functions of Re ynold s number and volume fractio n The solid phase was found to spread less than the water - phase with a spreading rate smaller than 1 , dependent on the volume fraction. Particle size distribution does seem to have a large influence on the jet flow development. This study constitutes a first step to understand the behavior of highly loaded slurries and their ultimate application to cavern backfilling.

  20. The Buffer and Backfill Handbook. Part 3: Models for calculation of processes and behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Roland [Geodevelopment AB, Lund (Sweden)

    2003-01-15

    The present document collects conceptual and mathematical models that have been proposed for describing the performance of buffers and backfills and processes in them that are related to their function under repository conditions. As in the preceding parts the following types of sealing components are defined. By definition, the buffer shall be so composed that radionuclide transport in the clay-based barriers takes place by diffusion and not by water flow, which makes it important to predict the extent and rate of diffusive transport of such elements through the buffer. It depends strongly on the density and homogeneity of the buffer, which in turn depend on the maturation rate and the ultimate degree of homogeneity of the buffer. They are influenced by the temperature and temperature gradient that exist in the initial phase of water saturation, in which the hydraulic interaction with the near field rock is also important. Design of suitable buffer and backfills hence requires that their performance can be quantified, which requires that the various processes can be modeled conceptually and expressed in mathematical form. Based on the present knowledge this can only be made for some of the involved mechanisms and for coupled processes there is still a very limited number of mathematically expressed computational codes. The models referred to here are conceptual in the first place, defining the respective processes and material property parameters. The quick development of computational tools, numerical as well as analytical, makes it irrelevant to give detailed descriptions of them, while the various assumptions on which they are based - especially the conceptual models - have been considered in some detail. The models of practical use are only described in general terms and examples at the end of the respective chapter illustrate how they can be utilized. A very important fact is that transport and rheological processes in a repository are hardly ever of simple

  1. Assessment of arsenic immobilization in synthetically prepared cemented paste backfill specimens.

    Science.gov (United States)

    Coussy, Samuel; Benzaazoua, Mostafa; Blanc, Denise; Moszkowicz, Pierre; Bussière, Bruno

    2012-01-01

    Mine tailings coming from the exploitation of sulphide and/or gold deposits can contain significant amounts of arsenic (As), highly soluble in conditions of weathering. Open mine voids backfilling techniques are now widely practiced by modern mining companies to manage the tailings. The most common one is called cemented paste backfill (CPB), and consists of tailings mixed with low amounts of hydraulic binders (3-5%) and a high proportion of water (typically 25%). The CPB is transported through a pipe network, to be placed in the mine openings. CPB provides storage benefits and underground support during mining operations. Moreover, this technique could also enhance contaminant stabilization, by fixing the contaminants in the binder matrix. CPB composites artificially spiked with As were synthesized in laboratory, using two types of hydraulic binders: a Portland cement, and a mix of fly ash and Portland cement. After curing duration of 66 days, the CPB samples were subjected to several leaching tests in various experimental conditions in order to better understand and then predict the As geochemical behaviour within CPBs. The assessment of the As release indicates that this element is better stabilized in Portland cement-based matrices rather than fly ash-based matrices. The As mobility differs in these two matrices, mainly because of the different As-bearing minerals formed during hydration processes. However, the total As depletion does not exceed 5% at the end of the most aggressive leaching test, indicating that As is well immobilized in the two types of CPB. PMID:22054566

  2. Initial field testing definition of subsurface sealing and backfilling tests in unsaturated tuff

    International Nuclear Information System (INIS)

    This report contains an initial definition of the field tests proposed for the Yucca Mountain Project repository sealing program. The tests are intended to resolve various performance and emplacement concerns. Examples of concerns to be addressed include achieving selected hydrologic and structural requirements for seals, removing portions of the shaft liner, excavating keyways, emplacing cementitious and earthen seals, reducing the impact of fines on the hydraulic conductivity of fractures, efficient grouting of fracture zones, sealing of exploratory boreholes, and controlling the flow of water by using engineered designs. Ten discrete tests are proposed to address these and other concerns. These tests are divided into two groups: Seal component tests and performance confirmation tests. The seal component tests are thorough small-scale in situ tests, the intermediate-scale borehole seal tests, the fracture grouting tests, the surface backfill tests, and the grouted rock mass tests. The seal system tests are the seepage control tests, the backfill tests, the bulkhead test in the Calico Hills unit, the large-scale shaft seal and shaft fill tests, and the remote borehole sealing tests. The tests are proposed to be performed in six discrete areas, including welded and non-welded environments, primarily located outside the potential repository area. The final selection of sealing tests will depend on the nature of the geologic and hydrologic conditions encountered during the development of the Exploratory Studies Facility and detailed numerical analyses. Tests are likely to be performed both before and after License Application

  3. Coupled thermal-hydro analysis of unsaturated buffer and backfill in a high-level waste repository

    International Nuclear Information System (INIS)

    Highlights: • The sensitivity analysis was carried out for the thermal-hydro model parameters. • The temperature distribution was sensitive to a change in the degree of saturation. • The degree of saturation distribution was sensitive to a variation in temperature. • A coupled TH behavior in the buffer and backfill of KRS repository was analyzed. - Abstract: The buffer and backfill are the major components of an engineered barrier system (EBS) for a high level waste (HLW) repository. Reliable EBS performance assessment requires the delicate numerical modeling of the buffer and backfill. This study carried out the sensitivity analysis of thermal-hydro (TH) model parameters, and based on its results, the coupled TH analysis of an unsaturated buffer and backfill in an HLW repository. The temperature distribution was sensitive to a change in the degree of saturation and thus the thermal conductivity, and the degree of saturation distribution was sensitive to a variation in temperature and thus water viscosity. The decay heat of HLW from a canister dissipated out through the buffer and backfill into the surrounding rock. The temperature was higher closer to the canister and was lower farther from the canister. The temperature in the backfill was overall lower than that in the buffer, but both temperatures were approached slowly over a long time. The peak temperature was located at the center of the interface line between the canister and buffer, and was 107 °C at the elapsed time of 0.47 year. Re-saturation occurred in the order of the backfill and then a buffer as groundwater was intruded from the surrounding rock. The wetting of the backfill was initiated from the wall of the tunnel and the upper wall of deposition hole, and it then proceeded toward the inside. The buffer was wetted from the wall of the deposition toward the canister. The latest re-saturation location was a bit above from the center axis of the canister, at which the re-saturation period of

  4. Mining pressure monitoring and analysis in fully mechanized backfilling coal mining face-A case study in Zhai Zhen Coal Mine

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qiang; ZHANG Ji-xiong; KANG Tao; SUN Qiang; LI Wei-kang

    2015-01-01

    Fully mechanized solid backfill mining (FMSBM) technology adopts dense backfill body to support the roof. Based on the distinguishing characteristics and mine pressure control principle in this technology, the basic principles and methods for mining pressure monitoring were analyzed and established. And the characteristics of overburden strata movement were analyzed by monitoring the support resistance of hydraulic support, the dynamic subsidence of immediate roof, the stress of backfill body, the front abutment pressure, and the mass ratio of cut coal to backfilled materials. On-site strata behavior measurements of 7403W solid backfilling working face in Zhai Zhen Coal Mine show that the backfill body can effectively support the overburden load, obviously control the overburden strata movement, and weaken the strata behaviors distinctly. Specific performances are as follows. The support resistance decreases obviously; the dynamic subsidence of immediate roof keeps consistent to the variation of backfill body stress, and tends to be stable after the face retreating to 120-150 m away from the cut. The peak value of front abutment pressure arises at 5-12 m before the operating face, and mass ratio is greater than the designed value of 1.15, which effectively ensures the control of strata movement. The research results are bases for intensively studying basic theories of solid backfill mining strata behaviors and its control, and provide theoretical guidance for engineering design in FMSBM.

  5. 30 CFR 717.14 - Backfilling and grading of road cuts, mine entry area cuts, and other surface work areas.

    Science.gov (United States)

    2010-07-01

    ..., ensure stability, and control erosion on final graded slopes, cut-and-fill terraces may be allowed if the... authority to prevent excessive erosion and to provide long/term stability. (3) The slope of the terrace... original contour. The permittee shall transport, backfill and compact fill material to assure stability...

  6. Fat metaplasia and backfill are key intermediaries in the development of sacroiliac joint ankylosis in patients with ankylosing spondylitis

    DEFF Research Database (Denmark)

    Maksymowych, Walter P; Wichuk, Stephanie; Chiowchanwisawakit, Praveena;

    2014-01-01

    OBJECTIVE: Fat metaplasia in bone marrow on T1-weighted magnetic resonance imaging (MRI) scans may develop after resolution of inflammation in patients with ankylosing spondylitis (AS) and may predict new bone formation in the spine. Similar tissue, termed backfill, may also fill areas of excavated...

  7. Residual porosity and permeability of compacting salt grit backfill. REPOPERM - phase 1

    International Nuclear Information System (INIS)

    The direct disposal of spent nuclear fuel elements in BSK3 canisters in deep vertical boreholes is supposed to allow a safe long-term confinement in the host rock by backfilling of the holes using similar salt grit. The assessment of a long-term safe isolation of finally disposed radioactive wastes is usually performed using simulation models. Due to the lack of experimental data on the residual porosities of during the compacting process this issue is of increasing importance for the verification of a complete confinement within the safety concept of direct waste repositories. The Contribution covers the following topics: Determination of the state of knowledge on mechanical and hydraulic properties; development of a THMC model for a generic repository borehole; laboratory experiments with accompanying modeling calculations and planning of an in-situ experiment for complete confinement. The described investigations are the preliminary work for the subsequent project phase.

  8. Calculation method of first collapse span with superhigh water material backfill mining

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-ya; DENG Ka-zhong

    2012-01-01

    It is critical for the material to be of active supporting capacity before initial collapse of main roof with superhigh water material backfill mining,and the maximum bending moment should be first calculated in order to determine the initial collapse span.In the light of principal of virtual work,the simple expression of deflection,bending moment of elastic clamped plate were deduced under the condition of vertical uniform distributed load,horizontal pressure and supporting by elastic foundation,and then,the maximal bending moment expression was derived too.At the same time,the influence degree on square clamped plate by adding horizontal pressure and elastic foundation were analyzed.The results show that the effect of horizontal pressure on maximal bending moment can be ignored when the value of horizontal pressure is two orders of magnitude less than that of coefficient of elastic stiffness existing elastic foundation.

  9. Repair and restoration of paved surfaces. Phase 2: Backfilling of craters

    Science.gov (United States)

    Barber, V. C.

    1983-10-01

    The purpose of Phase II of REREPS (repair and restoration of paved surfaces) is to evaluate previously developed techniques and materials and to conduct necessary studies to determine the most beneficial backfill material. The study is to include new materials and innovative methodology to the greatest practicable extent. Compaction requirements are to be analyzed by comparison with existing requirements as modified by REREPS results to date. Specific compaction requirements include a quantification of compaction requirements versus depth below the load as well as subgrade compaction versus pavement strength and stiffness. Another specific requirement is to study the applicability of the sand grid support concept. In addition, other new methods and materials will be reviewed, developed, and/or introduced, as appropriate. This study constitutes partial completion of these objectives. An investigation research effort has been made to review the status of REREPS development to data.

  10. Backfilling with mixtures of bentonite/ballast materials or natural smectitic clay?

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, R. [Geodevelopment AB, (Sweden)

    1998-10-01

    Comparison of the performance of backfills of mixed MX-80 and crushed rock ballast, and a natural smectitic clay, represented by the German Friedland clay, shows that the latter performs better than mixtures with up to 30 % MX-80. Considering cost, Friedland clay prepared to yield air-dry powder grains is cheaper than mixtures of 30 % MX-80 and crushed ballast. Both technically and economically it appears that the Friedland clay is a competitive alternative to mixtures of 30 % MX-80 and crushed ballast. However, it remains to be demonstrated on a full scale that Friedland clay ground to a suitable grain size distribution can be acceptably compacted on site 14 refs, 32 figs, 6 tabs

  11. Engineered Barrier System - Long-term Stability of Buffer and Backfill. Synthesis and extended abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Apted, Mick; Arthur, Randy [Monitor Scientific LLC, Denver, CO (United States); Savage, Dave [Quintessa Ltd., Nottingham (GB)] (eds.)

    2005-09-15

    SKI is preparing to review the license applications being developed by the Swedish Nuclear Fuel and Waste Management Company (SKB) for an encapsulation plant and a deep repository for the geological disposal of spent nuclear fuel. As part of its preparation, SKI is conducting a series of technical workshops on key aspects of the Engineered Barrier System (EBS) of the repository. This workshop concerns the longterm stability of the buffer and the backfill. Previous workshops have addressed the overall concept for long-term integrity of the EBS, the manufacturing, testing and QA of the EBS and the performance confirmation for the EBS. The goal of this work is to achieve a comprehensive overview of all aspects of SKB's EBS work prior to the handling of forthcoming license applications. The reports from the EBS workshops will be used as one important basis in future review work. The workshops involve the gathering of a sufficient number of independent experts in different subjects of relevance to the particular aspect of EBS. A workshop starts with presentations and discussions among these experts. Following this, SKB presents recent results and responds to questions as part of an informal hearing. Finally, the independent experts and the SKI staff examine the SKB responses from different viewpoints. This report aims to summarise the issues discussed at the buffer and backfill workshop and to extract the essential viewpoints that have been expressed. The report is not a comprehensive record of the discussions and individual statements made by workshop participants should be regarded as opinions rather than proven facts. This reports includes apart from the workshop synthesis, questions to SKB identified prior or during the workshop, and extended abstracts for introductory presentations.

  12. Overview on backfill materials and permeable reactive barriers for nuclear waste disposal facilities

    International Nuclear Information System (INIS)

    A great deal of money and effort has been spent on environmental restoration during the past several decades. Significant progress has been made on improving air quality, cleaning up and preventing leaching from dumps and landfills, and improving surface water quality. However, significant challenges still exist in all of these areas. Among the more difficult and expensive environmental problems, and often the primary factor limiting closure of contaminated sites following surface restoration, is contamination of ground water. The most common technology used for remediating ground water is surface treatment where the water is pumped to the surface, treated and pumped back into the ground or released at a nearby river or lake. Although still useful for certain remediation scenarios, the limitations of pump-and-treat technologies have recently been recognized, along with the need for innovative solutions to ground-water contamination. Even with the current challenges we face there is a strong need to create geological repository systems for dispose of radioactive wastes containing long-lived radionuclides. The potential contamination of groundwater is a major factor in selection of a radioactive waste disposal site, design of the facility, future scenarios such as human intrusion into the repository and possible need for retrieving the radioactive material, and the use of backfills designed to keep the radionuclides immobile. One of the most promising technologies for remediation of contaminated sites and design of radioactive waste repositories is the use of permeable reactive barriers (PRBs). PRBs are constructed of reactive material(s) to intercept and remove the radionuclides from the water and decontaminate the plumes in situ. The concept of PRBs is relatively simple. The reactive material(s) is placed in the subsurface between the waste or contaminated area and the groundwater. Reactive materials used thus far in practice and research include zero valent iron

  13. Overview on backfill materials and permeable reactive barriers for nuclear waste disposal facilities.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert Charles; Hasan, Ahmed Ali Mohamed; Holt, Kathleen Caroline; Hasan, Mahmoud A. (Egyptian Atomic Energy Authority, Cairo, Egypt)

    2003-10-01

    A great deal of money and effort has been spent on environmental restoration during the past several decades. Significant progress has been made on improving air quality, cleaning up and preventing leaching from dumps and landfills, and improving surface water quality. However, significant challenges still exist in all of these areas. Among the more difficult and expensive environmental problems, and often the primary factor limiting closure of contaminated sites following surface restoration, is contamination of ground water. The most common technology used for remediating ground water is surface treatment where the water is pumped to the surface, treated and pumped back into the ground or released at a nearby river or lake. Although still useful for certain remediation scenarios, the limitations of pump-and-treat technologies have recently been recognized, along with the need for innovative solutions to ground-water contamination. Even with the current challenges we face there is a strong need to create geological repository systems for dispose of radioactive wastes containing long-lived radionuclides. The potential contamination of groundwater is a major factor in selection of a radioactive waste disposal site, design of the facility, future scenarios such as human intrusion into the repository and possible need for retrieving the radioactive material, and the use of backfills designed to keep the radionuclides immobile. One of the most promising technologies for remediation of contaminated sites and design of radioactive waste repositories is the use of permeable reactive barriers (PRBs). PRBs are constructed of reactive material(s) to intercept and remove the radionuclides from the water and decontaminate the plumes in situ. The concept of PRBs is relatively simple. The reactive material(s) is placed in the subsurface between the waste or contaminated area and the groundwater. Reactive materials used thus far in practice and research include zero valent iron

  14. FY:15 Transport Properties of Run-of-Mine Salt Backfill ? Unconsolidated to Consolidated.

    Energy Technology Data Exchange (ETDEWEB)

    Dewers, Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Leigh, Christi D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-28

    The nature of geologic disposal of nuclear waste in salt formations requires validated and verified two-phase flow models of transport of brine and gas through intact, damaged, and consolidating crushed salt. Such models exist in other realms of subsurface engineering for other lithologic classes (oil and gas, carbon sequestration etc. for clastics and carbonates) but have never been experimentally validated and parameterized for salt repository scenarios or performance assessment. Models for waste release scenarios in salt back-fill require phenomenological expressions for capillary pressure and relative permeability that are expected to change with degree of consolidation, and require experimental measurement to parameterize and validate. This report describes a preliminary assessment of the influence of consolidation (i.e. volume strain or porosity) on capillary entry pressure in two phase systems using mercury injection capillary pressure (MICP). This is to both determine the potential usefulness of the mercury intrusion porosimetry method, but also to enable a better experimental design for these tests. Salt consolidation experiments are performed using novel titanium oedometers, or uniaxial compression cells often used in soil mechanics, using sieved run-of-mine salt from the Waste Isolation Pilot Plant (WIPP) as starting material. Twelve tests are performed with various starting amounts of brine pore saturation, with axial stresses up to 6.2 MPa (~900 psi) and temperatures to 90°C. This corresponds to UFD Work Package 15SN08180211 milestone “FY:15 Transport Properties of Run-of-Mine Salt Backfill – Unconsolidated to Consolidated”. Samples exposed to uniaxial compression undergo time-dependent consolidation, or creep, to various degrees. Creep volume strain-time relations obey simple log-time behavior through the range of porosities (~50 to 2% as measured); creep strain rate increases with temperature and applied stress as expected. Mercury porosimetry

  15. Role of a buffer component within an engineered barrier waste package and a preliminary evaluation of bentonite as a backfill material

    International Nuclear Information System (INIS)

    This paper deals with the functions, properties, and compositions of backfill components to be used in the geologic disposal of high-level nuclear waste in basalt. A conceptual design for a repository located in basalt is being developed by the Basalt Waste Isolation Project (BWIP) in which these backfill components are part of the waste package and the repository sealing system (rooms, tunnels, and shafts). The first part of the paper concerns the role of a buffer component which is located between the primary and secondary physical barriers of the waste package (the canister and overpack). The second part of the paper deals with the chemical and physical properties of bentonite, which is a primary candidate for a backfill material both in the outer backfill barrier of the waste package and in the rooms, tunnels, and shafts above the waste package

  16. Experimental studies on the inventory of cement-derived colloids in the pore water of a cementitious backfill material

    Energy Technology Data Exchange (ETDEWEB)

    Wieland, E

    2001-06-01

    The potential role of near-field colloids for the colloid-facilitated migration of radionuclides has stimulated investigations concerning the generation and presence of colloids in the near-field of a repository for low- and intermediate level waste (L/ILW). The highly gas permeable mortar (Nagra designation: mortar M1) is currently favoured as backfill material for the engineered barrier of the planned Swiss L/ILW repository. The cementitious backfill is considered to be a chemical environment with some potential for colloid generation. In a series of batch-style laboratory experiments the physico-chemical processes controlling the inventory of colloids in cement pore water of the backfill were assessed for chemical conditions prevailing in the initial stage of the cement degradation. In these experiments, backfill mortar M1 or quartz, respectively, which may be used as aggregate material for the backfill, were immersed in artificial cement pore water (a NaOH/KOH rich cement fluid). Colloid concentrations in the cement pore water were recorded as a function of time for different experimental settings. The results indicate that a colloid-colloid interaction process (coagulation) controlled the colloid inventory. The mass concentration of dispersed colloids was found to be typically lower than 0.02 ppm in undisturbed batch systems. An upper-bound value was estimated to be 0.1 ppm taking into account uncertainties on the measurements. To assess the potential for colloid generation in a dynamic system, colloid concentrations were determined in the pore water of a column filled with backfill mortar. The chemical conditions established in the mortar column corresponded to conditions observed in the second stage of the cement degradation (a Ca(OH){sub 2{sup -}} controlled cement system). In this dynamic system, the upper-bound value for the colloid mass concentration was estimated to be 0.1 ppm. Implications for radionuclide mobility were deduced taking into account the

  17. Experimental studies on the inventory of cement-derived colloids in the pore water of a cementitious backfill material

    International Nuclear Information System (INIS)

    The potential role of near-field colloids for the colloid-facilitated migration of radionuclides has stimulated investigations concerning the generation and presence of colloids in the near-field of a repository for low- and intermediate level waste (L/ILW). The highly gas permeable mortar (Nagra designation: mortar M1) is currently favoured as backfill material for the engineered barrier of the planned Swiss L/ILW repository. The cementitious backfill is considered to be a chemical environment with some potential for colloid generation. In a series of batch-style laboratory experiments the physico-chemical processes controlling the inventory of colloids in cement pore water of the backfill were assessed for chemical conditions prevailing in the initial stage of the cement degradation. In these experiments, backfill mortar M1 or quartz, respectively, which may be used as aggregate material for the backfill, were immersed in artificial cement pore water (a NaOH/KOH rich cement fluid). Colloid concentrations in the cement pore water were recorded as a function of time for different experimental settings. The results indicate that a colloid-colloid interaction process (coagulation) controlled the colloid inventory. The mass concentration of dispersed colloids was found to be typically lower than 0.02 ppm in undisturbed batch systems. An upper-bound value was estimated to be 0.1 ppm taking into account uncertainties on the measurements. To assess the potential for colloid generation in a dynamic system, colloid concentrations were determined in the pore water of a column filled with backfill mortar. The chemical conditions established in the mortar column corresponded to conditions observed in the second stage of the cement degradation (a Ca(OH)2- controlled cement system). In this dynamic system, the upper-bound value for the colloid mass concentration was estimated to be 0.1 ppm. Implications for radionuclide mobility were deduced taking into account the experimental

  18. The solubility of nickel and its migration through the cementitious backfill of a geological disposal facility for nuclear waste.

    Science.gov (United States)

    Felipe-Sotelo, M; Hinchliff, J; Field, L P; Milodowski, A E; Holt, J D; Taylor, S E; Read, D

    2016-08-15

    This work describes the solubility of nickel under the alkaline conditions anticipated in the near field of a cementitious repository for intermediate level nuclear waste. The measured solubility of Ni in 95%-saturated Ca(OH)2 solution is similar to values obtained in water equilibrated with a bespoke cementitious backfill material, on the order of 5×10(-7)M. Solubility in 0.02M NaOH is one order of magnitude lower. For all solutions, the solubility limiting phase is Ni(OH)2; powder X-ray diffraction and scanning transmission electron microscopy indicate that differences in crystallinity are the likely cause of the lower solubility observed in NaOH. The presence of cellulose degradation products causes an increase in the solubility of Ni by approximately one order of magnitude. The organic compounds significantly increase the rate of Ni transport under advective conditions and show measurable diffusive transport through intact monoliths of the cementitious backfill material.

  19. Crushed aggregate-betonite mixtures as backfill material for the Finnish repositories of low- and intermediate-level radioactive wastes

    International Nuclear Information System (INIS)

    Backfill materials consisting of three components: crushed rock aggregate, finely ground rock aggregate and bentonite (3 to 2 per cent of weight) were studied. The production and installation procedures of the material were evaluated. Laboratory tests were made to determine the hydraulic conductivity and swelling potential of the materials. Chemical tests were made on the different materials and groundwaters. Mineralogical changes of the clay fraction were estimated. (author)

  20. Ferricyanide-backfilled cylindrical carbon fiber microelectrodes for in vivo analysis with high stability and low polarized potential.

    Science.gov (United States)

    Zhong, Peipei; Yu, Ping; Wang, Kai; Hao, Jie; Fei, Junjie; Mao, Lanqun

    2015-11-01

    The development of stable and reproducible methods for in vivo electrochemical monitoring of neurochemicals is of great physiological importance. In this study, we demonstrate ferricyanide-filled cylindrical carbon fiber microelectrodes (CFEs) of high stability and low polarized potential for in vivo electrochemical analysis. We first studied the voltammetric behavior of cylindrical CFEs by using a model system consisting of two separated cells each containing potassium ferricyanide (K3Fe(CN)6) or potassium ferrocyanide (K4Fe(CN)6). We observed that E1/2 values of the system were dependent on the ratio of the lengths of the cylindrical CFEs and of the concentrations of the redox species on both poles. Based on this property, we prepared the ferricyanide-backfilled cylindrical CFEs, and found that this kind of electrode exhibits a more stable current response and a lower polarized potential than the CFEs backfilled with KCl or Ru(NH3)6Cl3. Animal experiments with the ferricyanide-backfilled cylindrical CFEs demonstrate that this kind of electrode could be used for in vivo monitoring of neurochemical release with a high stability under some physiological conditions. PMID:26378690

  1. A Numerical Model for Natural Backfill of Pipeline Trenches Subjected to Unidirectional/Oscillatory Flows

    Institute of Scientific and Technical Information of China (English)

    LIANG Dong-fang; CHENG Liang; Kervin YEOW

    2005-01-01

    A numerical model for the self-burial of a pipeline trench is developed. Morphological evolutions of a pipeline trench under steady-current or oscillatory-flow conditions are simulated with/without a pipeline inside the trench. The oscillatory flow in this study represents the action of waves. The two-dimensional Reynolds-averaged continuity and Navier-Stokes equations with the standard k-ε turbulence closure, as well as the sediment transport equations, are solved with the finite difference method in a curvilinear coordinate system. Both bed and suspended loads of sediment transport are included in the morphological model. Because of the lack of experimental data on the backfilling of pipeline trenches, the numerical model is firetly verified against three closely-relevant experiments available in literature. A detailed measurement of the channel migration phenomenon under steady currents is employed for the assessment of the integral performance of the model. The two experimental results from U-tube tests are used to validate the model's ability in predicting oscillatory flows. Different time-marching schemes are employed for the morphological computation under unidirectional and oscillatory conditions. It is found that vortex motions within the trench play an important role in the trench development.

  2. Buffer and backfill process report for the safety assessment SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Sellin, Patrik (comp.)

    2006-09-15

    This document compiles information on processes in the buffer and deposition tunnel backfill relevant for long-term safety of a KBS-repository. It supports the safety assessment SR-Can, which is a preparatory step for a safety assessment that will support the licence application for a final repository in Sweden. The purpose of the process reports is to document the scientific knowledge of the processes to a level required for an adequate treatment of the processes in the safety assessment. The documentation is not exhaustive from a scientific point of view, since such a treatment is neither necessary for the purposes of the safety assessment nor possible within the scope of an assessment. However, it must be sufficiently detailed to motivate, by arguments founded on scientific understanding, the treatment of each process in the safety assessment. The purpose is further to determine how to handle each process in the safety assessment at an appropriate degree of detail, and to demonstrate how uncertainties are taken care of, given the suggested handling.

  3. Composite backfill materials for radioactive waste isolation by deep burial in salt

    International Nuclear Information System (INIS)

    Bentonite and hectorite were found to sorb Pu(IV) and Am(III) from concentrated brines with distribution coefficients K/sub d/ > 3000 ml/g. The permeability of bentonite to brine was less than 1 microdarcy at a confining pressure of 18 MPa, the expected lithostatic pressure at the 800 m level in a salt repository. Getters for sorption of TcO4- (K/sub d/ approx. 300 ml/g), I- (K/sub d/ greater than or equal to 30 ml/g), Cs (K/sub d/ greater than or equal to 30 ml/g) and Sr (K/sub d/ greater than or equal to approx. 100 ml/g) from brines were identified. Their sorption properties are presented. Thermal conductivity results (>0.5 W/mK) and evidence for bentonite stability in brines at hydrothermal conditions are also given. It is shown by calculated estimates that a 3-ft-thick mixture of bentonite with other getter materials could retain Pu, Am, and TcO4- for >104 years and I- for > 103 years. Another tailored mixture could retain Cs for approx. 600 years, Sr for approx. 700 years, TcO4 for approx. 4000 years and I- for approx. 400 years. The backfill can offer a significant contribution to the isolation capability of a waste package system

  4. Coupled effect of cement hydration and temperature on hydraulic behavior of cemented tailings backfill

    Institute of Scientific and Technical Information of China (English)

    WU Di; CAI Si-jing

    2015-01-01

    Cemented tailings backfill (CTB) is made by mixing cement, tailings and water together, thus cement hydration and water seepage flow are the two crucial factors affecting the quality of CTB. Cement hydration process can release significant amount of heat to raise the temperature of CTB and in turn increase the rate of cement hydration. Meanwhile, the progress of cement hydration consumes water and produces hydration products to change the pore structures within CTB, which further influences the hydraulic behavior of CTB. In order to understand the hydraulic behavior of CTB, a numerical model was developed by coupling the hydraulic, thermal and hydration equations. This model was then implemented into COMSOL Multiphysics to simulate the evolutions of temperature and water seepage flow within CTB versus curing time. The predicted outcomes were compared with correspondent experimental results, proving the validity and availability of this model. By taking advantage of the validated model, effects of various initial CTB and curing temperatures, cement content, and CTB's geometric shapes on the hydraulic behavior of CTB were demonstrated numerically. The presented conclusions can contribute to preparing more environmentally friendly CTB structures.

  5. The Buffer and Backfill Handbook. Part 1: Definitions, basic relationships and laboratory methods

    International Nuclear Information System (INIS)

    Part 1 of this Handbook is focused on description of fundamental issues of soil physical and chemical arts and on soil mechanical definitions and relationships. Part 2 comprises a material data basis including also preparation and field testing methods. Part 3 provides a collection of physical and mathematical models and examples of how they can and should be applied. The present document, which has been prepared by Geodevelopment AB in co-operation with Scandia Consult AB and Clay Technology AB, Sweden, and with TVO, Finland, makes up Part 1. Most of the data and information emanate from the work that Geodevelopment AB and Clay Technology AB have performed for SKB but a number of results from experiments made in and for other organizations have been included as well. A significant number of experimental procedures and ways of characterizing buffers and backfills are included. The experience from the comprehensive international Stripa Project, concerning both systematic material investigations in the laboratory and the full-scale field experiments, has contributed significantly to this report. However, similar and additional information gained from later work in SKB's Aespoe Hard Rock Laboratory and from NAGRA and also from other waste-isolation projects have helped to make this document of assumed international interest

  6. The Buffer and Backfill Handbook. Part 1: Definitions, basic relationships and laboratory methods

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Roland [Geodevelopment AB, Lund (Sweden)

    2002-04-01

    Part 1 of this Handbook is focused on description of fundamental issues of soil physical and chemical arts and on soil mechanical definitions and relationships. Part 2 comprises a material data basis including also preparation and field testing methods. Part 3 provides a collection of physical and mathematical models and examples of how they can and should be applied. The present document, which has been prepared by Geodevelopment AB in co-operation with Scandia Consult AB and Clay Technology AB, Sweden, and with TVO, Finland, makes up Part 1. Most of the data and information emanate from the work that Geodevelopment AB and Clay Technology AB have performed for SKB but a number of results from experiments made in and for other organizations have been included as well. A significant number of experimental procedures and ways of characterizing buffers and backfills are included. The experience from the comprehensive international Stripa Project, concerning both systematic material investigations in the laboratory and the full-scale field experiments, has contributed significantly to this report. However, similar and additional information gained from later work in SKB's Aespoe Hard Rock Laboratory and from NAGRA and also from other waste-isolation projects have helped to make this document of assumed international interest.

  7. A numerical study of macro-mesoscopic mechanical properties of gangue backfill under biaxial compression

    Institute of Scientific and Technical Information of China (English)

    Huang Zhimin; Ma Zhanguo; Zhang Lei; Gong Peng; Zhang Yankun; Liu Fei

    2016-01-01

    Based on the Particle Flow Code (PFC2D) program, we set up gangue backfill models with different gangue contents and bond strength, and studied the stress–strain behaviours, the pattern of shear band and force chains, motion and fragmentation of particles under biaxial compression. The results show that when the bond strength or contents of gangue are high, the peak strength is high and the phenomena of post-peak softening and fluctuation are obvious. When gangue contents are low, the shape of the shear band is sym-metrical and most strong force chains transfer in soil particles. With an increase in gangue content, the shape of the shear band becomes irregular and the majority of strong force chains turn to transfer in gangue particles gradually, most of which distribute along the axial direction. When the gangue content is higher than 50%, the interconnectivity of strong force chains decreases gradually;at the same time, the strong force chains become tilted and the stability of the system tends to decrease. With an increase in external loading, the coordination numbers of the system increase at first and then decrease and the main pattern of force chains changes into columnar from annular. However, after the forming of the advanta-geous shear band, the force chains external to the shear band maintain their columnar shape while the inner ones bend obviously. As a result, annular force chains form.

  8. Utilization of water-reducing admixtures in cemented paste backfill of sulphide-rich mill tailings.

    Science.gov (United States)

    Ercikdi, Bayram; Cihangir, Ferdi; Kesimal, Ayhan; Deveci, Haci; Alp, Ibrahim

    2010-07-15

    This study presents the effect of three different water-reducing admixtures (WRAs) on the rheological and mechanical properties of cemented paste backfill (CPB) samples. A 28-day strength of > or = 0.7 MPa and the maintenance of the stability (i.e. > or = 0.7 MPa) over 360 days of curing were desired as the design criteria. Ordinary Portland cement (OPC) and Portland composite cement (PCC) were used as binders at 5 wt.% dose. WRAs were initially tested to determine the dosage of a WRA for a required consistency of 7'' for CPB mixtures. A total of 192 CPB samples were then prepared using WRAs. The utilization of WRAs enhanced the flow characteristics of the CPB mixture and allowed to achieve the same consistency at a lower water-to-cement ratio. For OPC, the addition of WRAs appeared to improve the both short- and long-term performance of CPB samples. However, only polycarboxylate-based superplasticiser produced the desired 28-day strength of > or = 0.7 MPa when PCC was used as the binder. These findings suggest that WRAs can be suitably exploited for CPB of sulphide-rich tailings to improve the strength and stability in short and long terms allowing to reduce binder costs in a CPB plant. PMID:20382473

  9. THM modelling of buffer, backfill and other system components. Critical processes and scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias; Kristensson, Ola; Boergesson, Lennart; Dueck, Ann (Clay Technology AB, Lund (Sweden)); Hernelind, Jan (5T-Engineering AB, Vaesteraas (Sweden))

    2010-03-15

    A number of critical thermo-hydro-mechanical processes and scenarios for the buffer, tunnel backfill and other filling components in the repository have been identified. These processes and scenarios representing different aspects of the repository evolution have been pinpointed and modelled. In total, 22 cases have been modelled. Most cases have been analysed with finite element (FE) calculations, using primarily the two codes Abaqus and Code-Bright. For some cases analytical methods have been used either to supplement the FE calculations or due to that the scenario has a character that makes it unsuitable or very difficult to use the FE method. Material models and element models and choice of parameters as well as presumptions have been stated for all modelling cases. In addition, the results have been analysed and conclusions drawn for each case. The uncertainties have also been analysed. Besides the information given for all cases studied, the codes and material models have been described in a separate so called data report

  10. SR-Site Data report. THM modelling of buffer, backfill and other system components

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias; Boergesson, Lennart; Kristensson, Ola (Clay Technology AB, Lund (Sweden))

    2010-03-15

    This report is a supplement to the SR-Site data report. Based on the issues raised in the Process reports concerning THM processes in buffer, backfill and other system components, 22 modelling tasks have been identified, representing different aspects of the repository evolution. The purpose of this data report is to provide parameter values for the materials included in these tasks. Two codes, Code{_}Bright and Abaqus, have been employed for the tasks. The data qualification has focused on the bentonite material for buffer, backfill and the seals for tunnel plugs and bore-holes. All these system components have been treated as if they were based on MX-80 bentonite. The sources of information and documentation of the data qualification for the parameters for MX-80 have been listed. A substantial part of the refinement, especially concerning parameters used for Code{_}Bright, is presented in the report. The data qualification has been performed through a motivated and transparent chain; from measurements, via evaluations, to parameter determinations. The measured data was selected to be as recent, traceable and independent as possible. The data sets from this process are thus regarded to be qualified. The conditions for which the data is supplied, the conceptual uncertainties, the spatial and temporal variability and correlations are briefly presented and discussed. A more detailed discussion concerning the data uncertainty due to precision, bias and representativity is presented for measurements of swelling pressure, hydraulic conductivity, shear strength, retention properties and thermal conductivity. The results from the data qualification are presented as a detailed evaluation of measured data. In order to strengthen the relevance of the parameter values and to confirm previously used relations, either newer or independent measurements have been taken into account in the parameter value evaluation. Previously used relations for swelling pressure, hydraulic

  11. Swelling behavior of GMZ01 buffer/backfill material under flexible boundary condition

    International Nuclear Information System (INIS)

    In the high-level radioactive waste geological repository, the swelling properties of buffer/backfill material play an important role for insuring the long-term stability and safety of the repository. Traditionally, soil swelling behavior has been thoroughly examined under two extreme boundary conditions that included constant volume and constant stress. However, there exist infinite possible intermediate conditions that are neither constant volume nor constant stress and are termed flexible boundary conditions. In literature, the information on soil swelling behavior under flexible boundary condition is limited. In this investigation, a special flexible load ring-type device was developed to perform swelling tests on Gaomiaozi (GMZ01) bentonite under flexible boundary conditions, where the applied stress increases with increasing volume at a specified function. The initial dry density of the soil sample is 1.7 g/cm3, the applied initial axial stress is 0.2 MPa. The results indicate that the developed load ring-type device is effective to characterize the swelling behavior of soil sample under flexible boundary conditions; both the swelling strain and swelling pressure increase with increasing flooding time and then gradually reach stabilization, and the void ratio of the sample increases linearly with increasing swelling pressure; with increasing stiffness of the load ring, the finial swelling stain decreases while the final swelling pressure increases. For the tested soil sample, as the stiffness of the load ring increases from 278.5 N/mm to 2152 N/mm, the final equilibrium swelling strain decreases from 15.88% to 6.84%, while the final equilibrium swelling pressure increases from 0.59 MPa to 1.50 MPa. The experimental results highlights that choosing an appropriate swelling testing technique to simulate the field conditions is essential for design and evaluation of soil swelling potential. (authors)

  12. Diffusion coefficient test of {sup 237}Np in bentonite backfill materials

    Energy Technology Data Exchange (ETDEWEB)

    Cui Anxi; Fan Zhiwen; Zhang Jinsheng; Gu Cunli [China Inst. for Radiation Protection, Shanxi (China); Mukai, M.; Maeda, T.; Matsumoto, J.; Tanaka, T.; Ogawa, H. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-03-01

    This paper describes the work on diffusion coefficient test of Np in bentonite backfill materials. Due to its very low permeability, diffusion is the dominant migration mechanics in bentonite. The bentonite comes from Inner Mongolia of China. {sup 237}Np was used as tracer. The special apparatus for diffusion test was setup, the diffusion coefficient of Np in pure bentonite and sand-bentonite mixture were tested. The tracer was introduced between two bentonite columns. After a specific contacting period, the bentonite columns were taken out and cut to very thin slices. The radioactivity in bentonite slices was analyzed to give the nuclide concentration versus distance curves. The diffusion coefficient could be estimated. The diffusion coefficient of pure bentonite at different density was tested. When the density of pure bentonite samples varied from 1.1, 1.3, 1.5 to 1.7 g/ml, their diffusion coefficient were 1.36 x 10{sup -13} m{sup 2}/s 1.16 x 10{sup -13}m{sup 2}/s, 1.07 x 10{sup -13} m{sup 2}/s and 8.26 x 10{sup -14} m{sup 2}/s respectively. The diffusion coefficient of Np in sand-bentonite mixture sample was 4.13 x 10{sup -13} m{sup 2}/s. To estimate the distribution coefficient (K{sub d}) value of Np in mixture sample by diffusion method, the diffusion coefficient of Br was measured./ The concluded K{sub d} value was 77ml/g for the sand-bentonite mixture. The K{sub d} value obtained by batch test methods was 30ml/g. The reason is related with the error of Br diffusion coefficient and solid-liquid ratio. (author)

  13. Characterization of a backfill candidate material, IBECO-RWC-BF Baclo Project - Phase 3 Laboratory tests

    Energy Technology Data Exchange (ETDEWEB)

    Johannesson, Lars-Erik; Sanden, Torbjoern; Dueck, Ann; Ohlsson, Lars (Clay Technology AB, Lund (Sweden))

    2010-01-15

    A backfill candidate material, IBECO-RWC-BF, which origin from Milos, Greece, has been investigated. The material was delivered both as granules and as pellets. The investigation described in this report aimed to characterize the material and evaluate if it can be used in a future repository. The following investigations have been done and are presented in this report: 1. Standard laboratory tests. Water content, liquid limit and swelling potential are examples on standard tests that have been performed. 2. Block manufacturing. The block compaction properties of the material have been determined. A first test was performed in laboratory but also tests in large scale have been performed. After finishing the test phase, 60 tons of blocks were manufactured at Hoeganaes Bjuf AB. The blocks will be used in large scale laboratory tests at Aespoe HRL. 3. Mechanical parameters. The compressibility of the material was investigated with oedometer tests (four tests) where the load was applied in steps after saturation. The evaluated oedometer modulus varied between 34.50 MPa. Tests were made to evaluate the elastic parameters of the material (E, nu). Altogether three tests were made on specimens with dry densities of about 1,710 kg/m3. The evaluated E-modulus and Poisson's ratio varied between 231-263 MPa and 0.16-0.19 respectively. The strength of the material, both the compressive strength and the tensile strength were measured on specimens compacted to different dry densities. The test results yielded a relation between density and the two types of strength. Furthermore, tests have been made in order to determine the compressibility of the unsaturated filling of pellets. Two tests were made where the pellets were loosely filled in a Proctor cylinder and then compressed at a constant rate of strain during continuously measurement of the applied load. 4. Swelling pressure and hydraulic conductivity. There is, as expected, a very clear influence of the dry density on the

  14. Borehole Heat Exchanger Systems: Hydraulic Conductivity and Frost-Resistance of Backfill Materials

    Science.gov (United States)

    Anbergen, Hauke; Sass, Ingo

    2016-04-01

    Ground source heat pump (GSHP) systems are economic solutions for both, domestic heating energy supply, as well as underground thermal energy storage (UTES). Over the past decades the technology developed to complex, advanced and highly efficient systems. For an efficient operation of the most common type of UTES, borehole heat exchanger (BHE) systems, it is necessary to design the system for a wide range of carrier fluid temperatures. During heat extraction, a cooled carrier fluid is heated up by geothermal energy. This collected thermal energy is energetically used by the heat pump. Thereby the carrier fluid temperature must have a lower temperature than the surrounding underground in order to collect heat energy. The steeper the thermal gradient, the more energy is transferred to the carrier fluid. The heat injection case works vice versa. For fast and sufficient heat extraction, even over long periods of heating (winter), it might become necessary to run the BHE with fluid temperatures below 0°C. As the heat pump runs periodically, a cyclic freezing of the pore water and corresponding ice-lens growth in the nearfield of the BHE pipes becomes possible. These so called freeze-thaw-cycles (FTC) are a critical state for the backfill material, as the sealing effect eventually decreases. From a hydrogeological point of view the vertical sealing of the BHE needs to be secured at any time (e.g. VDI 4640-2, Draft 2015). The vertical hydraulic conductivity of the BHE is influenced not only by the permeability of the grouting material itself, but by the contact area between BHE pipes and grout. In order to assess the sealing capacity of grouting materials a laboratory testing procedure was developed that measures the vertical hydraulic conductivity of the system BHE pipe and grout. The key features of the procedure are: • assessment of the systeḿs hydraulic conductivity • assessment of the systeḿs hydraulic conductivity after simulation of freeze-thaw-cycle

  15. Research and application of schemes for constructing concrete pillars in large section finishing cut in backfill coal mining

    Institute of Scientific and Technical Information of China (English)

    Sun Qiang; Zhang Jixiong; Ju Feng; Li Linyue; Zhao Xu

    2015-01-01

    Based on the technology of controlling surrounding rock deformation by constructing concrete pillars in large section finishing cut in backfill coal mining, the characteristics of vertical stress on concrete pillars and main factors influencing pillar stability are analyzed. By building a Winkler elastic foundation mechanical model for the support system constituted of coal pillar, backfill body and concrete pillars, mechanical calculation on stability of concrete pillar is carried out to evaluate the pillar stability and safety. Seven numeral models in three schemes with different pillar sizes, inter-row distances and com-pression ratios at the stopes were analyzed through numerical simulation according to width reduction principle. The practice of finishing cut at III644 workface at Yangzhuang coal mine shows that:when the actual compression ratio is 86.5%, construction size inside the finishing cut is 2000 mm ? 2000 mm and the interval between concrete pillars is 2000 mm ? 2000 mm, the pillars can be stable with the maxi-mum movement of two sides of each pillar being only 83 mm and 54 mm, which achieves the expected effect.

  16. Calculation procedure in GOLIA-FAME for pressure adjustment as a function of the compressibility of backfill

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, L.F.M.

    1991-08-01

    In a repository for radioactive waste in a salt formation there are openings (boreholes and galleries) that are excavated or drilled in order to store the waste into the salt formation. After storage of the waste the remaining openings are backfilled with a salt mixture. The behaviour of the salt mixture is laid down in a relation between the volumetric compression rate of the mix and the compressive working on it. In this report a set of subroutines for the FE-code GOLIA-FAME is described which can be used to model the interaction between the salt and the backfill. An example is described and some numerical tests are presented. The subroutines can easily be implemented in the computer code GOLIA-FAME and can easily be adapted for other specific purposes than described in this report in which the deformation of the structure is related to a pressure change. In the future it will be investigated how the pressure adjustment can be implemented in the Runge-Kutta solution steps of GOLIA-FAME to improve the efficiency of the program. (author). 2 refs.; 9 figs.; 5 tabs.

  17. The solubility of nickel and its migration through the cementitious backfill of a geological disposal facility for nuclear waste.

    Science.gov (United States)

    Felipe-Sotelo, M; Hinchliff, J; Field, L P; Milodowski, A E; Holt, J D; Taylor, S E; Read, D

    2016-08-15

    This work describes the solubility of nickel under the alkaline conditions anticipated in the near field of a cementitious repository for intermediate level nuclear waste. The measured solubility of Ni in 95%-saturated Ca(OH)2 solution is similar to values obtained in water equilibrated with a bespoke cementitious backfill material, on the order of 5×10(-7)M. Solubility in 0.02M NaOH is one order of magnitude lower. For all solutions, the solubility limiting phase is Ni(OH)2; powder X-ray diffraction and scanning transmission electron microscopy indicate that differences in crystallinity are the likely cause of the lower solubility observed in NaOH. The presence of cellulose degradation products causes an increase in the solubility of Ni by approximately one order of magnitude. The organic compounds significantly increase the rate of Ni transport under advective conditions and show measurable diffusive transport through intact monoliths of the cementitious backfill material. PMID:27198634

  18. Sheetflow Effects and Canal Backfilling on Sediment Source and Transport in Everglades Freshwater Marshes: Analysis of Molecular Organic Biomarkers

    Science.gov (United States)

    Regier, P.; He, D.; Saunders, C.; Coronado-Molina, C.; Jara, B.; Jaffe, R.

    2014-12-01

    Historic freshwater sheetflow in the Florida Everglades distributed sediment to form a ridge-and-slough landscape. However, drainage along with reduction and obstruction of flow has resulted in degradation of this ridged topography. The DECOMP Physical Model is a landscape-scale project aiming to reestablish natural sheetflow to the central and southern Everglades by redesigning barriers to flow. To validate proof of concept that increased flow will rebuild ridge-slough microtopography, biomarker proxies were established for ridge and slough organic matter sources. In addition, partial and complete canal backfill options were assessed via sediment trap accumulation in each backfill treatment area. Flocculent matter (floc) and sediment samples were collected, solvent extracted, chromatographically separated, and analyzed on a GC/MS using internal standard for quantification. Four molecular organic biomarkers were evaluated: the aquatic proxy (Paq), highly-branched isoprenoids (C20 HBI), kaurenes and botyrococcenes. Paq, an aquatic proxy of mid to long-chain n-alkanes, was shown to clearly differentiate between ridge-derived and slough-derived organic matter with Paq values increasing along ridge-to-slough transects. Kaurenes indicated presence of ridge-derived organic matter while C20 HBI and botyrococcenes were indicative of periphyton-derived organic matter which is commonly more abundant in sloughs. Biomarker distributions during both low (present day) and high (managed) water flow through the DECOMP experimental parcel were determined and discussed comparatively.

  19. Hydraulic behaviour of bentonite based mixtures in engineered barriers: The Backfill and Plug Test at the Äspö HRL (Sweden)

    OpenAIRE

    Mata Mena, Clemente

    2003-01-01

    In 1996 the Backfill and Plug Test Project started at the Äspö Hard Rock Laboratory (Sweden) managed by SKB (the Swedish Radioactive Waste Agency). The Backfill and Plug Test Project makes up an important part of SKB's research in order to store nuclear waste in a deep geological repository in a safe manner. ENRESA (the Spanish Radioactive Waste Agency) collaborates in this project with the Swedish companies SKB and Clay Technology in characterising the hydro-mechanical behaviour of the backf...

  20. Characterisation of bentonites from Kutch, India and Milos, Greece - some candidate tunnel back-fill materials?

    International Nuclear Information System (INIS)

    During the past decades comprehensive investigations have been made on bentonite clays in order to find optimal components of the multi-barrier system of repositories for radioactive waste. The present study gives a mineralogical characterisation of some selected bentonites, in order to supply some of the necessary background data on the bentonites for evaluating their potential as tunnel back-fill materials. Two bentonites from the island of Milos, Greece (Milos BF 04 and BF 08), and two bentonites from Kutch, India (Kutch BF 04 and BF 08) were analysed for their grain size distribution, cation exchange properties and chemical composition. The mineralogical composition was determined by X-ray diffraction analysis and evaluated quantitatively by use of the Siroquant software. Both the bulk bentonite and the 63 μm. The bentonite is distinguished by a high content of dolomite and calcite, which make up almost 25% of the bulk sample. The major accessory minerals are K-feldspars and plagioclase, whereas the content of sulphur-bearing minerals is very low (0.06% total S). Smectite makes up around 60% of the bulk sample, which has a CEC value of 73 meq/100 g. The pool of interlayer cations has a composition Mg>Ca>>Na>>K. The X-ray diffraction characteristics and the high potassium content (1.03% K2O) of the Na>Mg>>K. The 2O) which indicates that also this smectite may be interstratified with a few percent illitic layers. Based on the charge distribution the smectite should be classified as montmorillonite but in this case Fe predominates over Mg in the octahedral sheet. The structural formula suggests that this smectite has the lowest total layer charge of the smectites examined. Kutch BF 04 contains essentially no particles >63 μm. The bentonite has a high content of titanium and iron-rich accessory minerals, such as anatase, magnetite, hematite and goethite. Other accessory minerals of significance are feldspars and quartz, whereas the content of sulphur

  1. Effect of desliming of sulphide-rich mill tailings on the long-term strength of cemented paste backfill.

    Science.gov (United States)

    Ercikdi, Bayram; Baki, Hakan; İzki, Muhammet

    2013-01-30

    This paper presents the effect of desliming on the short- and long-term strength, stability and rheological properties of cemented paste backfill (CPB) produced from two different mill tailings. A 28-day unconfined compressive strength (UCS) of ≥1.0 MPa and the maintenance of stability over 224 days of curing were selected as the design criteria for the evaluation of paste backfill performance. Desliming induced some changes in the physical, chemical, mineralogical and rheological properties of the tailings. CPB mixture of the deslimed tailings achieved the required consistency at a lower water to cement ratio. The short-term UCSs of CPB samples of the deslimed tailings were found to be 30-100% higher than those samples of the reference tailings at all the binder dosages and curing times. CPB samples of the deslimed tailings achieved the long-term stability at relatively low binder dosages (e.g. 5 wt% c.f. ≥6.1% for the reference tailings). It was also estimated that desliming could allow a 13.4-23.1% reduction in the binder consumption depending apparently on the inherent characteristics of the tailings. Over the curing period, generation of sulphate and acid by the oxidation of pyrite present in the tailings was also monitored to correlate with the strength losses observed in the long term. Scanning electron microscope (SEM) and Mercury Intrusion Porosimetry (MIP) analyses provided an insight into the microstructure of CPB and the formation of secondary mineral phases (i.e. gypsum) confirming the beneficial effect of desliming. These findings suggest that desliming can be suitably exploited for CPB of sulphide-rich mill tailings to improve the strength and stability particularly in the long term and to reduce binder consumption. PMID:23220652

  2. Backfilling-Free Strategy for Biopatterning on Intrinsically Dual-Functionalized Poly[2-Aminoethyl Methacrylate-co-Oligo(Ethylene Glycol) Methacrylate] Films.

    Science.gov (United States)

    Lee, Bong Soo; Lee, Juno; Han, Gyeongyeop; Ha, EunRae; Choi, Insung S; Lee, Jungkyu K

    2016-07-20

    We demonstrated protein and cellular patterning with a soft lithography technique using poly[2-aminoethyl methacrylate-co-oligo(ethylene glycol) methacrylate] films on gold surfaces without employing a backfilling process. The backfilling process plays an important role in successfully generating biopatterns; however, it has potential disadvantages in several interesting research and technical applications. To overcome the issue, a copolymer system having highly reactive functional groups and bioinert properties was introduced through a surface-initiated controlled radical polymerization with 2-aminoethyl methacrylate hydrochloride (AMA) and oligo(ethylene glycol) methacrylate (OEGMA). The prepared poly(AMA-co-OEGMA) film was fully characterized, and among the films having different thicknesses, the 35 nm-thick biotinylated, poly(AMA-co-OEGMA) film exhibited an optimum performance, such as the lowest nonspecific adsorption and the highest specific binding capability toward proteins. PMID:27252120

  3. Review of the sorption of radionuclides on the bedrock of Haestholmen and on construction and backfill materials of a final repository for reactor wastes

    International Nuclear Information System (INIS)

    Imatran Voima Oy (IVO) has plans to build a final repository for reactor wastes in the bedrock of the nuclear power plant site at Haestholmen, Loviisa. This report summarizes the sorption studies of radionuclides in Finnish bedrock performed at the Department of Radiochemistry, University of Helsinki. The values of mass distribution ratios, Kd, and surface distribution ratios, Ka; of carbon, calsium, Zirconium, niobium, cobalt, nickel, strontium, cesium, uranium, plutonium, americium, thorium, chlorine, iodine and technetium are surveyed. Special attention is paid to the sorption data for construction and backfill materials of rector waste repository and the bedrock of Haestholmen. Safety assessment of a repository includes calculations of migration of the waste element in construction materials and backfill in the nearfield and in bedrock. Retardation by sorption of waste nuclides compared to groundwater flow is described by using distribution ratios between solid materials and water. (orig.)

  4. Coupling mechanism of roof and supporting wall in gob-side entry retaining in fully-mechanized mining with gangue backfilling

    Institute of Scientific and Technical Information of China (English)

    Ma Zhanguo; Gong Peng; Fan Jinquan; Geng Minmin; Zhang Guowei

    2011-01-01

    We analyzed the deformation characteristics of overlying stratum in backfilling with fully-mechanized and retaining roadways along the gob area coal mining technology,and established a mechanical model for the roof key stratum of retaining roadways along gob under the conditions of backfilling and fullymechanized coal mining technology.Using Winkler elastic foundation theory,we analyzed a part of the key stratum under the action of elastic foundation coupling problem,and derived deflection analytical expressions.Combined with specific conditions,we obtained the deflection curves for the roof key stratum of retaining roadways along gob under the conditions of backfilling and fully-mechanized coal mining technology.On this basis,we adopted the Coulomb's earth pressure theory to solve the problem of lateral pressure of the gangue filling area on the supporting wall beside the roadway and to provide the theoretical basis for reasonable selection of the distance between gangue concrete wall and roof and further discussion on the supporting stability of roadway.

  5. Research and Application of Grouting Technique on Deep Foundation Pit of Backfill Soil%灌浆技术加固深基坑回填土的应用研究

    Institute of Scientific and Technical Information of China (English)

    张坤强; 刘福胜; 韩君格; 马飞

    2011-01-01

    针对深基坑回填土密实度低、塌陷问题进行加固研究,提出了纯压式灌浆加固技术在深基坑回填土加固中的应用。得出灌浆加固技术能很好地应用到深基坑回填土的加固中,既提高了回填土的密实度,亦增大了回填土的承载力及抗渗性能,对以后的相似工程推广应用具有理论及实践意义。%Due to the deep foundation pit backfill soil compaction degree is low, backfill soil collapse reinforced research problem, puts forward pure pressure type grouting technology in deep foun- dation pit backfill soil aplication. It's shows that the grouting reinforcement technique can be well applied on deep foundation pit of backfill soil reinforcement, not only improves the compactness of backfill soil, also increased the bearing capacity of backfill soil and anti - permeability. It has theoretical and practical significance for the following similar engineering application.

  6. Feasibility studies of air placed techniques as emplacement means of different backfilling materials in underground radioactive waste disposal

    International Nuclear Information System (INIS)

    Air placed techniques are likely to be used as emplacement means of different backfilling materials in underground waste repositories. A literature survey of the air placed techniques and equipments leads to the choice of the dry process taking into account the emplacement constraints (distance: 300 m, flow: 10 m3/h) and the large variety of materials to be placed. Tests performed in the case of cement-based materials (with and without addition of silica fumes), for different types of cement and as a function of the incidence of the jet, show that it is possible to put in place mortars of good quality. However heterogeneity in the material composition is found when the jet is stopped. This problem may be partly solved by a better automation of the process. Complementary tests, carried out with the preselected clay of Fourges Cahaignes, clearly demonstrate the ability of the air placed technique to put in place pure clay: a dry density of 1.50kg/m3 is reached in the case of coarse material and for a final water content of 30% (in weight). Feasibility tests performed on clay-sand mixtures are not conclusive due to an unappropriate granulometry distribution of the sand. 11 figs., 9 tabs

  7. Effects of Fine Gangue on Strength, Resistivity, and Microscopic Properties of Cemented Coal Gangue Backfill for Coal Mining

    Directory of Open Access Journals (Sweden)

    Tingye Qi

    2015-01-01

    Full Text Available The cemented coal gangue backfill (CGB in coal mining is normally made of gangue (particle size of 0–15 mm, fly ash, cement, and water. In this study, the effects of the weight content (ranging from 20% to 60% of fine gangue (0–5 mm on the microscopic characteristics, resistivity, and compressive strength of CGB were investigated at 3 d and 28 d curing times, respectively. The test results indicate that the strengths of the CGB, regardless of the curing time, increased with fine gangue content changing from 20% up to 40%. Further increase in fine gangue introduced a decrease in the strength. Another observation is that, at 3 days, a general increasing trend of CGB resistivity was noted with fine gangue content. At 28 days, the resistivity of CGB decreased with increase in the fine gangue content. Correlations between the resistivity and compression strength of CGB show a concave pattern, which attribute to the various micromechanism influenced on the resistivity and strength of CGB with different fine gangue content. It indicates that using resistivity to derive strength of CGB is not appropriate.

  8. Performance of concrete backfilling materials for shafts and tunnels in rock formations. Volume 1: concrete selection and properties

    International Nuclear Information System (INIS)

    Preplaced Aggregate Concrete (PAC) consists of graded coarse aggregate, immobilised by cementitious grout injected into the voids. PAC can be considered as a suitable backfill material for mined radioactive waste repositories. PAC is also reported to be amenable to mechanical/remote placement and have usefully improved properties when compared with conventionally placed concretes. In particular reduced shrinkage and heat cycle during cement hydration, higher densities and improved plant economics are claimed. This study attempts to establish the validity of these claims both from reported experience and by practical demonstration through experimentation. A literature study supported the claims made for the PAC system but all reported experiences recorded the use of organic admixtures (workability aids, retarders etc). Because of the lack of long term durability data on such admixtures, especially in a radiation environnement, it was decided to prepare a sample of PAC without organic admixtures. Considerable experimental difficulties were encountered in obtaining a satisfactory quality for test specimens. The necessary grout fluidity was only achieved by the inclusion of bentonite. The test data collected indicates that the PAC system employed did not improve mechanical properties compared with conventional concretes. This is attributed to the non-usage of organic admixtures to achieve the expected performance. Further research on low permeability concretes would require the use of organic admixtures. The effect of radiation on these materials, and their leaching rate needs to be quantified

  9. Effects of water inflow and early water uptake on buffer and backfill materials in a KBS-3V repository

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Bentonite is an excellent sealing material when it has reached full water saturation and swelling pressure. However, bentonite is not good for sealing inflowing water from fractures with potential to build high water pressure. It cannot stop inflow of water at the depth of a repository. The water inflow into the pellets filled slots in the deposition holes and the tunnels in a KBS-3V repository is expected to continue until these slots are water filled and the water flow stopped by an end plug. Then the water pressure gradient is transferred from the fracture/bentonite interface to the plug and the bentonite will have time to homogenize and seal. This scenario leads to a number of processes that can either be harmful to the bentonite or affect the water saturation and homogenization evolution. Last year a project (EVA) started in order to investigate the processes involved by this early water inflow. The project aims at developing a model for the processes piping, erosion, water filling of pellets filled slots, early water absorption and resulting water pressure increase against the plug. The project studies the effects of water inflow in deposition holes and deposition tunnels and the emergence of piping and erosion during installation and wetting of the buffer and backfill until all slots and the pellet fillings have been water filled and piping and erosion have ceased. The project includes laboratory tests of nine different processes and modeling. The laboratory program includes tests of the following processes: 1. Erosion; 2. Piping; 3. Water flow in pellet filled slots; 4. Sealing ability of bentonite; 5. Water absorption of the bentonite blocks; 6. Formation of water or gel pockets in a pellet filled slot; 7. Formation and outflow of bentonite gel; 8. Self-sealing of cracks by eroding water; 9. Buffer swelling before placement of backfill. The laboratory tests are ongoing and preliminary results and

  10. The potential use of swelling clays for backfilling and sealing of underground repositories: The case of the Boom clay

    International Nuclear Information System (INIS)

    In Belgium the SCK/CEN is studying the geological disposal of high level radioactive waste in the Boom clay formation. In such an argillaceous repository, the backfilling and sealing features will be multiple: boreholes, shafts, access drifts, disposal galleries or holes and dams. A preliminary selection study screening industrial materials has been performed based on the following criteria: at least as good thermal and hydraulic properties as the in situ Boom clay, sufficient volumetric swelling and swelling pressure, proven geochemical compatibility and stability. This study has shown that swelling clays are the most promising materials. Because of its evident geochemical compatibility and its easy availability, it is a logic choice to study the re-use of the excavated clay. The hydraulic, thermal and geochemical retention and swelling properties of the Boom clay were studied and the results are compared to those of bentonites. The main results of this study are: a hydraulic conductivity as low as 10-13 m/s can be reached which is one order of magnitude lower than that of the in situ Boom clay but is one order of magnitude higher than those of bentonite; the volumetric swelling of the Boom clay is rather limited but a swelling pressure of about 4 MPa can be obtained which is about a factor five lower than for bentonites but also corresponds to the in situ lithostatic pressure; the radionuclide retention properties of the in situ Boom clay are at least as good as those of dense bentonites and are for some nuclides even better; steam drastically reduces the volumetric swelling of bentonites which also leads to a higher hydraulic conductivity. The swelling properties of the Boom clay are also to be affected by steam, but the effect is less dramatic. In particular, its low hydraulic conductivity seems to be conserved. (author). 14 refs, 4 figs, 6 tabs

  11. Experimental research on the strength of cemented backfilling body of waste rocks%废石尾砂胶结充填体强度试验研究

    Institute of Scientific and Technical Information of China (English)

    罗根平; 乔登攀

    2015-01-01

    Experimental study is systematically conducted on cemented backfilling with waste rocks.The paper states the applicability and mechanism of waste rock cemented filling process and focuses on the influencing factors on the strength of cemented filling body of waste rocks,namely the water-cement ratio,cement-sand ratio,cement content, the grading and proportioning of the particle size of waste rocks.The research results show that the lager the water-ce-ment ratio and cement-sand ratio are,the less the strength of cemented backfilling body becomes,contrary to that rela-tion between cement content and the backfilling body's strength.With constant strength,cemented filling with waste rocks consumes less cement per unit volume and cost less than other filling methods.%对废石尾砂胶结充填进行了系统的试验研究。阐述了废石尾砂胶结充填工艺的工业性及原理,着重研究了废石尾砂胶结充填体强度的影响因素:水灰比、灰砂比、水泥含量、废石尾砂的粒径级配及配比。研究结果表明,废石尾砂胶结充填体强度随水灰比、灰砂比的减小而增大,随水泥含量的增加而增加。在强度一定的条件下,废石尾砂胶结充填比其他充填方式,单位体积内水泥耗量少,成本低。

  12. Numerical Study on One-dimensional Frost Heave Amount of Composite Backfill%复合填料一维冻胀量数值模拟分析

    Institute of Scientific and Technical Information of China (English)

    祁生旺; 邓安

    2012-01-01

    A composite backfill is a kind of light backfill formed by mixing waste foundry sand, flyash, expanded polystyrene (EPS) beads, cement and water in designated proportions. Inclusion of EPS beads can reduce or eliminate frost heave and thaw settlement, and thus can be used as backfill of road base in seasonal frost areas. A one-dimensional frost heave model was established based on the current moisture-heat coupling model. The model is able to take account of the elastoplastic behavior of EPS bead and its effect on frost heave taken place within the mass of composite backfill. The results given by the model are in a good agreement with the test results achieved from a previous companion study, which validates the use of this model in the prediction of frost heave of engineering works in seasonal frost areas.%复合填料是以废铸砂、粉煤灰、聚苯乙烯颗粒(EPS)、水泥和水为原料,拌合后形成的一种轻质填筑材料.其中,EPS颗粒含量适当时,能减少或消除复合填料的冻胀和融沉,可作为季节性冻土区的路基填料.假设复合填料中除EPS颗粒外的骨料颗粒、孔隙冰为刚性介质,同时考虑EPS颗粒变形和填料孔隙变形对复合填料冻结过程的影响,在已有的冻土水热耦合分离冰模型的基础上,得到考虑EPS颗粒变形影响的饱和填料一维冻结水热耦合控制方程,进而预测填料的冻胀量.与室内模型试验结果对比表明,本文模型可用于该种具有弹性颗粒复合填料的冻胀量模拟,为工程中冻胀量预测提供依据.

  13. 粉煤灰对矿渣胶结充填材料性能的影响%Influence of Fly Ash Performance of Slag Cemented Backfilling Materials

    Institute of Scientific and Technical Information of China (English)

    董璐; 高谦; 南世卿; 何环莎

    2012-01-01

    In view of the features of fly ash as abundant resources,low costs and improving the construction of mortar, the influence of fly ash on strength and liquidity of slag cemented materials is studied through experiments. The results show that the slag cemented backfilling materials with the lime and desulfurization gypsum as the activator, the compressive strength of backfilling body gradually declined with the adding amount of fly ash increasing. 1% of fly ash is added each time,the intensity decreased by 1. 82% at 7 d and by 1. 61% at 28 d on average. Meanwhile,the yield stress and viscosity of the backfilling is getting lower,which indicates that fly ash can largely improve the rheology of backfilling materials,and make high concentration of mortars conveying by gravity flow. Comprehensively considering the strength and the rheology, the optimal dosage of the fly ash ranges from 10% to 20%.%针对粉煤灰具有来源广、价格低廉和能改善砂浆施工性能的特点,研究了粉煤灰对矿渣胶结充填材料强度和流动性的影响.结果表明:在以石灰和脱硫石膏为激发剂制备的矿渣胶凝材料中,随着粉煤灰添加量的不断增大,充填体的抗压强度逐渐下降,每添加1%的粉煤灰,7d强度平均降低1.82%,28 d强度平均降低1.61%;但是充填料的屈服应力和塑形黏度却在不断降低,说明粉煤灰的添加能够很好地改善充填料浆的流变性,实现砂浆高浓度自流输送.综合考虑强度和流变性的影响效果,粉煤灰的最优掺量范围为10%~ 20%.

  14. Modeling coupled blast/structure interaction with Zapotec, benchmark calculations for the Conventional Weapon Effects Backfill (CONWEB) tests.

    Energy Technology Data Exchange (ETDEWEB)

    Bessette, Gregory Carl

    2004-09-01

    Modeling the response of buried reinforced concrete structures subjected to close-in detonations of conventional high explosives poses a challenge for a number of reasons. Foremost, there is the potential for coupled interaction between the blast and structure. Coupling enters the problem whenever the structure deformation affects the stress state in the neighboring soil, which in turn, affects the loading on the structure. Additional challenges for numerical modeling include handling disparate degrees of material deformation encountered in the structure and surrounding soil, modeling the structure details (e.g., modeling the concrete with embedded reinforcement, jointed connections, etc.), providing adequate mesh resolution, and characterizing the soil response under blast loading. There are numerous numerical approaches for modeling this class of problem (e.g., coupled finite element/smooth particle hydrodynamics, arbitrary Lagrange-Eulerian methods, etc.). The focus of this work will be the use of a coupled Euler-Lagrange (CEL) solution approach. In particular, the development and application of a CEL capability within the Zapotec code is described. Zapotec links two production codes, CTH and Pronto3D. CTH, an Eulerian shock physics code, performs the Eulerian portion of the calculation, while Pronto3D, an explicit finite element code, performs the Lagrangian portion. The two codes are run concurrently with the appropriate portions of a problem solved on their respective computational domains. Zapotec handles the coupling between the two domains. The application of the CEL methodology within Zapotec for modeling coupled blast/structure interaction will be investigated by a series of benchmark calculations. These benchmarks rely on data from the Conventional Weapons Effects Backfill (CONWEB) test series. In these tests, a 15.4-lb pipe-encased C-4 charge was detonated in soil at a 5-foot standoff from a buried test structure. The test structure was composed of a

  15. 矿山废石全尾砂充填研究现状与发展趋势%The directions of R&D on backfill with waste rock and total tailings in underground mine

    Institute of Scientific and Technical Information of China (English)

    王贤来; 姚维信; 王虎; 乔登攀; 程伟华; 张磊

    2011-01-01

    矿产资源开发过程中产生的废石、尾砂和冶炼渣,等占我国工业固体废料排放量的85%左右.大量矿山固体废料堆放地表,易造成严重污染,诱发泥石流、尾矿溃坝事故.固体废料充填工艺是解决矿山废尾排放的最有效途径.本文介绍了低浓度分级尾砂充填、全尾砂高浓度充填、膏体似膏体充填、块石胶结充填工艺的研究与应用现状,并分析了矿山废石全尾砂充填技术的研究与发展方向.%The waste rock, tailings and smelter slag in the process of the exploitation of mineral resources accounted the industrial solid wastes for about 85% in China based on traditional mining pattern. A large number of the solid waste pilled up on the ground in mine can cause serious pollutions, and may induce mudflows and tailings dam-break accidents. Undoubtedly, the solid waste backfill is the most effective way to solve the discharge of mine waste. In this paper, the present situation of research and application of several filling technology are described with regard to low-density classified tailings backfill, high-density total tailings backfill, paste and like paste backfill, as well as rock cemented backfill. Furthermore, the directions of R&D on backfill with waste rock and total tailings in underground mine were analyzed.

  16. M4FT-16LL080303052-State of Knowledge for Colloid Facilitated Radionuclide Transport and Update on Actinide Diffusion in Bentonite Backfill

    Energy Technology Data Exchange (ETDEWEB)

    Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Glenn T. Seaborg Inst.. Physical and Life Sciences; Joseph, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Glenn T. Seaborg Inst.. Physical and Life Sciences

    2016-08-16

    This progress report (Level 4 Milestone Number M4FT-16LL080303052) summarizes research conducted at Lawrence Livermore National Laboratory (LLNL) within the Crystalline Disposal R&D Activity Number FT-16LL080303051 and Crystalline International Collaborations Activity Number FT-16LL080303061. The focus of this research is the interaction of radionuclides with Engineered Barrier System (EBS) and host rock materials at various physico-chemical conditions relevant to subsurface repository environments. They include both chemical and physical processes such as solubility, sorption, and diffusion. The colloid facilitated transport effort focused on preparation of a draft manuscript summarizing the state of knowledge and parameterization of colloid facilitated transport mechanisms in support of reactive transport and performance assessment models for generic crystalline repositories. This draft manuscript is being submitted as a level 3 milestone with LANL as the primary author. LLNL’s contribution to that effort is summarized only briefly in the present report. A manuscript summarizing longterm U(VI) diffusion experiments through bentonite backfill material was recently accepted for publication; the contents of that manuscript are summarized in the present report. The Np(IV) diffusion experiments were started mid-year and are ongoing. The completion of these experiments is planned for early FY17. Our progress in quantifying Np(IV) diffusion in bentonite backfill is summarized in the present report. Our involvement with the NEA TDB project was summarized in a recent Argillite Disposal activity report. It is not included in this report.

  17. Experimental research on backfill sand foundation treatment of artificial islands%人工岛吹填砂地基处理试验研究

    Institute of Scientific and Technical Information of China (English)

    张虎平; 胡殿才

    2012-01-01

    Combining with the vibration load of the oil drilling platform and the requirement for earthquake resistance protection,the paper undertakes the experiment research on the foundation treatment of the backfill sand foundation of some artificial island,and proves by the result that it is better to adopt the vibroflotation method to treat the backfill sand with the thickness more than 7.0 m and the dynamic consolidation can be adopted for the one with the thickness less than 7 m and with lower underground water level,so as to provide the reliable reference for the following large foundation treatment.%结合石油钻井平台振动荷载及抗震设防要求,对某人工岛吹填砂地基进行了地基处理试验研究,结果表明:采用振冲密实法处理厚度大于7.0 m的吹填粉砂效果较好,而厚度小于7 m且地下水位较低时也可采用强夯法,为后续大面积地基处理提供了可靠的依据。

  18. Groundwater recovery experiment in Mizunami Underground Research Laboratory. Numerical simulation of H-M coupled behavior of rock and backfill materials to evaluate the influence on the surrounding rock

    International Nuclear Information System (INIS)

    In the Mizunami Underground Research Laboratory, groundwater recovery experiment is being conducted to develop the method to understand the transition of geological environment due to groundwater recovery at the -500 m access and research gallery-north. As a part of this experiment, backfill test is planned using drilling pits filled with artificial materials (clay and concrete) to evaluate the influence on the surrounding rock mass due to the interaction of rock and artificial materials. In this study, numerical simulation of the backfill test has been carried out to predict the qualitative hydro-mechanical behavior. (author)

  19. Aespoe Hard Rock Laboratory. Prototype Repository. Analyses of microorganisms, gases and water chemistry in buffer and backfill, 2009

    Energy Technology Data Exchange (ETDEWEB)

    Lydmark, Sara (Microbial Analytics Sweden AB (Sweden))

    2010-09-15

    chemistry. The in 2007 improved sampling and analysis protocols worked very well. Also, the molecular methods that were tested for the first time in the Prototype showed promising potential. IPR 08-01 revealed that many of the hydrochemical sampling points differ quite remarkably from each other. The 16 sampling points were therefore divided into seven sampling groups with similar properties. The properties of one sampling group (i.e., KBU10002+8) resembled those of the groundwater, while others (i.e., KBU10004+6, KBU10005, and KFA01-04) differed, for example, in microbial composition, salinity, sulphate content, pH, and the concentrations of calcium, potassium, magnesium, sodium, and many dissolved metals, actinides, and lanthanides. One sampling group contained sampling points that seemed to be in contact with tunnel air (KBU10003+7). Another sampling group contained sampling points near the canisters in the buffer (KB513-614) with very little pore water with high pH and a high salt content. One sampling point in the backfill, which had not been reached by the groundwater as of May 2007 (KBU10001), now consisted of pore water with properties resembling those of groundwater. The gas composition in the sampling groups was uniform in that the proportion of nitrogen in the extracted gas was increasing and the oxygen content decreasing with time. In most sampling groups, the oxygen content in the pore water had decreased from 3-7% as of May 2007 to 0.6-4% in 2009. This can also be compared with the proportion of oxygen in the gas phase in 2005, which was 10-18%. Hydrogen, methane, helium, and carbon dioxide concentrations varied, especially in the sampling groups with extractable pore water. ATP analyses demonstrated that the biomass in the Prototype repository is high compared to the surrounding groundwater. The microbiological results indicated that aerobic microbes, such as MOB and CHAB, thrived in the aerobic Prototype environment

  20. 复合填料热传导过程数值模拟%Numerical Simulation of Heat Conduction in Composite Backfill

    Institute of Scientific and Technical Information of China (English)

    方鑫; 邓安

    2012-01-01

    复合填料由废铸砂、粉煤灰、聚苯乙烯(EPS)颗粒、水泥和水按一定质量比例混合制成,具有低导热性、抗冻胀和轻质特性.根据热阻力法则和比等效导热系数相等法则,将材料视为由大量正方形单元体组成,其中心为一个球形EPS颗粒,这种单元体与总体的导热系数相等.运用ANSYS软件对复合填料单元体的传热过程进行了有限元模拟,根据瞬态法导热系数测试原理,推求不同EPS掺入比情况下的复合填料导热系数,分析EPS颗粒与导热系数的关系,发现材料导热系数随着EPS掺入比的增加而快速降低.将材料导热系数数值模拟与实测结果作比较,发现有限元模拟值与实测值接近,说明采用有限元方法可以实现对材料传热过程的模拟.%A composite backfill is described in this study, which is composed of waste foundry sand, fly ash, expanded polystyrene (EPS) bead, cement and water in designated proportions, and takes the advantage of low thermal conductivity, frost resistance and light weight. Based on the thermal resistance law and the law of ratio effective thermal conductivity, a simplified model was established, which treats the composite matrix as numerous heat transfer cubic elements which are physically contacted to transfer heat. A spherical EPS bead is centered in an element, which is surrounded by cemented earth material. Finite element (FE) analysis was conducted to simulate the heat transfer taken place through the element, and to estimate the thermal conductivity of the backfill by using ANSYS software package. It is indicated that the thermal conductivity of the backfill decreases with the increase of EPS content. The test results were well simulated by the FE results.

  1. Influence of pressure conditions and back-filling materials on the durability of bore-hole ground loops; Lebensdauer von Erdwaermesonden in Bezug auf Druckverhaeltnisse und Hinterfuellung

    Energy Technology Data Exchange (ETDEWEB)

    Rohner, R. [E. Rohner, Arnegg (Switzerland); Rybach, L.; Salton, M. [Swiss Federal Institute of Technology (ETHZ), Institut fuer Geophysik, Zuerich (Switzerland)

    2001-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) discusses the influence of the relatively high pressures found in ground loops at depths of more than 200 metres and the effects caused by overloading the ground loops. The latter can cause the back-filling between the ground loop and the surrounding rock to freeze. The report describes tests carried out on 70-metre and 265-metre deep test bore-hole installations. The results of investigations into the influence of such pressure conditions on the materials of the ground loop and their service life are presented. The results are also compared with simulations using the FRACTure and EED calculation programmes. Details are given on the bore-holes with respect to their geology and construction. The report concludes that bore-hole ground loops can be considered as being very robust components with a long service life, provided they are designed and installed according to accepted professional standards.

  2. 土工袋技术在市政沟槽回填中的应用研究%Application of soilbags to urban trench backfill

    Institute of Scientific and Technical Information of China (English)

    刘斯宏; 高军军; 王子健; 王柳江; 胡晓平

    2014-01-01

    市政工程中管线埋入地下采用的基本流程是先开挖沟槽,将开挖的原土作为渣土处理,待管线在沟槽中安放后再用二灰土石填埋沟槽,经夯实后铺设沥青或混凝土路面。为了有效利用沟槽开挖土、减少二灰土石用量,建议采用土工袋技术处理,即将沟槽开挖土装入土工编织袋后回填至沟槽中。阐述了土工袋技术原理,并依托南京市雨污分流工程,对用土工袋回填的沟槽进行了平板载荷试验、落锤式挠度检测和路面振动测试,评价土工袋沟槽的回填效果。结果表明:土工袋在提高沟槽承载力、减少沉降变形、削弱交通振动干扰等方面具有明显效果。土工袋避免弃土外运,减少了扬尘污染,不失为一种绿色、环保、经济的工程新技术。%The basic way to bury pipelines into ground in the municipal projects is:excavating a trench firstly, and throwing away the excavated soils as wastes; backfilling the expensive lime-ash soil into the trench after the pipelines are placed properly; tamping foundation and laying asphalt or concrete pavements. In consideration of recycling the excavated soils and reducing the use of lime-ash soil, soilbag technique is suggested in urban trench backfills so as to cut down the project costs. The mechanism of soilbag technique is briefly elucidated herein; and several field tests such as plate loading test, falling-weight deflection and vibration response measurements are then carried out respectively to evaluate the benefits of a soilbag-trench, with the strong support of the Rain and Sewage Diversion Project in Nanjing. The test results show that soilbag technique performances superbly in improving the bearing capacity of subgrade, decreasing the settlement of roadbed as well as in reducing and isolating the traffic-induced vibrations, compared with the common backfill scheme. It is also proved that backfilling the trench with soilbags is a

  3. Strength evolution and deformation behaviour of cemented paste backfill at early ages:Effect of curing stress, filling strategy and drainage

    Institute of Scientific and Technical Information of China (English)

    Ghirian Alireza; Fall Mamadou⇑

    2016-01-01

    In this study, a pressure cell apparatus is developed to investigate the early age evolution of the strength and deformation behaviour of cemented paste backfill (CPB) when subjected to various loading condi-tions under different curing scenarios. The different curing scenarios that are simulated include: (1) drained and undrained conditions, (2) different filling rates, (3) different filling sequences, and (4) differ-ent curing stresses. The findings show that drainage, curing stress, curing time and filling rate influence the mechanical and deformation behaviours of CPB materials. The coupled effects of consolidation, drai-nage and suction contribute to the strength development of drained CPB subjected to curing stress. On the other hand, particle rearrangement caused by the applied pressure and suction development due to self-desiccation plays a significant role in the strength gain of undrained CPB cured under stress. Furthermore, curing stress induces slightly faster rate of cement hydration, which can contribute to strength acquisition.

  4. Evaluation of the effect of sodium silicate addition to mine backfill, Gelfill – Part 2: Effects of mixing time and curing temperature

    Directory of Open Access Journals (Sweden)

    M. Kermani

    2015-12-01

    Full Text Available The effects of mixing time and curing temperature on the uniaxial compressive strength (UCS and microstructure of cemented hydraulic fill (CHF and sodium silicate-fortified backfill (Gelfill were investigated in the laboratory. A series of CHF and Gelfill samples was mixed for time periods ranging from 5 min to 60 min and cured at temperatures ranging from 5 °C to 50 °C for 7 d, 14 d or 28 d. Increasing the mixing time negatively influenced the UCS of Gelfill samples, but did not have a detectable effect on CHF samples. The curing temperature had a strong positive impact on the UCSs of both Gelfill and CHF. An elevated temperature caused rapid UCS development over the first 14 d of curing. Mercury intrusion porosimetry (MIP indicated that the pore size distribution and total porosity of Gelfill were altered by curing temperature.

  5. On grouting strengthening construction of gravel soil back-filled foundation%碎石土回填基础灌浆补强施工

    Institute of Scientific and Technical Information of China (English)

    陶旭东

    2012-01-01

    针对某取水泵站投入运行后场区碎石土回填基础出现沉降的原因进行了分析,通过研究比选采用灌浆加固方案,对灌浆施工关键点及特殊情况处理进行了阐述,以保证场区稳定、安全。%The paper analyzes the reasons for the settlement of the gravel soil back-filled foundation at the site after some pumping station was op erated, and illustrates the key points for the grouting construction and some treatment for some special circumstances by comparing and analyzing the grouting consolidation schemes, so as to ensure the site to be stable and safe.

  6. Evaluation of the effect of sodium silicate addition to mine backfill, Gelfill e Part 2:Effects of mixing time and curing temperature

    Institute of Scientific and Technical Information of China (English)

    M. Kermani; F.P. Hassani; E. Aflaki; M. Benzaazoua; M. Nokken

    2015-01-01

    The effects of mixing time and curing temperature on the uniaxial compressive strength (UCS) and microstructure of cemented hydraulic fill (CHF) and sodium silicate-fortified backfill (Gelfill) were investigated in the laboratory. A series of CHF and Gelfill samples was mixed for time periods ranging from 5 min to 60 min and cured at temperatures ranging from 5 ?C to 50 ?C for 7 d, 14 d or 28 d. Increasing the mixing time negatively influenced the UCS of Gelfill samples, but did not have a detectable effect on CHF samples. The curing temperature had a strong positive impact on the UCSs of both Gelfill and CHF. An elevated temperature caused rapid UCS development over the first 14 d of curing. Mercury intrusion porosimetry (MIP) indicated that the pore size distribution and total porosity of Gelfill were altered by curing temperature.

  7. 江西省某冶炼厂遗留尾砂场重金属污染特征%Evaluation on heavy metal pollution of backfilling fields of a melting factory in Jiangxi

    Institute of Scientific and Technical Information of China (English)

    丁凝; 刘建明; 孙峰

    2014-01-01

    By using single -factor pollution index method and Nemerow index method,the paper mainly investigates into the heavy metals( Pb,Cd,Cu,Zn,Cr,Ni,As)content and pollution on the backfilling fields in a melting factory of JiangXi. The backfilling fields were used to contain waste residue generated from the melting production. The result indicated that all the backfilling fields had a highly standard-exceeding content of Cu ,Zn,Ni,and As in soil. Except the deep soil of back-filling field No. 2,soils in other sampling spots contained heavy metals with their comprehensive pol-lution index higher than 1 ,implying soils in all backfilling fields were seriously contaminated by heavy meatless.%以江西省某冶炼厂生产过程中遗留在厂内各尾砂池中的废渣为研究对象,利用单因子污染指数法和内梅罗综合污染指数法相结合的方法对其重金属污染状况进行评价。结果表明:各尾砂池土壤中铜、锌、镍、砷超标倍数高,且除尾砂池2深层土壤外,其他样点重金属内梅罗综合污染指数均远大于1,显示各尾砂池土壤均为重污染土壤。

  8. Aespoe Hard Rock Laboratory. Prototype repository. Analyses of microorganisms, gases, and water chemistry in buffer and backfill, 2010

    Energy Technology Data Exchange (ETDEWEB)

    Lydmark, Sara [Microbial Analytics Sweden AB, Moelnlycke (Sweden)

    2011-06-15

    therefore divided into seven sampling groups, each with similar properties. The properties of one sampling group (i.e. KBU10002 + KBU10008) resembled those of the groundwater, while others (i.e. KBU10004 + KBU10006, KBU10005, and KFA01-KFA04) differed, for example, in microbial composition, salinity, sulphate content, and the concentrations of calcium, potassium, magnesium, sodium, and many dissolved metals, actinides, and lanthanides. One sampling group comprised sampling points that seemed to be in contact with tunnel air (KBU10003 + KBU10007). Another sampling group comprised sampling points, near the canisters in the buffer (KB513-614), with very little pore water with high pH and a high salt content. One sampling point in the backfill, which had not been reached by the groundwater as of May 2007 (KBU10001), now yielded pore water with properties resembling those of groundwater. The gas composition in the sampling groups was uniform in that the proportion of nitrogen in the extracted gas was increasing while the oxygen content was decreasing with time. ATP analyses demonstrated that the biomass in the Prototype was higher than in the surrounding groundwater. The microbiological results indicated that aerobic microbes, such as methane-oxidizing bacteria and culturable heterotrophic bacteria, thrived in the aerobic Prototype environment. The chemical data indicated differences between the sampling groups: concentrations of sodium and potassium were higher in the Prototype pore water than in the groundwater outside it, while calcium was lower than in the groundwater. Obviously, cation exchange occurs in the montmorillonite interlayers. At sampling points containing active microbes, copper, rubidium, vanadium, and uranium were enriched up to 225 times the groundwater levels; microbes are possibly responsible for dissolving these substances by excreting compound-specific ligands. Overall, the observations presented here strongly support our hypothesis that oxygen will be

  9. 全尾砂新型充填胶凝材料开发及其水化机理探讨%Discussion on exploitation of new backfilling cementing materials with unclassified tailings and associated hydration mechanisms

    Institute of Scientific and Technical Information of China (English)

    李茂辉; 杨志强; 高谦; 王有团

    2015-01-01

    Based on the characteristics of unclassified tailings in the Sijiaying iron mine, experimental research on exploitation of new backfilling cementing materials that can replace the cement was carried out using lime, desulfurization gypsum, slag, and other solid wastes. Using scanning electron microscopy ( SEM) and X⁃ray diffraction ( XRD) analysis, the hydration mechanisms of the new backfilling cementing materials were analyzed, and the optimum ratio of activators was determined. The results show that the strength of the new backfilling cementing materials can meet the filling body strength requirements for safe mining in the Sijiaying iron mine when the mass fractions of slurry, lime, and desulfurization gypsum are 68%, 3. 5%, and 16. 0%, respectively, and the cement⁃sand ratio is 1∶8. The results also show that the new backfilling cementing materials have a more compact structure and coarser occurrence when compared with the cement. The hydration products of the new backfilling cementing materials are mainly AFt crystals and C⁃S⁃H gel, which greatly increases the age strength of the new backfilling cementing materials.%针对司家营铁矿全尾砂,利用石灰、脱硫石膏、矿渣等固体废弃物开展替代水泥的新型充填胶凝材料试验研究,并通过电镜扫描( SEM)和X射线衍射( XRD)分析,研究新型充填胶凝材料激发剂的水化机理,确定激发剂优化配比。研究表明,当料浆质量分数为68%、胶砂比为1∶8、石灰质量分数为3.5%、脱硫石膏质量分数为16.0%时能够满足司家营铁矿南区嗣后充填法采矿对充填体强度的要求。结果显示,新型充填胶凝材料胶砂体与水泥胶砂体相比,结构更致密、产状更粗大,水化产物主要为AFt晶体和无定型C⁃S⁃H凝胶,从而大幅度提高了新型充填胶凝材料胶砂体的龄期强度。

  10. Determination of internal pressure and the backfill gas composition of nuclear fuel rods; Determinacion de la presion interna y la composicion del gas de llenado de barras de combustible nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Garcia C, M.A.; Cota S, G.; Merlo S, L.; Fernandez T, F. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    An important consideration in the nuclear fuel manufacturing is the measurement of the helium atmosphere pressure and its composition analysis inside the nuclear fuel rod. In this work it is presented a system used to measure the internal pressure and to determine the backfill gas composition of fuel rods. The system is composed of an expansion chamber provided of a seals system to assure that when rod is drilled, the gas stays contained inside the expansion chamber. The system is connected to a pressure measurement digital system: Baratron MKS 310-AHS-1000. Range 1000 mm Hg from which the pressure readings are taken when this is stabilized in all the system. After a gas sample is sent toward a Perkin Elmer gas chromatograph, model 8410 with thermal conductivity detector to get the corresponding chromatogram and doing the necessary calculations for obtaining the backfill gas composition of the rod in matter. (Author)

  11. Analysis of Impacts on Earthquake Response of Intake Tower by Backfill Concrete on Tower Back%塔背回填混凝土对进水塔地震响应的影响分析

    Institute of Scientific and Technical Information of China (English)

    李锋

    2015-01-01

    塔背回填混凝土将岸塔式进水塔和山岩连成一体,提高了进水塔整体刚度,有效改善了塔体在地震情况下的拉应力幅值,对进水塔结构的抗震设计非常关键。以某水电站的岸塔式进水塔为例,针对不同高度塔背回填混凝土的塔体模型进行三维有限元静动力计算,以分析回填混凝土对进水塔地震响应的影响。%The backfill concrete on the tower back integrates the intake tower and the mountain rockmass, increasing the overall rigidity of the intake tower and effectively improving the tensile stress range value of the tower body in earthquake condition.This is very important for the aseismic design of the intake tower structure.With the case of the intake tower of one hydropower station, the static and dynamic calculations in 3D finite element method are performed to the tower models with the backfill concrete on the tower back at different heights so as to analyze the impacts on the earthquake response of the intake tower by the backfill concrete on the tower back.

  12. 采空区回填体隧道冒顶塌方处理技术%Treatment Technology on Roof Fall and Landslide of Backfilled Tunnel in Goaf

    Institute of Scientific and Technical Information of China (English)

    谈东亚

    2014-01-01

    以铜陵市五松隧道在施工中遇到的采空区回填体塌方处理为例,针对采空区回填体导致冒顶塌方的特点,从安全顺利的角度,通过临时环向竖向钢支撑加固未塌方段、套管法超前管棚超前预支护、水泥水玻璃注浆加固、预留核心土法开挖支护、回填轻质混凝土、换拱等技术,安全顺利地处理完该塌方,为今后类似工程提供一定的参考。%Based on the example of treatment on backfilled landslide in goaf encountered in Wusong Tunnel construction in Tongling,according to the characteristics of goaf backfilling roof fall and landslide,from the safety angle,measures are used to deal with the landslide,like temporary reinforcement of the sound section with circumferential vertical steel support,ad-vanced support with cuff shed pipe,grouting reinforcement with cement water glass,reservation core soil excavation,backfill-ing of light weight concrete,arch replacement technology,so as to provide references for similar projects in the future.

  13. 核子密度仪在阿曼管沟回填中的应用%Use of nuclear density gauge for testing trench backfilling in Oman

    Institute of Scientific and Technical Information of China (English)

    邓兆勋; 刘光然

    2011-01-01

    针对国际工程——阿曼马斯喀特污水管网工程点多、面广、管沟回填速度快、检测频率高等特点,阐述了核子密度仪的工作原理,依据英国BS标准进行校正的方法及针对阿曼政府对辐射源的管理所采取的防护措施,保证了工程质量和施工的顺利进行。%Considering Oman Muscat waste water collection network project——an international construction project which has many engineering aspects,requirement of quick backfilling and fast detection,high test frequencies,this article explains the working principle of the nuclear density gauge,according to the British BS standard method of correction and focusing on the management of the government of Oman to the radiation protection measures taken to ensure the engineering quality and construction to proceed smoothly.

  14. Size effect of compressive strength of cemented backfill%胶结充填体力学强度尺寸效应

    Institute of Scientific and Technical Information of China (English)

    彭志华

    2009-01-01

    本文通过尾砂胶结充填体配比试验,研究了尾砂胶结充填体强度与试样尺寸和几何形状之间的关系.试验研究结果表明:在相同条件下,胶结充填体强度在试验范围内,随试样尺寸的增加而减小,其呈非线性变化;不同尺寸与几何形状的胶结充填体试样强度之间的换算比例关系为:152mm充填体试样强度大致为72mm和85mm试样强度的3/4,为70.7mm立方体试样强度的3/5.%This paper researches relation of compressive strength of cemented tailings fill and size、geometries of cemented backfill. The test results show under same condition compressive strength of cemented tailings fill will minish with size increasing, it show itself non-linear variety. 150mm diameter cylinder specimen fill strength averaged approximately three-quarter of 72mm and 85mm diameter cylinders specimen, about three fifths of 70.7mm cubes specimen.

  15. Research and Development of a New Silica-Alumina Based Cementitious Material Largely Using Coal Refuse for Mine Backfill, Mine Sealing and Waste Disposal Stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Henghu Sun; Yuan Yao

    2012-06-29

    Coal refuse and coal combustion byproducts as industrial solid waste stockpiles have become great threats to the environment. To activate coal refuse is one practical solution to recycle this huge amount of solid waste as substitute for Ordinary Portland Cement (OPC). The central goal of this project is to investigate and develop a new silica-alumina based cementitious material largely using coal refuse as a constituent that will be ideal for durable construction, mine backfill, mine sealing and waste disposal stabilization applications. This new material is an environment-friendly alternative to Ordinary Portland Cement. The main constituents of the new material are coal refuse and other coal wastes including coal sludge and coal combustion products (CCPs). Compared with conventional cement production, successful development of this new technology could potentially save energy and reduce greenhouse gas emissions, recycle vast amount of coal wastes, and significantly reduce production cost. A systematic research has been conducted to seek for an optimal solution for enhancing pozzolanic reactivity of the relatively inert solid waste-coal refuse in order to improve the utilization efficiency and economic benefit as a construction and building material.

  16. National waste terminal storage repository in a bedded salt formation for spent unreprocessed fuel. Special study No. 3. Waste retrieval from backfilled regions

    International Nuclear Information System (INIS)

    Methods and costs were studied for delayed canister retrieval from rooms that had been backfilled immediately after canister storage. The effects of this method of storage on mine geometry, thermal and rock mechanics environments, mine development and operations, mine ventilation, time schedule, retrieval machinery and safety were investigated. Salt and air temperatures were determined. Pillar width, number of rooms, extraction ratio, tonnages of mined salt, and salt handling and hoisting requirements were calculated. The required changes in mining equipment were established. Salt handling and elapsed time schedules were developed. Ventilation requirements - size and number of shafts, size the arrangement of airways, number of stacks, and size and number of fans were then calculated. The development sequence of these facilities was established. Canister retrieval problems were analyzed for canisters stuck in the hole as well as free. Retrieval methods and machinery were studied and are described. Safety with respect to both radiation and room collapse was studied and compared with CDR safety conditions. The effects of a reduced themal loading of 30 KW/acre on temperatures, room closure, mine layout, ventilation and ground control were studied and reported. A cost estimate was prepared, giving cost differentials between the base CDR costs and Special Study No. 3. Two appendices are included. The first contains nine Heat Transfer memoranda that state the thermal basis of this study. The second appendix provides a detailed operating time analysis of the retrieval machinery

  17. Reduced clay bearing gray sandstone deposits of Meghalaya, NE India: a possible upper backfill material in geological repository for high level radioactive waste Disposal

    International Nuclear Information System (INIS)

    Geology and geochemical aspects of reduced clay rich gray sandstones of Cretaceous age hosting anomalous uranium occurrences in Meghalaya plateau have been evaluated to assess their suitability as lower backfills in far field region of the geological repository. These sandstones are chiefly made up of quartz (70-90%) and contain appreciable amount of clays and organic matters. Geochemical data on these sandstones indicates that actinides (U and Th), elements analogues to fission products (Rb, Sr, Zr, Mo, Nb, Cd, Ag, Cs, Ba and rare earth elements are adequately retained in clays and organic matters associated with these deposits. Albeit these clay rich (Illite-Smectite-Kaolinite) sandstones contain almost 30 % water-soluble uranium and lies in one of the highest rainfall area of the world, not much uranium and other trace elements have been reported to escape from the geological set up and hydrogeological system. Due to the presence of strong reducing environment prevailing in these rocks caused by the presence of pyrite and organic matter, most of the uranium being dissolved by circulatory oxygenated groundwater gets reduced and also is trapped in the organic matter as organo uranyl complexes. The organic matters in these sandstones have total adsorption capacity of 0,5% for actinides and at time contains as high as 40% uranium adsorbed form groundwater. Similarly it also contains as high as 193-ppm molybdenum, 458-ppm cadmium and 35-ppm silver. Data also reveals that most of the organic matter has been subjected to temperature more than 100 C in the geological past during its burial and diagenesis, hence possibility of carbon dioxide production consequent to waste emplacement also does not exists. The clays in these sandstones reveal good retention capacity for uranium, radium, rubidium, strontium, cesium and rare earth elements, whereas most of the barium appears to have been accommodated in secondary calcite frequently available in these sandstones

  18. 堤坝下矸石不升井充填采煤技术实践%Application of solid backfill mining under dams avoiding raising waste rock

    Institute of Scientific and Technical Information of China (English)

    李剑; 王东升; 王志平; 康涛; 耿佃凯

    2013-01-01

      Aimed at exploiting coal resources under dams safely and efficiently and disposing of gangue excavated underground on a large scale of Jisan coal mine ,Yankuang Group ,this paper presented a solution of solid backfilling mining avoiding raising waste rock .According to mining geological conditions in pilot area of Jisan coal mine and structural characteristics of Nanyang Lake Dam ,proposed a method of gangue preprocessing and transport from advancing face to backfilling working face .Based on technical characteristics of backfilling mining ,developed four key equipments in backfilling working face :four‐link backfill supports with six props ,backfilling conveyor with a bunch of unloading holes at the bottom ,a full coal seam compactor and a self‐shift transshipping conveyor .According to the protection requirement of Nanyang Lake Dam ,determined the security technical measures of filling ratio .When mining was completed at 63下 04‐1 working face ,the maximum sinking value of the Nanyang Lake Dam was 32mm and the maximum horizontal deformation value was 0 .14mm/m ,which were both far lower than the predicted value and the dam's deformation extremum ,both Nanyang Lake Dam and the buildings around had not occurred crazing damage .%  为达到兖矿集团济三煤矿堤坝下压煤资源的安全高效开采及井下掘进矸石规模化处理的目的,提出采用矸石不升井充填采煤技术开采堤坝下压煤。根据济三煤矿试验区域采矿地质条件及南阳湖堤结构特点,设计了矸石由掘进工作面至充填采煤工作面的预处理和运输方案;基于充填采煤的工艺要求,研发了充填采煤工作面4种关键设备:正四连杆六柱式固体充填采煤液压支架、多孔底卸式输送机、全采高夯实机和自移式充填物料转载输送机;依照南阳湖堤保护要求,确定了充填采煤充实率保障技术措施。63下04‐1工作面按照设计方案开采完毕后,实测

  19. Structure model and movement law of overburden during strip pillar mining backfill with cream-body%条带煤柱膏体充填开采覆岩结构模型及运动规律

    Institute of Scientific and Technical Information of China (English)

    陈绍杰; 郭惟嘉; 周辉; 温国惠

    2011-01-01

    Space-time structure model and movement law of overburden were researched during strip pillar mining backfill with cream-body,taking 2351 backfilling face for an example.The results show that as the face advances,overburden strata are gradually transformed from the "C" type space structure into articulated rock beam with unequal height supports.The immediate roof of working face is the main roof;the first weighting interval is 33.6 m,and the periodic weighting length respectively are 18.3,8.8,13.7 and 9.0 m for the last four times.The overburden gravity mainly acted on coal wall in front of face and backfill paste,which had little effect on roof advance stress,and the influence scope is less than 15 m.In current technology conditions of face 2351,the reasonably maximal roof control distance is 8.8 m,the reasonable working resistance of support backfilling is 27 MPa,and the support setting load is 21 MPa.%以岱庄煤矿2351膏体充填工作面为例,研究了条带煤柱膏体充填开采覆岩时空结构模型及运动规律。结果表明:随着工作面的推进,覆岩由"C"型空间结构逐渐转化成不等高支撑的铰接岩梁;工作面的直接顶板即为基本顶,初次来压步距33.6 m,前4次周期来压步距分别为18.3、8.8、13.7、9.0 m;覆岩重力主要作用在工作面前方煤壁和充填膏体上,顶板超前应力和影响范围较小,主要影响范围小于15 m;2351工作面在现行工艺技术条件下,最大合理控顶距为8.8 m,充填支架合理工作阻力为27 MPa、合理初撑力为21

  20. Research on Protecting the Safety of Buildings by Using Backfill Mining with Solid%利用固体充填开采方法保护建筑群安全的研究

    Institute of Scientific and Technical Information of China (English)

    徐惠

    2012-01-01

    我国煤矿建筑物下压煤量占总压煤量的69%,同时每年要向地面排放4.5亿t以上的固体废弃物,因此,研究利用固体废弃物充填开采方法,在保证地表建筑物安全性的基础上,高效开采出下压煤炭资源意义重大.文章应用数值模拟方法,对建筑物下压煤开采所引起的岩层移动过程进行模拟,系统分析了采场围岩塑性区分布及地表沉陷量变化规律,由计算结果分析得知,应用固体充填开采法与无充填直接开采相比,采场围岩破坏单元数较少,围岩稳定性受影响较小,减少地表沉陷量效果明显.以数值模拟结果作为参考,研制了长臂综采矸石充填开采工艺的配套设备,并在某矿建筑物下压煤炭开采的实际应用中取得良好效果,有效控制了地表变形,保证了建筑物的安全性和资源的高效开采.%The coal under buildings accounts for 69% of the total in China,while more than 4.5 billion tons of solid waste is discharged to the ground over years.This paper studied the backfill with solid mining method.It is meaningful for the efficient exploitation of coal mining under buildings as well as reducing environmental pollution around the mining area.In this paper,we analyzed the plastic zone distribution of the face surrounding rock and the variation of surface subsidence systematically.According to the simulation results,backfill mining with solid reduce the damage to the surrounding rock of the goaf and diminish the effect on the stability of surrounding rock.It also can reduce the surface subsidence obviously.Taking the above study results as one of the important references,we research and design the matching equipments with fully-mechanized filling mining.The filling equipments mainly are the self-tamping backfilling hydraulic support and backfilling conveyor.These have been applied to an actual exploitation of coal mining under buildings,and achieved good results.It can control the surface

  1. 高瓦斯矿井高水材料充填墩柱沿空留巷技术%Gateway Retained Along Goaf Technology with Pier Pillar Backfilled with High Water Material in High Gassy Mine

    Institute of Scientific and Technical Information of China (English)

    史国跃

    2014-01-01

    In order to improve a high timber consumption,high labor intensity,complicated construction and low support strength of the timber pack gateway retained along the goaf,a high water material was applied to backfill the pier pillar for the gateway retained along the goaf technology in Gaohe Mine and the industrial trial was conducted in No. E1302 air return gateway.The results showed that the max convergence between the roof and floor of the timber pack gateway retained along the goaf was 286 mm,the max convergence between the roof and floor of the gateway retained along the goaf with the pier pillar backfilled with the high water material was 188 mm and the max deformation value of the pier pillar was 65 mm.The construction technology of the gateway retained along the goaf with the pier pillar backfilled with the high water material was simple.The compressive strength of the pier pillar was high and could control the deformation of the surrounding rock.Meanwhile,the ventilation cross section enlarged of the mine roadway would be favorable for the ventilation gas discharging and could prevent the gas accident occurred in the mine.%为了改善木垛沿空留巷木料消耗量大、劳动强度高、施工复杂、支护强度较低的问题,高河煤矿采用了高水材料充填墩柱沿空留巷技术,并在E1302回风巷进行了工业性试验。结果表明:木垛沿空留巷顶底板最大移近量为286 mm,采用高水材料充填墩柱沿空留巷技术顶底板最大移近量为188 mm,墩柱最大变形量为65 mm,高水材料充填墩柱沿空留巷技术施工工艺简单、墩柱抗压强度大,可有效控制围岩变形,同时增大巷道通风断面有利于风排瓦斯,防止矿井发生瓦斯事故。

  2. Subsidence prediction method based on equivalent mining height theory for solid backfilling mining%基于等价采高理论的固体充填采煤沉陷预计方法

    Institute of Scientific and Technical Information of China (English)

    郭广礼; 朱晓峻; 查剑锋; 王强

    2014-01-01

    Based on the characteristics of strata movement of solid backfilling mining technology, the surface subsidence prediction method based on the equivalent mining height theory was proposed, and the parameters selection guideline of this method was also described. While comparing the parameters of caving mining with equivalent height, the subsidence efficient can be calculated according to the mining height and bulk factor of sagging zone and fracture zone, the tangent of main influence angle of solid backfilling mining is reduced by 0.2-0.5 (while it cannot be less than 1.0). For sake of safety, offset of the inflection point is set to zero, and other parameters, such as horizontal movement coefficient and main propagation angle are equal to the corresponding parameters of caving mining with equivalent height. In the last part, a case study of solid backfilling mining subsidence prediction was described. The results show the applicability of this method and the difference of the maximum subsidence point between the prediction and the observation is less than 5%.%在分析固体充填采煤岩层移动特征的基础上,提出固体充填采煤沉陷预计方法,并给出概率积分法参数选取方法。研究认为:与等价采高煤层垮落法开采下沉系数相比较,固体充填采煤沉陷预计参数中下沉系数可以根据垮落带、裂隙带的高度以及碎胀率计算得出;主要影响角的正切略小0.2~0.5,但不应小于1.0;出于安全考虑,拐点偏移距离可为零;水平移动系数和下沉影响角可不变。最后,利用基于等价采高理论的概率积分法模型计算了花园煤矿固体充填的地表沉陷。结果表明,该方法较为可靠地预测了固体充填的地表沉陷,最大下沉点的预计误差不超过5%。

  3. Fatigue Analysis on Pallet of Chain Type Feeder System for Backfill Mining%充填采煤链式投料系统托盘疲劳分析

    Institute of Scientific and Technical Information of China (English)

    张国伟; 马占国; 耿敏敏; 龚鹏

    2011-01-01

    According to the importance of the pallet in the chain type feeder system for the backfill mining,with the calculation formula of the impact load provided with the energy method,a finite element program was applied to study on the fatigue damage of the pallet after the impact of the backfill material under the different spaces and different dropping velocities and to predict the fatigue life of the pallet.Finally the dangerous part of the pallet was analyzed and the fatigue law of the pallet affected by the impact of the backfill material was obtained.The study results showed that with the space between the pallets increased,the fatigue damage of the pallet would be higher and when the space between pallets was 5 m,the fatigue life would meet the mining service life of the mine.The higher of the pallet dropping velocity,the fatigue damage of the pallets could be reduced.In consideration of the strength,stability and transportation efficiency of the pallet,the dropping velocity of 1.5~2.5 m/s would be suitable.%针对托盘在充填采煤链式投料系统中的重要性,通过能量法得出冲击载荷计算公式,利用有限元程序对托盘在不同间距、不同下降速度下,受充填材料冲击后的疲劳损伤进行研究,预测了托盘的疲劳寿命。最后分析了托盘的危险部位,得到托盘受充填材料冲击的疲劳规律。研究结果表明:随着托盘间距增大,托盘疲劳损伤越大,托盘间距取5 m时其疲劳寿命符合煤矿开采年限;托盘下降的速度越大,其受到的疲劳损伤减少,考虑到托盘的强度、稳定性、运输效率,选取其速度为1.5~2.5 m/s较合适。

  4. Explore the Problems of Municipal Water Supply Pipeline Trench Excavation and Backfill%市政给水管道沟槽开挖及回填问题的研究

    Institute of Scientific and Technical Information of China (English)

    覃永和

    2014-01-01

    随着城市化进程的加快,城市给水管网改造工程也在不断的增多。本文主要就市政给水管网改造工程中的给水管道沟槽开挖及回填问题进行了研究,以提高给水管网改造工程的质量。%With the speeding up of urbanization, the reconstr-uction project of urban water supply pipeline network has in-creased. This article mainly carries on the exploration of the water supply pipe trench excavation and backfil problems in the municipal water supply pipeline network reconstruction en-gineering, in order to improve the quality of the water supply pipe network project.

  5. Environmental assessment of the reuse of municipal solid waste incineration bottom ash in quarry backfilling; Evaluation environnementale de la valorisation de machefers d'incineration d'ordures menageres en remplissage de carriere

    Energy Technology Data Exchange (ETDEWEB)

    Brons-Laot, G.

    2002-10-15

    The leaching behaviour of three different MSWI bottom ashes-based materials containing hydraulic binders is assessed in the conditions specified by the quarry backfilling application. An adapted approach methodology is applied: - physical, mineralogical and chemical characterizations of materials, - use of parametric tests to determine the effect of main scenarios factors on the release, - chemical modelling based on mineralogical and experimental leaching data with geochemical calculation codes, - chemical reaction / transport coupled modelling. The main results demonstrate that: - the batch and dynamic tests allow to obtain enough data to model and to predict the long term behaviour, - the chemical modelling of the solid / liquid equilibrium permits the determination of the chemical reactions involved and the prediction of pollutants solubilization in different chemical contexts, - the new materials (source term) present a low environmental impact in the conditions specified by the considered scenarios. (author)

  6. Experimental study on workability of soil-bentonite backfills for vertical slurry cutoff walls%土膨润土系竖向隔离墙材料施工和易性试验研究

    Institute of Scientific and Technical Information of China (English)

    梅丹兵; 杜延军; 刘松玉; 范日东; 杨玉玲

    2016-01-01

    为研究满足各类场地条件下土膨润土系竖向隔离墙材料施工和易性要求的主要施工参数,对钙基膨润土浆液和钠基膨润土浆液进行马氏漏斗黏度试验、API滤失试验和密度测定,并针对砂膨润土、黏性土膨润土、砂黏性土膨润土3类土膨润土系竖向隔离墙材料进行坍落度试验.试验结果表明,钙基膨润土浆液和钠基膨润土浆液的合理膨润土掺量分别为10%和3%.3类土膨润土系竖向隔离墙材料的坍落度与含水率均呈良好的线性正相关性.采用标准坍落筒和迷你锥坍落筒所测定的坍落度结果之间存在统一的经验关系.采用迷你锥坍落筒代替标准坍落筒进行土膨润土系竖向隔离墙材料施工和易性试验时,满足坍落度要求的含水率范围为其液限的1.0~1.6倍,所对应坍落度范围为22~48 mm.%In order to investigate the main construction parameters that meet the workability of soil-bentonite backfills for vertical slurry cutoff walls under various types of site conditions, the marsh fun-nel test, API(American Petroleum Institute) filtrate loss test and density measurement for sodium ben-tonite-water slurries and calcium bentonite-water slurries were carried out.The slump tests of three soil-bentonite backfills, including sandy soil-bentonite, clayey soil-bentonite sandy and soil-clayey soil-bentonite backfills, were measured.The experimental results show that the suitable contents of bentonite for calcium bentonite-water slurries and sodium bentonite-water slurries are 10% and 3%, respectively.The slumps of three soil-bentonite backfills and the water content exhibit a good linear positive correlation.And there exists a uniform correlation between the results based on the standard slump cone and those based on the miniature slump cones.When the standard slump cone is replaced by the miniature slump cone, the water content meeting the requirements of the slump is

  7. Development of On-line Monitoring System of Paste Backfill in the Goaf%采空区膏状充填体在线监测系统研制

    Institute of Scientific and Technical Information of China (English)

    张新国; 江宁; 江霞; 江兴元

    2011-01-01

    Gangue gream-body filling is the main technological means of realizing green mine and the best technology to solve the problem of mine under water body, building and rail, and on karst water body and to control surface subsidence, which used the surface movement observation to evaluate the filling effect in the past,but cycle is often longer,cost is higher and amount of labour is larger using the mood of surface movement observation. To this point, developed the on-line monitoring system of paste backfill in the goaf, based on the KJ216 monitoring system of plank pressure. Comprehensively evaluated the filling effect through long-term monitoring of long-term stress, deformation and hydration degree of paste backfill in the goaf. The practice showed that the system worked well on site.%作为实现“绿色开采”的主要技术手段和当前解决“三下一上”压煤问题,控制地表沉陷效果最好的矸石膏体充填开采技术,其充填效果评价过去一直采用的是地表岩移观测的方式,但是采用地表岩移观测的方式周期往往较长、费用较高、劳动量大.为此,基于K(J216顶板压力在线监测系统,研制了采空区膏状充填体在线监测系统.对采空区膏状充填体长期受力、变形和水化程度进行长期监测,综合评价充填效果.实践证明该系统现场应用效果良好.

  8. 用充填技术促进矿山资源开发与环境保护协调发展%Coordinated Development between Mineral Resource Exploitation and Environmental Protection with Backfill Technology

    Institute of Scientific and Technical Information of China (English)

    苏亮; 张小华

    2013-01-01

    阐述了资源开发与环境保护的矛盾,提出了矿山资源开发与环境保护协调发展的主要目标及途径.将充填技术应用于资源-经济-环境体系中,根据矿山固体废弃物料的特点,对不同的固体废弃物料采用废石充填、尾砂充填和矿碴灰充填等不同的充填工艺技术,不仅提高了矿产资源的利用率,而且降低了矿山废弃固体物料对环境的污染.%In view of the contradiction occurred between mineral resources exploitation and environmental protection,technology of backfilling with waste rocks,tailing sand and slags according to different types of solid mine wastes is proposed to be adopted for achieving coordinated development of mineral resources exploitation and environmental protection.Practice shows such technology can not only improve the utilization of mineral resources,but also reduce the adverse effect of mining waste on environment.

  9. 风积砂质高浓度胶凝充填材料性能与粉煤灰掺量关系分析%RELATIONSHIP BETWEEN ENGINEERING PERFORMANCE AND MIX PROPORTION OF FLY ASH FOR CEMENTED AND HIGH CONCENTRATION BACKFILL MATERIAL WITH WIND-BLOWN SAND AS AGGREGATE

    Institute of Scientific and Technical Information of China (English)

    王晓东

    2016-01-01

    In coal mining with backfill,backfill material dominates the benefit,efficiency and effect.In order to get the characteristics varying pattern of cemented and high concentration backfill material with wind-blown sand as aggregate,fly ash is selected as variables to test and analyze the characteristics varying pattern of backfill material with the mix proportion of fly ash.The results show that,as the mix proportion of fly ash increases in a proper range in backfill material,the compressive strength increases,the bleeding rate decreases in general,the layered degree declines by linear pattern,the coagulation time grows up by exponential pattern,and the slump is growing consecutively.But,with the higher mix proportion of fly ash,the compressive strength and slump will drop comparatively.When the mix proportion of fly ash is in proper range,the fly ash optimizes the particle size gradient of backfill material,and makes water and cement distribution uniform in backfill material.As a result,the strength characteristic and rheological performance can be improved.However,some characteristics will degenerate with higher mix proportion of fly ash.%充填材料是决定煤炭充填开采效益、效率、效果的最主要因素.为了掌握风积砂质高浓度胶凝充填材料的性能变化规律,本文以粉煤灰的质量掺入比作为变量,试验研究和理论分析了粉煤灰对该充填材料性能的影响规律.结果表明,粉煤灰的适量添加可以提高充填材料的强度,大掺量导致强度相对降低;泌水率随着粉煤灰掺量的增大总体上呈减小趋势,较大掺量试样泌水速率相对较低;分层度随着粉煤灰掺量的增大线性降低;凝结时间随着粉煤灰掺量增大呈现指数增大;坍落度总体上随粉煤灰掺量的升高而增大,但大掺量会使其出现相对降低.分析认为,适量粉煤灰的掺入,使风积砂质高浓度胶凝充填材料的颗粒粒度、水分分布和水泥分散均匀,而使材

  10. 高放废物地质处置库中缓冲回填材料的收缩特征%Shrinkage characteristics of buffer-backfilling materials in high-level radioactive waste geological disposal

    Institute of Scientific and Technical Information of China (English)

    唐朝生; 施斌; 崔玉军

    2012-01-01

    The shrinkage characteristics of buffer-backfilling materials play an important role in the security and stability of the high-level radioactive waste geological disposal system. COx argillite is considered as a kind of potential buffer-backfilling materials in France. In this investigation, both the initially saturated compacted COx specimens and the paste-like COx specimens are prepared and subjected to different test methods to study their volumetric shrinkage behaviours. For the compacted specimens, it is found that the volumetric shrinkage deformation is significantly influenced by the initial dry density; the shrinkage limit, shrinkage efficiency and shrinkage strain decrease with the increasing dry density; in addition, it is observed that the shrinkage direction of specimens shows obvious anisotropism. For example, at low degree of compaction, the radial shrinkage strain is higher than axial shrinkage strain, and the shrinkage geometry factor is larger than 3; however, the contrary results are obtained at high degree of compaction. For the paste-like specimens, three shrinkage stages can be distinguished: normal shrinkage, residual shrinkage and zero shrinkage; most of the volume shrinkage deformation occurs before the air-entry point while the soil is still fully saturated. A group of four general shrinkage models are employed to fit the shrinkage curve of the paste-like specimens. The results show that the G & C model can get the highest performance for the present soil.%缓冲回填材料的收缩特征对高放废物处置库的安全性和稳定性有重要影响。以COx泥岩缓冲回填材料为研究对象,采用不同的试验方法分别研究了饱和的压实试样和糊状试样在干燥过程中的体积收缩变形特征。试验结果表明:压实试样的体积收缩变形特征受初始干密度的影响比较明显,缩限、收缩系数和收缩应变均随初始干密度的增加而减小;压实试样的体积收缩

  11. 强夯+CFG桩复合地基在较厚回填土中的应用%Application of dynamic compaction and CFG pile composite foundation in the treatment of thick backfill

    Institute of Scientific and Technical Information of China (English)

    郑宇; 王天勇; 杨铮; 金灿国; 王建华; 张相勇; 董素芹

    2013-01-01

    The design and construction method of dynamic compaction plus cement fly-ash grave ( CFG) pile were introduced to enhance the bearing capacity of foundation and control foundation settlement in thick backfill by an engineering example. The standard penetration test and static loading test were carried out to topsoil compacted by dynamic compaction, and the bearing capacity of the composite foundation processed by dynamic compaction and CFG was detected by static loading test of single pile composite foundation and vertical compression static loading test of single pile. The results show that the bearing capacity and deformation of composite foundation are acceptable and can meet the requirement of related codes. Moreover, the engineering example shows this method can shorten the construction period and is economic, convenient and safe.%通过工程实例,介绍了在较厚回填土中采用强夯+ CFG桩复合地基进行地基处理以提高地基承载力及控制沉降的设计及施工方法.强夯后对表层土进行标准贯入试验及静力载荷试验,打入CFG桩后对复合地基承载力进行单桩复合地基静载荷试验与单桩竖向抗压静载荷试验检测,结果表明地基承载力与变形均满足规范要求.工程实例表明采用此方法可节约造价、缩短工期且安全可靠.

  12. Research on Backfilling Friction Stir Spot Welding of LY12 Al Alloy%LY12铝合金回填式搅拌摩擦点焊工艺研究

    Institute of Scientific and Technical Information of China (English)

    王朗; 王敏; 郭立杰

    2013-01-01

    采用回填式搅拌摩擦点焊对1mm厚的LY12铝合金薄板进行焊接,研究单参数对接头拉剪力的影响.结果表明,在其他条件不变时,套下压时间影响接头U型区域的宽度,套下压时间为3.2s时,接头的拉剪力达到最大值;其他参数对U型区域深度产生影响;回填时间为0.4s、旋转速度为1500r/min、下压深度为1.1mm、焊接压力为23 MPa时接头的拉剪力均达到最大值.正交试验工艺优化结果表明,最佳的工艺参数组合为:套下压时间为3.6s、回填时间为0.9s、旋转速度为2400r/min、下压深度为1.1mm、压力为24 MPa.对最佳参数组合下的接头进行金相分析,发现接头区域分为三个部分:混合区、热影响区和母材.%The backfilling friction stir spot welding to weld 1 mm-thick LY12 aluminum alloy plate was adopted, and the single parameter on the effect of joint's shear load was investigated. The results show that when other conditions remain unchange, pressure time affect the width of the joint area. When pressure time is 3.2 s, joint's shear load reach maximum; other parameters affect the depth of the joint area; when refilling time is 0.4 s, rotating speed is 1500 r/min, depth is 1.1 mm, pressure is 23MPa, joint's shear load reaches maximum. After the optimization of process parameters, the orthogonal test results show that the best process parameter combination is pressure time 3.6s, refilling time 0.9s, rotating speed 2400 r/m, depth 1.1 mm, pressure 24 MPa. The metallographic analysis of the welded joint at the best parameters found that the joint area is divided into three parts: mixed zone, heat affected zone and mother material.

  13. 煤矿膏体充填材料性能随龄期变化的试验研究%Experimental study on the changes of coal paste backfilling material performance during hydration process

    Institute of Scientific and Technical Information of China (English)

    戚庭野; 冯国瑞; 郭育霞; 张玉江; 任昂; 康立勋; 郭军

    2015-01-01

    Coal paste backfilling material (CPBM) is composed of coal gangue, flyash, ordinary port-land cement and tap water. In order to identify the properties of each raw material, the mineral composi-tion, chemical composition of coal gangue flyash have been analyzed;the compressive strength, porosi-ty and electrical resistivity have been studied at different curing times. The samples taken from curing time of 7 d, 14 d and 28 d, have been evaluated for their mineral composition and microstructure. The law of CPBM property with increasing curing time has been analyzed, and the correlation among the compressive strength, porosity, resistivity and hydrating process has also been deeply discussed. The results indicate that firstly, with the curing time increasing, compressive strength and electrical resistiv-ity are increasing, while porosity and small pore content are reducing. Secondly, hydrated and poz-zolanic reaction occur in the change of CPBM property, with calcium hydroxide, C-S-H gel and ettring-ite being the reaction products. The calcium hydroxide crystal is only found at the curing time of 7 d, not at 14 d and 28 d, and the types and quantities of ettringite crystal at 28 d are more than at 7 d and 14 d. The crystal structure of 28 d presented more slender with the curing time increasing. Thirdly, the hy-drated and pozzolanic reaction are the two primary reasons causing the change of performance of CPBM strength with the change of curing time. Moreover,there is some interrelation between the per-formances.%煤矿膏体充填材料(CPBM)由煤矸石、粉煤灰、水泥和水为原料混合而成。为了了解各原料的性质,对煤矸石和粉煤灰的矿物组成、化学成分进行了分析,对固定配比CPBM在不同龄期的抗压强度、孔隙率和电阻率性能进行了研究,测定和观测7,14和28 d的矿物成分和微观结构;针对抗压强度、孔隙率、电阻率和水化过程之间存在的相关性进行了

  14. Multi-objective Modeling and Simulation of Mining Backfill Scene%多目标建模技术及煤矿充填开采场景仿真

    Institute of Scientific and Technical Information of China (English)

    张国英; 梁旭; 张智跃

    2015-01-01

    矿山信息化建设是煤矿企业实现现代化发展的必然趋势.煤矿充填开采是一个复杂的过程,为了解决实现采煤充填过程最优化的问题,对开采场景进行仿真是一个直观而有效的解决方法.煤矿充填开采场景仿真不仅让人们更加深刻地了解开采实际生产环境,而且方便指导现场生产以及矿工安全培训,实现煤矿信息化、数字化.由于煤矿充填系统场景复杂、设备繁多、数据量大,实时仿真的技术难度较大.设计了场景树组织模型,有效组织充填开采场景要素.提出了基于设备组件分析及分层的复杂设备建模方法,以液压支架为例阐述了设备建模过程.提出了基于场景树的场景装配方法,包括场景环境生成、设备资源组织,用相对坐标方法进行资源装配,实现了充填开采的场景仿真.%Mine informationization is an inevitable trend to realize the modernization of coal mine enterprises. Mine filling mining is a complex process,in order to solve the problem to realize the optimization of the filling process of coal mining,the mining scene simula-tion is an effective method. Simulation of mining backfill scene not only makes people more understanding the actual mining environment of exploiting,but also easily guides on-site production and miners training,to realize informationization and digitization of coal mine. Be-cause of complex scenes,large volumes of equipment and data in mine filling system,the work of scene simulation is heavy,especially for real-time simulation technology. Design scene tree of filling mining, effectively organizing scene elements of filling. Complex device modeling method was presented in this paper,which includes the equipment' s components analysis and layer,with hydraulic support as an example to discuss the equipment modeling processing. Scene' s assembly method was proposed based on scene tree,including scene' s environment generation and equipment resources

  15. 运用强夯法处理港口开山碎石土回填地基的应用实践%Application Practice of Using Dynamic Consolidation Method to Process Port Backfill Foundation of Mountain Gravel Soil

    Institute of Scientific and Technical Information of China (English)

    张大旭

    2014-01-01

    对开山碎石土回填的地基,采用强夯法进行加固处理,可以改变地基结构排列、使其致密,从而提高地基承载力。强夯能起到深层地基加固、减少地基沉降量、提高地基承载力的作用,是一种经济有效的地基处理方法。%Using the dynamic compaction method to reinforce the backfil foundation of mountain gravel soil, can change the structure, making it tight, to improve the bearing capacity of foundation. The dynamic compaction has the role to reinforce deep foundation, reduce the set lement of foundation, increase the bearing capacity of the foundation, is an economical and effective foundation treatment method.

  16. 西石门矿地下尾矿库安全回填项目环境影响及对策%Impacts of Backfilling Mine Tailings on Environment and a New Approach to Reduce Adverse Impacts of Xishimen Mine

    Institute of Scientific and Technical Information of China (English)

    钱金平

    2001-01-01

    The disposal of tailings is a key technical core for mining. Xishimen mine is adopting advanced technology for treating subterranean tailings by secondary concentration and dehydration. The treated tailings of mine could then be safely backfilled into underground, facilitating reducing adverse environmental impacts of mining.%介绍了西石门铁矿尾矿安全回填工程的基本情况,分析了地下尾矿库的库体安全性及环境影响并提出了相关对策。结论认为,西石门矿采用地下尾矿库技术,最大程度地减少了地面尾矿库对环境产生的不良影响,有利于尾矿库区的生态恢复。

  17. 30 CFR 816.102 - Backfilling and grading: General requirements.

    Science.gov (United States)

    2010-07-01

    ... stability, and control erosion on final-graded slopes, if the terraces are compatible with the approved... this section; (3) Achieve a postmining slope that does not exceed either the angle of repose or such lesser slope as is necessary to achieve a minimum long-term static safety factor of 1.3 and to...

  18. Compression Characteristics of Solid Wastes as Backfill Materials

    Directory of Open Access Journals (Sweden)

    Meng Li

    2016-01-01

    Full Text Available A self-made large-diameter compression steel chamber and a SANS material testing machine were chosen to perform a series of compression tests in order to fully understand the compression characteristics of differently graded filling gangue samples. The relationship between the stress-deformation modulus and stress-compression degree was analyzed comparatively. The results showed that, during compression, the deformation modulus of gangue grew linearly with stress, the overall relationship between stress and compression degree was approximately nonlinear, and the deformation of gangue was rather large during the initial portion of the test. Gangue sample mixed with Talbot Formula provides the best deformation resistance capacity, followed by fully graded and single-graded gangue samples. For applications, with adjustment of the gradation of filling materials and optimal design of compacting equipment, surface subsidence may be better controlled.

  19. 30 CFR 817.102 - Backfilling and grading: General requirements.

    Science.gov (United States)

    2010-07-01

    ... to conserve soil moisture, ensure stability, and control erosion on final-graded slopes, if the... include a terrace of adequate width to ensure the safety, stability, and erosion control necessary to...; (4) Minimize erosion and water pollution both on and off the site; and (5) Support the...

  20. 30 CFR 715.14 - Backfilling and grading.

    Science.gov (United States)

    2010-07-01

    ... regulatory authority and in order to conserve soil moisture, ensure stability, and control erosion on final... include a terrace of adequate width to ensure the safety, stability, and erosion control necessary to... control over erosion and closely resemble the surface configuration of the land prior to mining. In...

  1. Mass transfer of soluble species into backfill and rock

    International Nuclear Information System (INIS)

    This report describes a mathematical model that estimates the rate that cesium and iodine isotopes would migrate from spent fuel rods after emplacement in a geologic repository that is subsequently flooded with ground water. 4 refs., 2 figs

  2. Draft Test Plan for Brine Migration Experimental Studies in Run-of-Mine Salt Backfill

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Amy B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stauffer, Philip H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reed, Donald T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boukhalfa, Hakim [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Caporuscio, Florie Andre [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Robinson, Bruce Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-02

    The primary objective of the experimental effort described here is to aid in understanding the complex nature of liquid, vapor, and solid transport occurring around heated nuclear waste in bedded salt. In order to gain confidence in the predictive capability of numerical models, experimental validation must be performed to ensure that (a) hydrological and physiochemical parameters and (b) processes are correctly simulated. The experiments proposed here are designed to study aspects of the system that have not been satisfactorily quantified in prior work. In addition to exploring the complex coupled physical processes in support of numerical model validation, lessons learned from these experiments will facilitate preparations for larger-scale experiments that may utilize similar instrumentation techniques.

  3. Load Bearing and Deformation Characteristics of Granular Spoils under Unconfined Compressive Loading for Coal Mine Backfill

    Directory of Open Access Journals (Sweden)

    Guodong Li

    2016-01-01

    Full Text Available The load bearing capacity and deformation response of granular spoils under uniaxial compression are numerically and experimentally investigated, aiming to shed light on the performance of back filled waste spoils while controlling ground subsidence after coal extraction. In numerical study, the particles are assembled in PFC commercial code in light of the digitized real shape of spoils with image technique, which is proved to be consistent with the physical test. The results from numerical and laboratory experiments showed that the complete compressive process of spoils tended to have spatial and temporal characteristics. The load-strain curves of investigated specimens could be divided into three stages (stage I, rearranging stage; stage II, breaking stage; stage III, consolidating stage and three zones (I, rearranging zone; II, interlocking zone; III, consolidated zone from outside to inside. During stage I, the load increasing rate of smaller spoils is relatively low, but it increases faster than larger ones in stages II and III. In addition, spoils with Talbot’s gradation are greater than single gradations. The magnitude of the density in consolidated zone is maximum, indicating that it is the main part holding the overlying strata weight.

  4. Study of backfilling of fissures in granite by precipitation of silica

    International Nuclear Information System (INIS)

    The discharge of high-activity radioactive wastes in granitic formations heats the rock in the area of the waste repository. Silica, a constituent of granite, may be dissolved by subterranean water in the heated area and reprecipitated in the colder outer zone. The aim of this study is to quantify this phenomenon experimentally and to assess its extent and effects by means of a numerical model

  5. Placement of pre-compacted and in situ compacted dense backfill materials in shaft seals

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In 2003, a decision was made to discontinue operation of Atomic Energy of Canada Limited's (AECL's) Underground Research Laboratory (URL) and ultimately to decommission and permanently close the underground portion of this facility. As part of the Nuclear Legacy Liability Program (NLLP) being funded by Natural Resources Canada (NRCan), an ongoing program of work is being undertaken to decommission and deal with facilities that are no longer part of AECL's mandate or operations. The URL is included in these facilities. Part of this work is the installation of seals at the intersection of the access and ventilation shafts and an ancient thrust fault, Fracture Zone 2 (FZ2), approximately 275 m below surface. These seals are being installed in order to limit the potential for mixing of deeper saline and shallower, less saline groundwater. The seal design in each shaft is similar with a heavily reinforced lower concrete component, a central bentonite clay-sand component and an upper un-reinforced concrete component. The main shaft at the URL at the location of the seal is circular (∼5-m diameter), and was excavated using careful drill and blast techniques. The seal itself consists of two keyed, conical sectioned, 3-m-thick by 5 to 6-m diameter concrete segments that confine a 6-m-thick swelling clay section. The ventilation shaft at the URL is 1.8 m in diameter and was excavated using raise-boring. The ventilation shaft will consist of two keyed, conical sectioned, 2-m-thick concrete by 1.8 to 2.8 m diameter concrete segments confining a 5-m-thick assembly of pre-compacted clay-sand blocks. The concrete is a low pH concrete designed for repository use, which can develop a 70 MPa unconfined compressive strength after 28 days. It has a pH of less than 11 achieved by substitution of 75% of the cement powder with silica fume and ground silica so the likelihood of free calcium and an alkaline plume is greatly reduced. The concrete provides confinement for the swelling clay. Two approaches were taken for the central clay unit in each seal. The main shaft uses compacted in situ clay-based material with 40% dry mass Wyoming sodium bentonite (200 mesh gradation), and 60% uniform gradation, water washed sand (< 2% of - 200 mesh size), with a target dry density of 1.80 ± 0.05 Mg/m3. The ventilation shaft uses pre-compacted clay blocks composed of 70% Kunigel V1 bentonite and 30% uniform gradation, water washed sand. These blocks were originally prepared in 1998 for the Tunnel Sealing Experiment (TSX) and unused materials were stored underground under plastic sheets. The blocks were designed to be hand placed and are approximately 35 cm x 10 cm x 18 cm in size which is convenient for use in construction of the ventilation shaft seal. In situ compaction required pre-blending of the clay-based material in order to achieve a clay component that is homogeneous with respect to density and initial degree of saturation. Because of the volume involved and in order to test a technique that is both time and cost efficient regarding material preparation, a conventional concrete dry batching truck was utilized. An auger on the truck blended the raw materials, with a water tank supplying the required water. The resulting material was bagged and stored for use once it was quality checked. Clay was delivered to the seal location in the main shaft once the lowermost concrete portion of the seal was cured for 28 days. The bagged clay was transferred to a shaft clam-shell bucket and transported to the seal location and then dumped. The clay material was manually spread to an initial ∼20 cm thickness for compaction and once compaction was completed each lift was approximately 10 cm in thickness. The clay volume in the shaft is approximately 117 m3 (6-m-thick). Compaction was accomplished by use of two relatively small, hand-operated impact compactors. Along the perimeter of the shaft (and in areas where instrument cables were installed) a smaller impact compactor was used. The compaction and other construction operations needed to be conducted carefully as the concrete, clay and surrounding rock mass of main shaft seal are being monitored via a suite of approximately 60 sensors that record temperature, strain, hydraulic and mechanical pressure as well as water content within the seal. Hand tamping was performed immediately around the cables as necessary to protect them. This paper presents the details of the work completed in the main shaft of late fall of 2009. The ventilation shaft clay placement will involve a volume of approximately 13 m3 and utilize techniques developed in the TSX. Blocks will be cut as required and field fitted into the space where the seal is located. Granular or pelletized bentonite will be poured and compacted as space permits at the perimeter in any gaps that remain after block installation. This seal will not be monitored but past work has indicated that low hydraulic conductivities can be achieved under a high hydraulic gradient for clay seal components constructed from pre-compacted blocks. The operational experiences and lessons learned from installation of both clay barrier types will be discussed in the paper. (authors)

  6. Performance of concrete backfilling materials for shafts and tunnels in rock formations

    International Nuclear Information System (INIS)

    Preplaced Aggregate Concrete (PAC) consists of graded coarse aggregate, placed and packed into position, and then immobilised by cementitious grout injected into the voids between the aggregate pieces. PAC is also reported to be amenable to mechanical/ remote placement and have usefully improved properties when compared with conventionally placed concretes. This study attempts to establish the validity of these claims both from reported experience and by practical demonstration through experimentation. A literature study supported the claims made for the PAC system but all reported experiences recorded the use of organic admixtures in order to obtain the improved concrete properties. Because of the lack of long term durability data on such admixtures especially in a radiation environment, it was decided to prepare a sample of PAC without organic admixtures. Considerable experimental difficulties were encountered in obtaining a satisfactory quality 1m cube of PAC from which test specimens could be cut. The necessary grout fluidity was only achieved by the inclusion of bentonite. The test data collected indicates that the PAC system employed on this occasion did not improve either the short term or longer term mechanical properties compared with conventional concretes. (author)

  7. Cemented backfilling technology with unclassified tailings based on vertical sand silo

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A new technology characterized by rapidly non-mechanical settlement of unclassified tailings was developed based on a large number of tests,and dynamic settlement and continual slurry preparation without hardening in vertical sand silo were eventually realized by the addition of an effective flocculating agent (NPA).The results show that the sedimentation velocity of interface between unclassified tailings and water after the addition of NPA increases by 10-20 times,the sedimentation mass fraction of unclassified tailings at the bottom of vertical sand silo is up to 64%,the solid particle content of waste water meets the national standard,and the side influences of NPA can be removed by the addition of fly ash.The industrial test result shows that the system,the addition manner and the equipments are rational,and the vertical sand silo is used efficiently.This developed system is simple with large throughput,and the processing cost is 2.2 yuan(RMB)/m3,only 10%-20% of that by mechanical settlement.

  8. Geochemical studies of backfill aggregates, lake sediment cores and the Hueco Bolson Aquifer

    Science.gov (United States)

    Thapalia, Anita

    This dissertation comprises of three different researches that focuses on the application of geochemistry from aggregates, lake sediment cores and Hueco Bolson Aquifer. Each study is independent and presented in the publication format. The first chapter is already published and the second chapter is in revision phase. Overall, three studies measure the large scale (field) as well as bench scale (lab) water-rock interactions influenced by the climatic and anthropogenic factors spans from the field of environmental geology to civil engineering. The first chapter of this dissertation addresses the chemical evaluation of coarse aggregates from six different quarries in Texas. The goal of this work is to find out the best geochemical methods for assessing the corrosion potential of coarse aggregates prior to their use in mechanically stabilized earth walls. Electrochemical parameters help to define the corrosion potential of aggregates following two different leaching protocols. Testing the coarse and fine aggregates demonstrate the chemical difference due to size-related kinetic leaching effects. Field fines also show different chemistry than the bulk rock indicating the weathering impact on carbonate rocks. The second chapter investigates zinc (Zn) isotopic signatures from eight lake sediment cores collected both from pristine lakes and those impacted by urban anthropogenic contamination. Zinc from the natural weathering of rocks and anthropogenic atmospheric pollutants are transported to these lakes and the signatures are recorded in the sediments. Isotopic analysis of core samples provides the signature of anthropogenic contamination sources. Dated sediment core and isotopic analysis can identify Zn inputs that are correlated to the landuse and population change of the watersheds. Comparison of isotopic data from both pristine and urban lake sediment core also serves as an analog in other lake sediment cores in the world. The third chapter studies on Hueco Bolson Aquifer that an important sources of water in the El Paso/Cd. Juraez metroplex. To delineate the boundary between fresh and brackish water from the northern Hueco Bolson Aquifer, we utilize an integrative geochemical, geophysical, and sedimentological approach. The goal of this study is to use geophysical well-log analysis and the water chemical analysis for identifying the changes in the quality of the groundwater. A detailed microgravity survey is utilized to explore the subsurface geological structures that control the conduits and/or barriers of groundwater flow. A detailed geochemical analysis of aquifer samples provide salinity of groundwater that will complement to the subsurface structures obtained from the geophysical study. This fundamental research in developing methods from an integrated approach to estimate aquifer quality can be used as an analog for similar studies in other arid regions.

  9. Mineralogical, chemical and physical study of potential buffer and backfill materials from ABM. Test Package 1

    Energy Technology Data Exchange (ETDEWEB)

    Kumpulainen, S.; Kiviranta, L. (B and Tech Oy, Helsinki (Finland))

    2011-07-15

    In the ABM experiment, three test packages with centre steel heaters surrounded by stacks of compacted bentonite rings of various clay materials were placed in boreholes in Aespoe tunnel. The first parcel was saturated with Aespoe groundwater and the heater was turned on simultaneously with the start of saturation. This parcel was excavated 30 months after its installation. Chemical, mineralogical and physical properties of the MX-80, Dep-CaN, Asha and Friedland clay samples from the ABM parcel 1 were analysed and compared to reference samples. Chemical analyses (ICP-AES, C, CO{sub 3}, S, water soluble SO{sub 4}, Fe2+/Fe3+), exchangeable cation analyses, mineralogical analyses (XRD, FTIR) and selective extractions were used to determine changes in the chemistry and mineralogy of ABM materials. Swelling pressure and hydraulic conductivity measurements were performed both for extracted samples and for ground and recompacted samples. Major changes in exchangeable cation composition were observed in all samples originating from equilibration with Aespoe groundwater and interactions with equilibrated waters from neighbouring block materials. Some minor changes in chemical composition were observed as well. Increases in soluble sulphate content in the vicinity of the heater were thought to result from precipitation of sulphate salts. Decreases in sodium content and increases in calcium content were ascribed to changes in exchangeable cations. Interaction with iron was observed to occur only in the close vicinity (first few mm) of the heater. No significantly measureable change in mineralogical composition was seen in any of the studied materials. Extracted Dep-CaN samples showed a slight decrease in swelling pressure. However, when the material was ground, compacted and measured again the swelling pressure was fully recovered. No related change in hydraulic conductivities was observed. (orig.)

  10. Application of a Backfilling Method in Coal Mining to Realise an Ecologically Sensitive “Black Gold” Industry

    OpenAIRE

    Xiaowei Feng; Nong Zhang; Lianyuan Gong; Fei Xue; Xigui Zheng

    2015-01-01

    China, as the largest coal-producing and -consuming country in the world, is highly dependent on its coal industry, or “Black Gold” industry, for the national energy and economy. The consequent environmental crises, however, have persisted for decades, and the most serious effect is surface subsidence induced by underground mining. Underground coal excavation in China has ignored this problem for thousands of years, even though it causes conspicuous damage to the surface ecosystem and constru...

  11. An experimental investigation of the temperature behavior of a CANDU 37-element spent fuel bundle with air backfill

    International Nuclear Information System (INIS)

    As part of the thermal analysis of a CANDU spent fuel dry storage system, a series of experiment has been conducted using a thermal mock-up of a simulated CANDU spent fuel bundle in a dry storage basket. The experimental system was designed to obtain the maximum fuel rod temperature along with the radial and axial temperature distributions within the fuel bundle. The main purpose of these experiments was to characterize the relevant heat transfer mechanisms in a dry, vertically oriented CANDU spent fuel bundle, and to verify the MAXROT code developed for the thermal analysis of a CANDU spent fuel bundle in a dry storage basket. A total of 48 runs were made with 8 different power inputs to the 37-element heater rod bundle ranging from 5 to 40 W, while using 6 different band heaters power inputs from 0 to 250 W to maintain the basket wall at a desired boundary condition temperature at the steady state. The temperature distribution in a heater rod bundle was measured and recorded at the saturated condition for each set of heater rod power and band heaters power. To characterize the heat transfer mechanism involved, the experimental data were corrected analytically for radiation heat transfer and presented as a Nusselt number correlation in terms of the Rayleigh number of the heater rod bundle. The results show that the Nusselt number remains nearly constant and all the experimental dada fall within a conduction regime. The experimental data were compared with the predictions of the MAXROT code to examine the code's accuracy and validity of assumptions used in the code. The MAXROT code explicitly models each representative fuel rod in a CANDU fuel bundle and couples the conductive and radiative heat transfer of the internal gas between rods. Comparisons between the measured and predicted maximum fuel rod temperatures of the simulated CANDU 37-element spent fuel bundle for all 48 tests show that the MAXROT code slightly over-predicts and the agreement is within 2.8 % with a mean deviation of 3.2/circ C. Based on the above results, it is concluded that the MAXROT code can be used in the second step of the two-step thermal analysis method, proposed to obtain the maximum fuel rod temperature of the CANDU 37-element spent fuel bundle within a fuel basket in a given spent fuel dry storage canister with an uncertainty of about 2.8 %

  12. Laboratory Study on the Use of Tire Shreds and Rubber-Sand in Backfilled and Reinforced Soil Applications

    OpenAIRE

    Bernal, Andres; Lovell, C. W.; Salgado, Rodrigo

    1996-01-01

    Millions of scrap tires are discarded annually in the United States, the bulk of which are currently landfilled or stockpiled. This consumes valuable landfill space, or, if improperly disposed, creates a fire hazard and provides a prolific breeding ground for rats and mosquitoes. The use of tire shreds as lightweight fill material can sharply reduce the tire disposal problem. The present study, based on laboratory testing and numerical modeling examines the feasibility of incorporating tire s...

  13. Numerical simulation of heat dissipation processes in underground power cable system situated in thermal backfill and buried in a multilayered soil

    International Nuclear Information System (INIS)

    Highlights: • A practical thermal analysis of underground power cable system. • The geological measurements were performed for cable line placement location. • Dry zone formation effect included in soil and FTB thermal conductivity formula. • A simplified FEM model of underground power cable system. • The computational numerical code validation with ANSYS. - Abstract: This paper presents the thermal analysis of the underground transmission line, planned to be installed in one of the Polish power plants. The computations are performed by using the Finite Element Method (FEM) code, developed by the authors. The paper considers a system of three power cables arranged in flat (in-line) formation. The cable line is buried in the multilayered soil. The soil layers characteristic and thermal properties are determined from geological measurements. Different conditions of cable bedding are analyzed including power cables placement in the FTB or direct burial in a mother ground. The cable line burial depth, measured from the ground level, varies from 1 m to 2.5 m. Additionally, to include the effect of dry zones formation on the temperature distribution in cable line and surroundings, soil and FTB thermal conductivities are considered as a temperature-dependent. The proposed approach for determining the temperature-dependent thermal conductivity of soil layers is discussed in detail. The FEM simulation results are also compared with the results of the simulation that consider soil layers as homogeneous materials. Therefore, thermal conductivity is assumed to be constant for each layer. The results obtained by using the FEM code, developed by the authors, are compared with the results of ANSYS simulations, and a good agreement was found

  14. 关于管道沟槽回填处理的体会%On the experience in backfill treatment of pipeline trench

    Institute of Scientific and Technical Information of China (English)

    王峰

    2010-01-01

    通过工程实例,提出管道沟槽回填的方案,阐述了施工中的材料要求、施工方式、检测方法、对回填的质量控制措施,以期指导市政排水管道建设工程,保证施工质量.

  15. Application of a Backfilling Method in Coal Mining to Realise an Ecologically Sensitive “Black Gold†Industry

    OpenAIRE

    Xiaowei Feng; Nong Zhang; Lianyuan Gong; Fei Xue; Xigui Zheng

    2015-01-01

    China, as the largest coal-producing and -consuming country in the world, is highly dependent on its coal industry, or “Black Gold†industry, for the national energy and economy. The consequent environmental crises, however, have persisted for decades, and the most serious effect is surface subsidence induced by underground mining. Underground coal excavation in China has ignored this problem for thousands of years, even though it causes conspicuous damage to the surface ecosystem and cons...

  16. Comparative Study of Segment Backfill Materials and Segment Attitude%管片壁后填充材料与管片姿态对比研究

    Institute of Scientific and Technical Information of China (English)

    陈建斌

    2016-01-01

    以神华神东补连塔煤矿二号辅运平硐工程为基础,在混凝土管片壁后分别填充混凝土、豆粒石、单液浆、双液浆等四种材料后,对管片的沉降和扭转进行了对比研究。结果表明填充材料为混凝土时管片的姿态控制最佳。%Based on the second subsidiary transport adit project of Shenhua Shendong Bulianta coal mine,this paper stud-ies the segment settlement and torsion after the concrete segments are filled with concrete,pea gravel,single-liquid grou-ting,double-liquid grouting respectively.The results show that the controlling of segment attitude is the best when filled by the concrete.

  17. Analysis of Factors Affecting the Compressive Strength of Cemented Backfill%胶结充填体抗压强度的影响因素分析

    Institute of Scientific and Technical Information of China (English)

    杨安国; 周宗红; 张秋华

    2014-01-01

    This paper introduces some factors influencing the compressive strength of cemented filling body, in order to demonstrate that the compressive strength of cemented filling body is affected by cementitious materials, inert material, slurry concentration, material ratio and curing conditions. In addition, this paper also points out some problems in mine cemented filling process and the improvement direction.%本文通过介绍影响胶结充填体抗压强度的若干因素,目的是为了说明胶结充填体抗压强度受到胶凝材料、惰性材料、料浆浓度以及物料配比和养护条件等因素的影响。此外,本文还指出了目前矿山胶结在充填过程中存在的一些问题以及改进的方向。

  18. Reliability Analysis of High Level Backfill Based on Chaotic Optimization%震后房屋评价模型的改进

    Institute of Scientific and Technical Information of China (English)

    王楠楠; 王存睿; 高云莉; 王庆春

    2011-01-01

    科学的评定震后的已损毁建筑对震后房屋处理,城市功能的及时恢复,社会生产稳定、生活秩序的恢复等,具有重要的现实意义.针对传统震后的损毁房屋评价模型的不足,提出了一种震后房屋危险性鉴定的评价模型,结合AHP方法,利用实际中各种因素影响的权重构建了相应的模糊隶属度函数,计算地震损毁房屋的等级.利用真实地震中的房屋数据对该方法进行了测试和分析,实验结果表明该方法是科学、有效的,可以一定程度提高震后房屋鉴定的准确性和合理性.%Scientific assessment of damaged buildings after earthquake is very important to the building processing, the timely restoration of urban functions, stability of social production and living order of restoration. In this paper, after analyzed the traditional evaluation model of the earthquake damaged housing, presents a risk assessment identification model for housing after eart hquake, combined with AHP method, using the actual impact of various factors in the weights of the corresponding construct fuzzy function, calculate the level of earthquake damage to building. In this paper, the real earthquake of building data test this method, experimental results indicate that this method is scientific and effectively, improve the identification accurate and rationality.

  19. 75 FR 31477 - Southern Nuclear Operating Company, et al; Notice of Consideration of Issuance of Amendment to...

    Science.gov (United States)

    2010-06-03

    ... Effects of Backfill Geometry,'' remain valid; backfill material placed over the slopes of the excavation... differential settlements, or liquefaction potential. Because the hydraulic conductivity of EGB material is... SSAR 2.5.2.9.2, ``Study of the Effects of Backfill Geometry,'' remain valid, backfill material...

  20. 石灰浆对膏体充填料浆性能的影响研究%Study on the Influence from Lime Mortar to Property of Backfill Paste Filling Slurry

    Institute of Scientific and Technical Information of China (English)

    黄吉荣; 胡万宏; 容宇

    2010-01-01

    介绍了对现有膏体充填工艺所进行的取消石灰浆作添加剂的可行性实验研究.研究了不同浓度、不同石灰添加量对各龄期单轴抗压强度的影响.认为添加石灰对于提高试块3d强度具有较显著的作用,但28d强度大大降低;石灰添加量为6.4%时,28d强度仅为不添加的50%左右,认为取消石灰作为膏体添加剂具有积极意义.

  1. 无砂大孔混凝土在台背回填中的应用%The Application of the Non-sand-and-Big-Hole Concrete to Road Backfill

    Institute of Scientific and Technical Information of China (English)

    狄宝才; 曲义萍

    2007-01-01

    以西林河大桥为工程背景,对无砂大孔混凝土的配合比进行了设计,对无砂大孔混凝土的密度、强度、透水性等三方面路用性能进行了试验研究,提出了行之有效的施工方案,并对无砂大孔混凝土在台背回填中的综合效益进行了分析.

  2. 金属矿充填开采岩体移动对竖井围岩的变形破坏%Shaft deformation and failure due to rock mass movement induced by underground backfill mining of a metal mine

    Institute of Scientific and Technical Information of China (English)

    赵海军; 马凤山; 徐嘉谟; 张亚民; 郭捷

    2012-01-01

    The vertical shaft plays an important role in underground tunnel mining mines. However, few attempts have been done on the deformation and failure mechanics of shafts suffering from rock mass movement in metallic mines undergoing mining activities. Numerical simulation methods and geomechanical methods are applied in the study of deformation, failure and stability of the line No. 14 ventilating shaft in Jinchuan No. 2 Mine under the conditions of different kinds of mining design. The results show that the shaft is seated in the scope of the depression induced by the underground mining, and the displacement of rock mass keeps increasing. Therefore the underground mining is the main factor for the safety and stability of the shaft. Moreover, whether mining of the rich ore body or combined mining of the rich ore body and lean ore body, the distribution regularities of displacement and stress of the shaft are similar, and the section of the faults is still the vulnerable zone of the shaft in which it influences the size and distribution of the displacement and stress greatly. Consequently, it is the faults which cross the shaft and lead to reactivation due to underground mining are the trigger factor, and the rock mass movement, rupture and fall are the primary form of the shaft deformation and failure mechanism, and this kind of fault effects will be aroused again in the future under the present circumstances of mining.%采用数值模拟和地质力学分析的方法,对甘肃金川二矿区地下开采条件下,#14行风井变形破坏问题进行了研究,研究结果表明:#14行风井位于地下开采引起的岩体移动盆地的拉张区,受岩体移动变形影响剧烈,地下开采已经成为了影响竖井安全稳定的主要因素;无论是富矿开采还是贫矿富矿联合开采,竖井井壁的位移和应力分布规律大体相同,其大小与分布特征受断层影响突出,断层所在的部位仍然是竖井井壁的脆弱部位;地下开采引起的#14行风井的破坏是以穿过井筒的断层出现活化为触发因素,以井壁发生错动、破裂、冒落为主要形式的断层效应的集中体现,这也将成为现阶段生产条件下竖井可能再次发生变形、破坏的模式。

  3. Application of Backfill and Water Shutoff Technology in Annular Space of Freezing Pipe and Quality Control%冻结管环形空间充填堵水技术应用与质量控制

    Institute of Scientific and Technical Information of China (English)

    王楷

    2014-01-01

    大海则矿井区域属于白垩系和侏罗系煤系地层,含水软岩抗压强度较低,煤矿立井采用全深冻结法施工.文章结合工程实际介绍了冻结管环形空间充填堵水技术在西部含水软岩地层中应用的必要性和实施概况.同时,提出了若干项技术措施及性质要点来对实施质量进行控制,保证井筒建设与生产的安全.整个泥浆置换工序实施顺利,达到预期效果.

  4. Field surface backfill grouting and excavation and supporting technology of tunnel shallow unsymmetrial loading sector%隧道浅埋偏压段地表回填注浆及开挖支护施工技术

    Institute of Scientific and Technical Information of China (English)

    杨帆

    2007-01-01

    在六潜高速公路磨子潭1#隧道六安端进口浅埋段施工中,采用浅埋段施工挡土墙、水泥稳定碎石土分层回填及地表注浆加固、顶推套拱进洞、钢管注浆超前支护、预留核心土开挖、围岩量测、注浆加强初期支护、偏压加强衬砌等技术措施.施工证明上述施工技术能够保证偏压、浅埋及软弱围岩隧道施工时确保施工期间及后期安全,取得良好效果.

  5. FCC化学填充材料充填技术在高冒区中的应用%FCC Chemistry Packing Material Backfill Technology in Gao Maoqu Application

    Institute of Scientific and Technical Information of China (English)

    倪国峰

    2010-01-01

    杜儿坪煤矿二采区对生产运输以及行人带来安全隐患,影响巷道的长期使用及整个工程进度,为了保证安全,快速高效防止瓦斯的积聚以及煤层的脱落,决定采用FCC化学填充材料进行填充治理.

  6. Consequences of using crushed crystalline rock as ballast in KBS-3 tunnels instead of rounded quartz particles

    International Nuclear Information System (INIS)

    The basic question has been whether such replacement alters the hydraulic conductivity and compressibility as well as expandability and also if the physical and chemical stabilities are altered. The key factor is the microstructural constitution of the bentonite/ballast mixtures, which is primarily controlled by the grain size distribution of the ballast. The compact ability of backfills with quartz sand (SB) is higher than that of backfills with crushed rock as ballast (RB). The physical stability of RB backfills in terms of piping and erosion resistance will be somewhat lower than that of SB backfills. The chemical stability is practically independent of whether the ballast is pure quartz or rock with K-bearing minerals because the temperature in the backfill will be too low to yield significant smectite to illite conversion in the short heating period. In order to reach the same densities of SB and RB backfills, which turn out to give fairly similar physical properties, the latter backfills need more effective compaction or, alternatively, a higher bentonite content. It is estimated that if the bentonite content in RB backfills is not increased while the density is enhanced to what is achievable, these backfills will serve equally well as SB backfills with the densities implied by the basic KBS-3 concept. 23 refs, 27 figs, 7 tabs

  7. 台湾36英寸海上管线项目中的预开沟、预扫床及回填作业%Pre-trenching, Pre-Sweeping and Backfilling for the 36" Offshore Pipeline Project in Taiwan

    Institute of Scientific and Technical Information of China (English)

    爱德华; 王曦

    2003-01-01

    本文主要讨论耙吸挖泥船在管线开沟工程中的优点.台湾36英寸海上管线项目表明了耙吸船这种特殊类型设备的多用性.在这个项目的三种不同场合下,耙吸挖泥船证明了她的各种能力.首先,耙吸船使用专用深水疏浚设备克服了大水深的困难;其次,未预料到的泥土问题,如泥土回流到新开挖沟槽内的问题;第三是由冲刷现象引起的自由跨度(freespans)问题,都藉由耙吸船使用高压冲水方式得以解决.因而,该耙吸挖泥船使项目避免了因预料不到的问题而必须调用昂贵的专用设备以及大的施工期延误.

  8. Stope Stability Influenced by Underhand-Stoping and Consolidated-Backfilling Sequence of Hexagonal-Drift with FLAC Simulation%下向回采和充填顺序对采场稳定性影响的模拟研究

    Institute of Scientific and Technical Information of China (English)

    李兴国; 赵东寅

    2012-01-01

    The stope of underhand-stoping and consolidated-filling by hexagonal-drift was investigative-object,according to the engineering geo-mechanics date from in-situ test,four different stoping and filling sequences of drift were selected, The stress,displacement and plasticity field of medium around drift were simulated and analyzed with FLAC.the stress-strain rule,geometry-distortion character and structure-load capability of stope tructure-medium influenced by the different stoping-filling sequences was investigated. The analytical results showed that,this stoping-filling sequence was safe,feasible and economical technical,which was the drift in the middle of stope was mined first,advanced to headwall step by step,excavated headwall first and footwall secondly, stoping and filling sublevel, the structure-medium stability of stope was influenced by mining and filling less. The inspection and shoring on the stress-focus position was at wall-rock and bottom-rock of headwall and footwall drift should be strengthened,the intensity index of top-filling-body should be ensured.%以某矿下向六角形进路回采胶结充填采场为研究对象,根据现场实测工程地质力学数据,选取4种不同的进路回采和充填顺序,运用FLAC模拟分析进路周围介质应力场、位移场和塑性区分布,研究采场结构介质应力应变规律、几何变形特征和结构承载性能受不同采充顺序扰动的影响.研究结果表明:采场进路从中间开始回采、逐步向上盘推进,先上盘后下盘、分段回采充填的顺序,使采场结构介质稳定性受采充扰动影响较小,是安全可靠、技术可行、经济合理的.同时应注意加强上下盘进路腰部和底板围岩应力集中区的监控和支护,确保顶板充填体强度指标.

  9. The repair of ground cover of Bolivia-Brazil gas pipeline near Paraguay River crossing, in a swamp soft soil region, using geo synthetics reinforced backfilling; Reparo da cobertura do gasoduto Bolivia-Brasil junto ao Rio Paraguai, em trecho com solo mole, utilizando aterro reforcado com geosinteticos

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Cesar Augusto; Jorge, Kemal Vieira; Bechuate Filho, Pedro [TBG - Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Campo Grande, MS (Brazil). Gerencia Regional Centro Oeste (CRGO); Teixeira, Sidnei H.C. [Geohydrotech Engenharia S.C. Ltda., Braganca Paulista, SP (Brazil)

    2005-07-01

    TBG - Transportadora Gasoduto Bolivia-Brasil S.A, executes routine maintenance works at the Gas Pipeline Right of Way, seeking its integrity. In the wetlands of Pantanal, near the Paraguay river crossing, the organic-alluvial soil was submitted to the process of subsidence. This process, associated with the river water flow erosion, shrank the soil volume and diminished or extinguished the pipeline land cover. The pipeline was exposed to the environment, and submitted to tension stresses and the risk of low cycle fatigue during the floods. The cathodic protection system also had to be evaluated, specially in the drought. To mitigate the problem, the embankment technique was adopted using sandy soil, reinforced with polyester geo-webs and with woven polipropene geo-textiles. The solution also used geo-webs with soil-cement as protection elements against the degradation of the geo-textiles blankets. Some monitoring works are associated with those interventions: monitoring of cathodic protection; topographical verification of horizontal and vertical displacements of the pipeline; levels of land covering, and rainfalls and flood measurement. The base of the embankment was built with hydraulic transported soil, and at the end consistently supported the gas pipeline. (author)

  10. Geochemical assessment of nuclear waste isolation. Report of activities during fiscal year 1982

    International Nuclear Information System (INIS)

    The status of the following investigations is reported: canister/overpack-backfill chemical interactions and mechanisms; backfill and near-field host rock chemical interactions mechanisms; far-field host rock geochemical interactions; verification and improvement of predictive algorithms for radionuclide migration; and geologic systems as analogues for long-term radioactive waste isolation

  11. 30 CFR 917.12 - State regulatory program and proposed program amendment provisions not approved.

    Science.gov (United States)

    2010-07-01

    ... completely incised or created by a depression left by backfilling and grading but not meeting MSHA requirements at 30 CFR 77.216 or not meeting the Class B and C classifications at section 1(10)(b) is not... depression left by backfilling and grading, that is not a sedimentation pond or coal mine waste...

  12. Geochemical assessment of nuclear waste isolation. Report of activities during fiscal year 1982

    Energy Technology Data Exchange (ETDEWEB)

    1983-07-01

    The status of the following investigations is reported: canister/overpack-backfill chemical interactions and mechanisms; backfill and near-field host rock chemical interactions mechanisms; far-field host rock geochemical interactions; verification and improvement of predictive algorithms for radionuclide migration; and geologic systems as analogues for long-term radioactive waste isolation.

  13. Migration and diffusion of radionuclides in engineered barrier system

    International Nuclear Information System (INIS)

    This paper describes the present status of the multibarrier system performance tests to provide a preliminary assessment of nuclide migration in the engineered barriers for shallow land burial of the low-level radioactive waste. Migration of radionuclides with seeped water through backfill and in subsequent diffusion in concrete pit are considered in this study. The results of laboratory investigations of unsaturated flow in backfill and radionuclides migration / diffusion in engineered barrier system are described and the calculated distribution of the radionuclides in backfill is presented

  14. Loviisa Power Station - final disposal of reactor waste

    International Nuclear Information System (INIS)

    This report is based on the earlier published results of research into the properties and function of the candidate backfill materials. The results of the backfill material research, and the sealing concepts presented in the literature have been evaluatedand applied to sealing the Loviisa Reactor Waste Repository taking into consideration the local rock and groundwater conditions. It is emphasised that the applicability of the presented backfill materials and plugs to repository sealing must still be carefully evaluated on the basis of detailed studies and the local environment. 24 refs

  15. Bulkhead pressure measurements in model fill pours

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R.J.; Roettger, J.J.

    1984-08-01

    The results of a series of model stope pours designed to investigate working pressures on bulkheads during hydraulic pouring of classified tailings backfill are reported. Total bulkhead pressures and fill water pressures were monitored under the condition of a fully saturated backfill. Similitude of the model testing is discussed and equations are developed to estimate bulkhead pressures under prototype conditions. The model results show that good base drainage, combined with a bulkhead setback, can reduce the expected bulkhead pressures to values such that timber or concrete block structures should be capable of supporting a saturated backfill.

  16. Ring exciting thin layer method applied to the forced vibration test of the Hualien large scale soil-structure interactions (SSI) model

    International Nuclear Information System (INIS)

    The blind prediction and post-test correlation analyses are conducted on the forced vibration tests of the 1/4 scale reinforced concrete cylindrical containment model both before and after backfill. In the present paper described for the case after backfill, the ring exciting thin layer technique was introduced to account realistically for the axisymmetrical irregularity of the soil condition due to the backfill. The computed results demonstrated that the proposed method has a great potential for simulating the dynamic responses of the soil-structure system to the forced vibration. (author). 5 refs., 8 figs

  17. Clay modified crushed salt for shaft sealing elements. Material optimization and evaluation in field tests

    Energy Technology Data Exchange (ETDEWEB)

    Glaubach, Uwe; Hofmann, Martin; Gruner, Matthias; Kudla, Wolfram [TU Bergakademie Freiberg (Germany). Inst. of Mining and Special Civil Engineering

    2015-07-01

    Salt-based materials are intended to use for backfill and sealing systems in geotechnical barriers in underground HLW-repositories. Due to the creep of the saliniferous host rock, the salt backfill will be compacted during several hundreds or thousands years of operation to a minimum of porosity resp. permeability. To raise the sealing potential of a salt-based backfill, the porosity after construction should be minimized by optimal material performance and compaction performance. A procedure to optimize the grain size distribution of crushed salt and its water and clay content is described. The optimized salt fraction gets a better compaction behavior than straight mine-run salt. The addition of a filler-like material (e.g. Friedland Clay Powder) reduces the total porosity and permeability. Backfill columns made from crushed salt and clay probably include an instant sealing function.

  18. Cumulative releases of radionuclides from uncontained waste packages

    International Nuclear Information System (INIS)

    This report describes mathematical predictions for the migration of radionuclides from an emplaced radioactive waste container. The model assumes a spherical-equivalent waste solid surrounded by backfill but neglects the effect of decay heat. 7 refs., 2 tabs

  19. Pervious Pavement System Evaluation- Abstract

    Science.gov (United States)

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, gra...

  20. Pervious Pavement System Evaluation- Abstract 1

    Science.gov (United States)

    Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, gra...

  1. Evaluation of low-pH cement degradation in tunnel plugs and bottom plate systems in the frame of SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    Grandia, Fidel; Galindez, Juan-Manuel; Molinero, Jorge; Arcos, David (Amphos XXI Consulting S.L., Barcelona (Spain))

    2010-09-15

    Low-pH concrete plugs are going to be used during the backfilling of depositional tunnels of the high-level nuclear waste repository. The stability of these plugs, however, is thought to be affected by water-concrete interaction that may lead to cement degradation and dissolution. Alkaline plumes derived from such a degradation could jeopardize the chemical stability of the clay material in the backfill due to the enhanced dissolution kinetics under high-pH solutions. In this study, the cement durability of concrete plugs to be used in the repository is numerically evaluated by performing reactive transport simulations based on the geochemical degradation of the cement compounds, mainly calcium silicate hydrates (CSH). The implementation of degradation process into the geochemical model is based on a solid solution approach for CSH alteration. The numerical model also takes into account the dependency of transport properties (e.g. molecular diffusion coefficient) with the changes in porosity due to mineral precipitation-dissolution. The simulations predict that the effect of low-pH concrete alteration on the stability of backfill materials would be low. The main process governing geochemistry in the backfill-concrete boundary would be the quick loss of porosity due to ettringite precipitation. The very high molar volume of this mineral enhances the rate of clogging. The ettringite formation is mainly driven by the high sulphate concentration in the backfill porewater, which in turn is controlled by the equilibrium with gypsum in the backfill. The release and diffusion of calcium (from CSH replacement) and Al (from katoite dissolution) from concrete causes ettringite precipitation at the concrete-backfill boundary. The loss of porosity dramatically reduces solute diffusion and, consequently, the backfill-concrete system remains almost invariably for hundreds of years

  2. Study on forced vibration tests for large scale SSI model. Test results and their analysis

    International Nuclear Information System (INIS)

    A Large-Scale Seismic Test (LSST) Program has been conducted at Hualien, Taiwan, to obtain earthquake-induced soil-structure interaction (SSI) data in a stiff soil site environment. Forced vibration tests of the Hualien 1/4-scale containment SSI test model were conducted in October, 1992 before backfill (without embedment) and in February, 1993 after backfill (with embedment) for the purpose of defining basic dynamic characteristics of the soil-structure system. As results, peak frequencies were obtained as 4.1 and 4.3 Hz with twin peaks for both NS and EW horizontal excitation before backfill and as 6.1 and 6.3 Hz for NS and EW excitation respectively after backfill and orthogonal components were rather large. This results suggested existence of principal axes which were different from excitation directions. They were estimated 34 degree before backfill and 30 degree after backfill counterclockwise from NS direction, respectively. After transformed to the principal axes, each resonance curve had single peak and the orthogonal component became negligible. Based on this transformed results, the basic dynamic characteristics of the soil-structure system were obtained, namely, natural frequencies and damping factors. Soil impedances were also obtained by the method minimizing error function defined newly. (author)

  3. Behavior of crushed salt under heat source in boreholes in a salt mine (Amelie Mine, Alsace Potash Mines, France)

    International Nuclear Information System (INIS)

    The study of thermomechanical interaction between rock salt and crushed salt, used as a backfilling material at the final stage of radioactive waste disposal in salt formations, led to perform an in situ test at the Amelie Mine(The Alsace Potash Mines in France). The field tests site is located at a depth of 520m and the tests were performed in six parallel boreholes. Five boreholes were backfilled using three types of crushed salt, changing by their grain size (fine = 0.4 mm; natural = 1 mm; coarse = 2 mm). The sixth borehole was not backfilled in order to witness for rock salt behavior without backfilling confinement. Except the first borehole used as a pilot test, the four backfilled boreholes were heated during four months with two levels of heat output (1.6 kW, then 2.2 kW). Cooling was also followed during four months after heating interruption. The maximum of temperature obtained on the wall of the backfilled boreholes was about 1000C during the first field test and 1300C during the second. The thermal diffusivity of rock mass and the coefficient of heat exchange by convection are studied. In spite of the case that the crushed salt thermal conductivity is initially ten times less than of rock salt, no excessive temperature concentration was obtained on the heat sources

  4. Tests for evaluation of pellets as foundation bed material KBP1003 - ASKAR

    International Nuclear Information System (INIS)

    The reference design for the backfill of deposition tunnels, described in SKB (2010), include bentonite blocks, bentonite pellets and a foundation bed of bentonite pellets or granulate. The tunnel floor needs to be flat and have sufficient bearing capacity to make it possible to stack the backfill blocks according to the reference design. To achieve a flat foundation the tunnel floor will be covered with a bed of pellets or granulate made of bentonite clay. The bed can be either compacted or non compacted. Bed tests have been performed as a part of the project KBP1003 DP1 Design, which is a subproject of KBP1003 ASKAR. The main objectives for KBP1003 DP1 is to define all requirements for the backfill and its production and installation prior to start of the large scale tests, based on given perquisites. KBP1003 is based on the reference design for the backfill of deposition tunnels which was developed in 2010 (SKB 2010). The concept for installation and block design has been further developed during the project. A new dimension of the backfill blocks has been developed; the chosen dimension makes it possible to gain overlapping joints between the blocks by block stacking. The further developed concept is hereinafter referred to as the ASKAR-concept. The purpose of the performed bed tests was to define the bed requirements in the backfill installation to enable stable stacking of backfill blocks. The tests included stacking of blocks on different bed materials, on blasted and wire sawn floor, with and without concurrent water inflow. The bed tests was subdivided into four main parts: - block stacking on different bed compositions - block stacking on bed during water inflow - block stacking in a realistic test tunnel - block stacking on the upper part of the deposition hole and bevel

  5. Tests for evaluation of pellets as foundation bed material KBP1003 - ASKAR

    Energy Technology Data Exchange (ETDEWEB)

    Johnsson, Anna (ES-Konsult AB (Sweden))

    2011-12-15

    The reference design for the backfill of deposition tunnels, described in SKB (2010), include bentonite blocks, bentonite pellets and a foundation bed of bentonite pellets or granulate. The tunnel floor needs to be flat and have sufficient bearing capacity to make it possible to stack the backfill blocks according to the reference design. To achieve a flat foundation the tunnel floor will be covered with a bed of pellets or granulate made of bentonite clay. The bed can be either compacted or non compacted. Bed tests have been performed as a part of the project KBP1003 DP1 Design, which is a subproject of KBP1003 ASKAR. The main objectives for KBP1003 DP1 is to define all requirements for the backfill and its production and installation prior to start of the large scale tests, based on given perquisites. KBP1003 is based on the reference design for the backfill of deposition tunnels which was developed in 2010 (SKB 2010). The concept for installation and block design has been further developed during the project. A new dimension of the backfill blocks has been developed; the chosen dimension makes it possible to gain overlapping joints between the blocks by block stacking. The further developed concept is hereinafter referred to as the ASKAR-concept. The purpose of the performed bed tests was to define the bed requirements in the backfill installation to enable stable stacking of backfill blocks. The tests included stacking of blocks on different bed materials, on blasted and wire sawn floor, with and without concurrent water inflow. The bed tests was subdivided into four main parts: - block stacking on different bed compositions - block stacking on bed during water inflow - block stacking in a realistic test tunnel - block stacking on the upper part of the deposition hole and bevel

  6. Preliminary conceptual designs for advanced packages for the geologic disposal of spent fuel

    International Nuclear Information System (INIS)

    The present study assumes that the spent fuel will be disposed of in mined repositories in continental geologic formations, and that the post-emplacement control of the radioactive species will be accomplished independently by both the natural barrier, i.e., the geosphere, and the engineered barrier system, i.e., the package components consisting of the stabilizer, the canister, and the overpack; and the barrier components external to the package consisting of the hole sleeve and the backfill medium. The present document provides an overview of the nature of the spent fuel waste; the general approach to waste containment, using the defense-in-depth philosophy; material options, both metallic and nonmetallic, for the components of the engineered barrier system; a set of strawman criteria to guide the development of package/engineered barrier systems; and four preliminary concepts representing differing approaches to the solution of the containment problem. These concepts use: a corrosion-resistant meta canister in a special backfill (2 barriers); a mild steel canister in a corrosion-resistant metallic or nonmetallic hole sleeve, surrounded by a special backfill (2 barriers); a corrosion-resistant canister and a corrosion-resistant overpack (or hole sleeve) in a special backfill (3 barriers); and a mild steel canister in a massive corrosion-resistant bore sleeve surrounded by a polymer layer and a special backfill (3 barriers). The lack of definitive performance requirements makes it impossible to evaluate these concepts on a functional basis at the present time

  7. Movement and deformation laws of the overlying strata in paste filling stope

    Institute of Scientific and Technical Information of China (English)

    Xu Ying; Chang Qingliang; Zhou Huaqiang; Cao Zhong; Li Xiushan; ChenJianhang

    2011-01-01

    We combined the similar simulation with numerical simulation to analyze the movement and deformation features of overlying strata caused by paste backfill mining,study the movement and deformation laws of the overlying strata in paste backfill mining,structural movement of the stope strata as well as the stope stress distribution laws.Furthermore,authors also explored the key factors to the movement and deformation of the overlying strata in paste backfill mining.The results indicate that a caving zone existed in the bending zone only in the overlying strata of the paste backfill mining.Compared with the roof caving mining,the degree of stress concentration and area of influence in the paste filling stope were apparently smaller.And the degree of destruction and area of the overlying strata decreased prominently.Also,there was no apparent strata behavior in the working face.Lastly,the filling ratio was the key to control the movement and deformation of the overlying strata.Combined with a specific engineering example,the author proved the reliability of the simulation results and provided a theoretical basis for the further extension of the paste backfill mining.

  8. Neon as a Buffer Gas for a Mercury-Ion Clock

    Science.gov (United States)

    Prestage, John; Chung, Sang

    2008-01-01

    A developmental miniature mercury-ion clock has stability comparable to that of a hydrogen-maser clock. The ion-handling components are housed in a sealed vacuum tube, wherein a getter pump is used to maintain the partial vacuum, and the evacuated tube is backfilled with mercury vapor in a buffer gas. Neon was determined to be the best choice for the buffer gas: The pressure-induced frequency pulling by neon was found to be only about two-fifths of that of helium. Furthermore, because neon diffuses through solids much more slowly than does helium, the operational lifetime of a tube backfilled with neon could be considerably longer than that of a tube backfilled with helium.

  9. Real-time gamma imaging of technetium transport through natural and engineered porous materials for radioactive waste disposal.

    Science.gov (United States)

    Corkhill, Claire L; Bridge, Jonathan W; Chen, Xiaohui C; Hillel, Phil; Thornton, Steve F; Romero-Gonzalez, Maria E; Banwart, Steven A; Hyatt, Neil C

    2013-12-01

    We present a novel methodology for determining the transport of technetium-99m, a γ-emitting metastable isomer of (99)Tc, through quartz sand and porous media relevant to the disposal of nuclear waste in a geological disposal facility (GDF). Quartz sand is utilized as a model medium, and the applicability of the methodology to determine radionuclide transport in engineered backfill cement is explored using the UK GDF candidate backfill cement, Nirex Reference Vault Backfill (NRVB), in a model system. Two-dimensional distributions in (99m)Tc activity were collected at millimeter-resolution using decay-corrected gamma camera images. Pulse-inputs of ~20 MBq (99m)Tc were introduced into short (disposal of nuclear waste and potentially to a wide variety of other subsurface environments.

  10. A disposal centre for irradiated nuclear fuel: conceptual design study

    International Nuclear Information System (INIS)

    This report describes a conceptual design of a disposal centre for irradiated nuclear fuel. The surface facilities consist of plants for the preparation of steel cylinders containing irradiated nuclear fuel immobilized in lead, shaft headframe buildings, and all necessary support facilities. The undergound disposal vault is located on one level at a depth of 1000 metres. The cylinders containing the irradiated fuel are emplaced on a one-metre thick layer of backfill material and then completely covered with backfill. All surface and subsurface facilities are described, operations and schedules are summarized, and cost estimates and manpower requirements are given. (auth)

  11. Direct methods of soil-structure interaction analysis for earthquake loadings

    Energy Technology Data Exchange (ETDEWEB)

    Yun, J. B.; Kim, J. M.; Kim, Y. S. and others [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1993-07-15

    The objectives of this study are to review the methods of soil- structure interaction system analysis, particularly the direct method, and to carry out the blind prediction analysis of the Forced Vibration Test(FVT) before backfill in the course of Hualien LSST project. The scope and contents of this study are as follows : theoretical review on soil-structure interaction analysis methods, free-field response analysis methods, modelling methods of unbounded exterior region, hualien LSST FVT blind prediction analysis before backfill. The analysis results are found to be very well compared with the field test results.

  12. Development of Multiple Cement Mixture and Its Applied Technology

    Science.gov (United States)

    Sun, Jie; Li, Qiaoling; Liu, Feng; Liu, Shipeng

    Currently, materials used to backfill grooves in municipal pipeline projects are pure soil and lime earth generally. Besides, punning or rolling compaction is used. Thus, it is difficult to compact or tamp haunches under pipes. Because of immersion of surface water and activities of underground water and as water inside pipes or underground structures leaks outward, fine-grained soil in backfill move with activities of underground water and collapse is caused for ground. This thesis mainly introduces multiple cement mixture and its performance.

  13. Feasibility and economic consequences of retrievable storage of radioactive waste in the deep underground

    International Nuclear Information System (INIS)

    The economic consequences of retrievable storage have been investigated by comparing two extreme options of retrievable storage. In one option the storage facility is kept in operation, using minimal backfill of the storage galleries. In the other option the storage facility is completely backfilled, sealed and abandoned. In the second option construction of a new mine will be necessary in case of retrieval. The point in time has been determined when the second option will be cheapter than the first. This has been done for clary, granite and rocksalt as host formation, and both for vitrified waste and spent fuel. (orig.)

  14. Soil density and mass attenuation coefficients for use in shielding calculations at the Hanford Waste Vitrification Plant

    International Nuclear Information System (INIS)

    Compacted, backfilled soil excavated during construction may be used to provide shielding from gamma radiation at the Hanford Waste Vitrification Plant (HWVP). To provide a reasonable estimate of the shielding offered by this backfilled soil, the bulk density and the composition of the emplaced soil must be specified. This study provides an estimate of the bulk density and the mass attenuation coefficients of soil used for calculating gamma-ray shielding attenuation at the HWVP. These estimates are based on measurements taken from soil samples and underlying rock samples at the Hanford Site

  15. Surface-immobilized pyridine-functionalized gamma-cyclodextrin: alkanethiol co-adsorption-induced reorientation.

    Science.gov (United States)

    Mallon, Colm T; Forster, Robert J; McNally, Andrea; Campagnoli, Elena; Pikramenou, Zoe; Keyes, Tia E

    2007-06-19

    Monolayers of di-6A,6B-deoxy-6-(4-pyridylmethyl)amino-gamma-cyclodextrin (gamma-CD-(py)2) have been formed on polycrystalline platinum electrodes and investigated using electrochemical and surface-enhanced Raman spectroscopy (SERS). The behavior of self-assembled monolayers of (gamma-CD-(py)2) alone, (gamma-CD-(py)2) backfilled with 1-nonanethiol, and 1-nonanethiol are reported. The potential dependence of the capacitance indicates that the film capacitance is higher for the backfilled CD layers than for 1-nonanethiol layers, most likely due to ion flux through the CD cavity. SERS spectra of the backfilled layer exhibit features associated with both pyridine-functionalized CD and alkane moieties. Investigations using [Fe(CN)6]4- as a solution-phase probe indicate that the backfilled CD-alkane thiol layer exhibits enhanced blocking properties compared to gamma-CD-(py)2 films alone. Complete blocking was achieved by a combination of backfilling and insertion of a high-affinity guest 1-adamantylamine into the cavity. Significantly, an electroactive guest with high affinity for gamma-CD, [Co(biptpy)2]2+, does not exhibit a redox response at the gamma-CD-(py)2 layer but molecular recognition is turned on by backfilling the CD layer with 1-nonanethiol molecules. This switching on of the electrochemical activity suggests that the CD hosts are initially inaccessible but reorientate upon backfilling, exposing the CD opening to solution and permitting a supramolecular host-guest complex to form. The binding of [Co(biptpy)2]2+ to gamma-CD in the backfilled monolayer depends on the bulk concentration of guest and is modeled by the Langmuir isotherm, yielding an association constant for the Co2+ state of 1.45 +/- 0.46 x 105 M-1 and a limiting surface coverage 1.49 +/- 0.25 x 10-11 mol cm-2. The surface coverage of the divalent state is higher than the trivalent state, reflecting the dynamic nature of the inclusion. PMID:17521206

  16. Impact assessment of shallow land burial for low-level waste: modelling of the water flow and transport of radionuclides in the near-field

    Energy Technology Data Exchange (ETDEWEB)

    Walravens, J.; Volckaert, G.

    1996-09-18

    The Belgian concept for disposal of low-level waste consists of storage of waste drums into a concrete vault backfilled with a cementitious grout. The vault is placed above the water table and will be covered with a multilayer cap of clay, gravel, and sandy materials. The SCK/CEN is charged with the long-term performance assessment of the disposal site. The main processes and parameters determining the radioactivity release from the site are identified. The principal processes are the infiltration through the top cover and the sorption of waste on the backfill. The release of radionuclides from the site was modelled with the PORFLOW numerical code.

  17. Rock segments for reducing the amount of cement used on high-level radioactive waste disposal

    International Nuclear Information System (INIS)

    Methods for constructing tunnels using the minimum quantities of cement-type support materials in high-level radioactive waste disposal facilities have been developed. Research and development concerning the technical aspects of the formation of rock segments using low alkali mortar have been conducted. This study examined the mechanical characteristics of rock segments and backfill materials and analyzed the stability of the drift that is supported by the rock segments and gravel backfill. The results confirmed the technical aspects of the formation of the rock segments and the effectiveness of the planned efforts to further reduce the amount of cement used. (author)

  18. Development of rock segment for reduction of amount of cement use

    International Nuclear Information System (INIS)

    The authors have been developing methods for constructing tunnels using the minimum quantities of cement-type support materials in high-level radioactive waste disposal facilities and advancing research and development about the technical formation of rock segment using low alkali mortar. In this study, the mechanical characteristic values concerning the rock segment and backfill materials were examined. The stability analysis of drift supported by the rock segment and backfilling with gravel were performed. Technical formation and effectiveness of the support planned for further reduction in cement influence was confirmed from the study result. (author)

  19. A review of recent advances in numerical modelling of local scour problems

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu

    2014-01-01

    A review is presented of recent advances in numerical modelling of local scour problems. The review is organized in five sections: Highlights of numerical modelling of local scour; Influence of turbulence on scour; Backfilling of scour holes; Scour around complex structures; and Scour protection...

  20. Physical and numerical modelling of earth pressure on anchored sheet pile walls in sand

    DEFF Research Database (Denmark)

    Krogsbøll, Anette Susanne; Fuglsang, Leif D

    2006-01-01

    The influence of wall flexibility on earth pressure, bending moments and failure modes is studied. Numerical models are compared to results from model tests carried out in a geotechnical centrifuge. The back-fill is dry sand and failure is introduced by allowing the wall to rotate around the anch...

  1. Tracking Trends: Students' Information Use in the Social Sciences and Humanities, 1995-2008

    Science.gov (United States)

    Smyth, Joanne B.

    2011-01-01

    This study uses citation analysis to examine students' dissertations and theses in history, psychology, and education, noting changes in research practices since the introduction of electronic journals and other online sources. Some findings challenge earlier studies, showing that students are making greater use of journal backfiles and that this…

  2. A Reality Check on Hedge Funds Returns

    NARCIS (Netherlands)

    Sluis, van der Pieter Jelle; Posthuma, Nolke

    2003-01-01

    In this article we examine the backfill bias or instant history bias for hedge funds using additional information from the Tass database. This is information about the exact date a hedge fund starts to reporting to Tass. Using this information we are able to reveal the length of the instant historie

  3. Selenium mobilization in a surface coal mine, Powder River Basin, Wyoming, U.S.A.

    Science.gov (United States)

    Dreher, G.B.; Finkelman, R.B.

    1992-01-01

    Elevated concentrations (0.6-0.9 mg/l) of selenium were detected in the groundwater of a small backfill area at a surface mine in the Powder River Basin, Wyoming. This report focuses on the source of selenium, its modes of occurrence in overburden deposits and backfill groundwater, and its fate. The immediate source of the selenium appeared to be the dissolution of preexisting soluble salts from the unsaturated zone of the overburden. The ultimate source of selenium was probably the oxidation of selenium-bearing pyrite in the geologic past. Overburden was placed partially in the saturated zone of the backfill where, upon resaturation, soluble salts dissolved in the groundwater. Water standing in the pit at the time of backfilling might have contributed to the elevated concentrations of selenium and other solutes. Selenium was found in an ash-rich coal and in clastic sediments in seven different modes of occurrence. The concentration of soluble selenium in the groundwater at this site has been decreasing since monitoring began in late 1982, and at the present rate of decrease, the concentration should drop below the State of Wyoming guideline of 0.05 mg/l for selenium in water intended for use by livestock by about mid-1992. The decrease in soluble selenium concentration may in part be due to microbially assisted reduction of selenate followed by sorption on clays and other sorbents. ?? 1992 Springer-Verlag New York Inc.

  4. THERMALLY CONDUCTIVE CEMENTITIOUS GROUTS FOR GEOTHERMAL HEAT PUMPS. PROGRESS REPORT BY 1998

    Energy Technology Data Exchange (ETDEWEB)

    ALLAN,M.L.; PHILIPPACOPOULOS,A.J.

    1998-11-01

    Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98.

  5. Evaluation of radionuclides migration in environment

    International Nuclear Information System (INIS)

    Radioactive waste management is one of the most pressing problems facing the world today because of its long half-life and the transport of radionuclides to the environment. The migration of radionuclides in environment is affected by its sorption in backfill materials, water pore velocity, water flowing direction, dispersion of radionuclides, components of backfill materials, species of radionuclides, microorganism effect and complexation ability of organic substances etc. In this study, the distribution coefficient of Eu(III) derived from batch experiments is used to evaluate the migration behavior of Eu(III) in compacted bentonite after long time. The effect of the dispersion coefficient and the pore water velocity on the migration of Eu(III)is also calculated. It is found that the variation of the distribution coefficient and water velocity has an obviously effect on the migration of Eu(III) in backfill materials and 30 m of the backfill materials is sufficient to prevent the migration of Eu(III) in environment. The dispersion coefficient has little effect on the migration of Eu(III). The evaluated results are applicable to estimate the escape of radionuclides from buried radioactive waste to the environment. (authors)

  6. Conference summaries

    International Nuclear Information System (INIS)

    This volume contains conference summaries of the international conference on radioactive waste management of the Canadian Nuclear Society. Topics of discussion include: storage and disposal; hydrogeology and geochemistry; transportation; buffers and backfill; public attitudes; tailings; site investigations and geomechanics; concrete; economics; licensing; matrix materials and container design; durability of fuel; biosphere modelling; radioactive waste processing; and, future options

  7. Field Measurements and Pullout Tests of Reinforced Earth Retaining Wall

    Institute of Scientific and Technical Information of China (English)

    陈群; 何昌荣; 朱分清

    2004-01-01

    In this paper, field measurements and pullout tests of a new type of reinforced earth retaining wall, which is reinforced by trapezoid concrete blocks connected by steel bar, are described. Field measurements included settlements of the earth fill, tensile forces in the ties and earth pressures on the facing panels during the construction and at completion. Based on the measurements, the following statements can be made: ( 1 ) the tensile forces in the ties increased with the height of backfill above the tie and there is a tensile force crest in most ties; (2) at completion, the measured earth pressures along the wall face were between the values of the active earth pressures and the pressures at rest; (3) larger settlements occurred near the face of the wall where a zone of drainage sand and gravel was not compacted properly and smaller settlements occurred in the well-compacted backfill. The results of field pullout tests indicated that the magnitudes of pullout resistances as well as tensile forces induced in the ties were strongly influenced by the relative displacements between the ties and the backfill, and pullout resistances increased with the height of backfill above the ties and the length of ties.

  8. Plutonium Immobilization Can Loading Preliminary Specifications

    Energy Technology Data Exchange (ETDEWEB)

    Kriikku, E.

    1998-11-25

    This report discusses the Plutonium Immobilization can loading preliminary equipment specifications and includes a process block diagram, process description, equipment list, preliminary equipment specifications, plan and elevation sketches, and some commercial catalogs. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.

  9. 75 FR 39284 - Southern Nuclear Operating Company et al.; Notice of Availability of Environmental Assessment and...

    Science.gov (United States)

    2010-07-08

    ... COMMISSION Southern Nuclear Operating Company et al.; Notice of Availability of Environmental Assessment and... Spicher, Project Manager, AP1000 Branch 1, Division of New Reactors Licensing, Office of New Reactors, U.S... engineered granular backfill (EGB). NRC has prepared an Environmental Assessment (EA) in support of...

  10. Stress field evolution law of mining environment reconstructing structure with change of filling height

    Institute of Scientific and Technical Information of China (English)

    CHEN Qing-fa; ZHOU Ke-ping; WANG Li-li

    2010-01-01

    For improving global stability of mining environment reconstructing structure,the stress field evolution law of the structure with the filling height change of low-grade backfill was studied by ADINA finite element analysis code.Three kinds of filling schemes were designed and calculated,in which the filling heights were 2,4,and 7 m,separately.The results show that there are some rules in the stress field with the increase of the filling height as follows:(1)the maximum value of tension stress of the roof decreases gradually,and stress conditions are improved gradually;(2)the tension stress status in the vertical pillar is transformed into the compressive stress status,and the carrying capacity is improved gradually; however,when the filling height is beyond 2.8 m,the carrying capacity of the vertical pillar grows very slowly,so,there is little significance to continue to fill the low-grade backfill;(3)the bottom pillar suffers the squeezing action from the vertical pillars at first and then the gravity action of the low-grade backfill,and the maximum value of tension stress of the bottom pillar firstly increases and then decreases.Considering the economic factor,security and other factors,the low-grade backfill has the most reasonable height(2.8 m)in the scope of all filling height.

  11. Stability of submerged rock berms exposed to motion of liquefied soil in waves

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Dixen, Figen Hatipoglu; Fredsøe, Jørgen

    2011-01-01

    The paper describes the results of an experimental study on the behaviour of a submerged rock berm in liquefied backfill soil. The soil is liquefied by waves, and the rock berm is subject to the orbital motion of the liquefied soil. The soil used in the experiments was silt with d50=0.075mm. Vari...

  12. 40 CFR 144.26 - Inventory requirements.

    Science.gov (United States)

    2010-07-01

    ... other backfill wells ; (B) Radioactive waste disposal wells that are not Class I wells (40 CFR 146.5 (e)(11)) (C) Geothermal energy recovery wells ; (D) Brine return flow wells ; (E) Wells used in... administered programs the information need not be submitted if a complete permit application is...

  13. Visualization of microscale phase displacement proceses in retention and outflow experiments: nonuniquensess of unsaturated flow properties

    DEFF Research Database (Denmark)

    Mortensen, Annette Pia; Glass, R.J.; Hollenbeck, K.J.;

    2001-01-01

    we observe the drainage process to be composed of a mixture of fast air fingering and slower air back-filling. The influence of each of these microscale processes is controlled by a combination of the size and the speed of the applied boundary step, the initial saturation and its structure, and small...

  14. Rational design and construction of temporary steel tower bases; Karitetto kiso sekkei seko no gorika ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Ikemoto, M. [Kansai Electric Power Co. Inc., Osaka (Japan)

    2000-01-10

    Current design and construction of temporary steel tower bases are equivalent to those for permanent facilities, and removal of the whole base concrete requires a great deal of labor and cost. The newly developed rational liner plate type base uses no concrete, and uses liner plates in place of adhesive and frictional parts of previous base floor plates. The workability of back-filling using sandbags is very excellent. Use of improved soil material as back-filling mortar of liner plates shows a favorable separability. The whole base is reusable because of no damage of each component member. Unlike concrete bases, the liner plate base produces no waste materials due to removal. The steel-base anchor type base can reduce both excavating and back-filling soil by using earth anchors, and reduce excavating soil as much as possible by allotting lifting force to each earth anchor. Reduction of both excavating and back-filling soil makes the removing work of bases simple. Cost reduction of 30-40% was attained by each newly developed base as compared with costs of conventional bases. (NEDO)

  15. 10 CFR 50.10 - License required; limited work authorization.

    Science.gov (United States)

    2010-01-01

    ... Commission requirements in 10 CFR Chapter I applicable to the design of those portions of the facility within... storage sheds, warehouse and shop facilities, utilities, concrete mixing plants, docking and unloading... construction are the driving of piles, subsurface preparation, placement of backfill, concrete, or...

  16. SES and Acoustics at GSFC

    Science.gov (United States)

    Hogue, Patrick

    2008-01-01

    This paper presents air and surface cleanliness characterization of the acoustics test facility and large (SES) thermal vacuum chamber at Goddard Space flight Center in Greenbelt, MD during the New Horizons Pluto probe program. It is shown that slow back-fill of the SES chamber is necessary to prevent excessive particle redistribution.

  17. JSTOR: A Non-Profit Working To Redefine Access to the Scholarly Journal.

    Science.gov (United States)

    Chepesiuk, Ron

    1997-01-01

    As costs of subscriptions to scholarly journals rise, libraries struggle to house their collections. Journal Storage (JSTOR) is building a reliable and comprehensive archive of important literature, filling the gaps in existing collections of backfiles, fostering preservation, increasing access, finding ways to reduce storage and care costs, and…

  18. Digital Format for Depositary Part of Scientific Publications' Collection

    Science.gov (United States)

    Zemskov, Andrei; Evstigneeva, Galina

    As a rule, any large library has so called depositary part of collection. Specific circulation of these publications is not high, but preservation, conservation and provision of access to given collection need permanent efforts. The paper presents evaluation of expenses and centralized systems efficiency. These systems (e.g. JSTOR, Backfiles for Future) are publicly accessible collections of full text versions of scientific periodicals.

  19. The Practicalities of Document Conversion.

    Science.gov (United States)

    Galbraith, Ian

    1993-01-01

    Describes steps involved in the conversion of source documents to scanned digital image format. Topics addressed include document preparation, including photographs and oversized material; indexing procedures, including automatic indexing possibilities; scanning documents, including resolution and throughput; quality control; backfile conversion;…

  20. Joining of beryllium by braze welding technique: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Banaim, P.; Abramov, E. [Ben-Gurion Univ. of the Negev, Beersheba (Israel); Zalkind, S.; Eden, S.

    1998-01-01

    Within the framework of some applications, there is a need to join beryllium parts to each other. Gas Tungsten Arc Braze Welds were made in beryllium using 0.3 mm commercially Aluminum (1100) shim preplaced at the joint. The welds exhibited a tendency to form microcracks in the Fusion Zone and Heat Affected Zone. All the microcracks were backfilled with Aluminum. (author)

  1. Modelling approach for geochemical changes in the Prototype repository engineered barrier system

    International Nuclear Information System (INIS)

    The study deals with a full-scale test of a repository concept for nuclear waste. The work is motivated and targeted to the safety assessment of a final repository for highly active nuclear waste. Successive rounds of predictive modelling are confidence building steps if modelling results can be successfully compared to gradually growing up measured test data. Calculations consider geochemical changes during the wetting of repository tunnel backfill and canister buffer, and the time-dependent changes at the boundaries of a repository engineered barrier system (EBS). The backfill and buffer volumes are divided to uniform subsequent reaction cells. The modelling assumes only schematic coupling between geochemical reactions and hydrologic transport. During a wetting front advance, instant water saturation occurs in subsequent, initially undersaturated, cell volumes. However, a water parcel introduced into a cell is expected to stay within that cell until dissolved components, and solid phases are fully equilibrated. The approach concentrates on the major element compositions of porewaters, and the changes in solid phases of the repository. The initial properties of canister buffer resemble the estimations for compacted Wyoming MX-80 sodium bentonite. The tunnel backfill is assumed to consist of sodium bentonite (30%), and crushed Aespoe diorite (70%) components. The backfill composition has been estimated in accordance with mineral quantities present in the components of the backfill mixture. The initial groundwater sucked into the EBS at the repository boundaries is Na-Ca-(HCO3)-SO4-Cl -water having a reference to brackish seawater origin. The reactions considered are cation exchange, surface complexation, and dissolution/precipitation of certain minerals. Calculations assume also diffuse water layers to occur upon the clay platelet surfaces. As an initial condition, the undersaturated pore volumes of backfill and buffer contain entrapped air (O2 content 20%). In the

  2. The Effects of High Salinity Groundwater on the Performance of Clay Barriers

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David [Quintessa Ltd., Nottingham (United Kingdom)

    2005-07-01

    Potential changes in groundwater chemistry during the operational or post-closure periods of the Swedish repository for spent fuel could affect the performance of both the bentonite buffer and repository backfill. For example, the up-coning of saline groundwater could lead to decreased swelling pressures in both the bentonite buffer and tunnel backfills, and could also induce 'piping'. SKB is considering these issues as part of its 'SR-Can' safety assessment. This report reviews evidence for the behaviour of swelling clays in groundwaters of varying salinity with special relevance to the SKB programme. Smectite clays can absorb water into clay inter-layers with the most important parameters being: the surface density of charge of the clay; the charge and solvation behaviour of the inter-layer ions; and the electrolyte concentration or activity of water. Two categories of swelling are generally observed: innercrystalline swelling caused by the hydration of the exchangeable cations in the dry clay; and osmotic swelling, resulting from concentration gradients in ion concentrations between clay surfaces and pore water. Several models exist to interpret and predict the swelling behaviour of clays. SKB currently prefer an interpretation of clay swelling pressure where clay particles are viewed as 'macro-ions' and the entire clay-water system can be considered as a 'polyelectrolyte'. SKB use the term 'Donnan exclusion' to estimate the amount of introduced ions into the clay and hence the amount of reduced swelling pressure due to contact with a saline solution. Donnan exclusion is the process whereby the migration of anions through the narrow aqueous film surrounding clay platelets is restricted due to the repulsion by the negative charge of the clay platelets. SKB's experimental work shows that: There is an exponential relation between swelling pressure and mean basal interlamellar spacing of the clay. Ions from the

  3. Seismic pressure effect on retaining walls; Presiones generadas por sismo en muros de retencion

    Energy Technology Data Exchange (ETDEWEB)

    Bonola, Isaac; Aviles, Javier [Instituto Mexicano de Tecnologia del Agua, Jiutepec, Morelos (Mexico)

    2006-04-15

    Retaining walls are auxiliary works used in different hydraulic structures. In seismically active areas, the dynamic pressures generated by the backfill must be appropriately evaluated at the design stage. Currently, a number of methods for estimating the seismic response of this type of works are available; however, most of them are simplified and not all the parameters involved have been examined. In this paper, a hybrid boundary and finite element method is presented for gravity walls in which the backfill can be represented by a horizontally layered medium. The effect of lateral extension of the backfill can be included in the model by introducing a vertical boundary coupling the movement of the backfill with that of the surrounding soil. The wave propagation analysis in the layered medium is carried out for both horizontal and vertical harmonic excitation; the latter excitation may cause important responses under certain situations. To illustrate the applicability of the proposed method, results for two numerical examples are presented: one for dry backfill and other for saturated backfill, considering in both cases the variations of dynamic properties of the soil with the depth. [Spanish] Los muros de retencion son estructuras auxiliares utilizadas en distintas obras hidraulicas. En zonas sismicas, las presiones dinamicas generadas por el relleno deben evaluarse adecuadamente en la etapa de diseno. Actualmente existen numerosos metodos para estimar la respuesta sismica de este tipo de estructuras; sin embargo, la mayoria de ellos son simplificados y no todos los parametros involucrados han sido examinados. En este trabajo se presenta un metodo hibrido de frontera y elemento finito para muros de gravedad en el que el relleno puede representarse por un medio estratificado horizontalmente. En el modelo puede incluirse el efecto de la extension lateral del relleno, introduciendo una frontera vertical que acopla el movimiento del relleno con el del suelo

  4. Effect of the mineral precipitation-dissolution at tunnel walls during the operational and post-operational phases

    Energy Technology Data Exchange (ETDEWEB)

    Domenech, Cristina; Arcos, David; Duro, Lara; Grandia, Fidel [Enviros Consul ting, Valldoreix, Barcelona (Spain)

    2007-11-15

    The extent of reversibility of the geochemical conditions disturbed during the construction and operational phases is of importance in order to assess the chemical evolution of the repository system. In this regard, it is essential to have a deep understanding of the chemical status of the repository system at closure in order to describe its immediate geochemical evolution beyond this point. This project assesses the dissolution and precipitation of minerals due to the interaction with groundwater in the deposition tunnel wall-rock during the operational phase (prior to tunnel backfilling) and during the saturation phase, also considering the effect on the backfill material. We have performed a 2D model in which a fracture intersecting the main tunnel has been considered. The project has been developed in two consecutive stages. The first stage simulates the precipitation and dissolution of minerals in the tunnel wall rock during the operational phase (100 years after excavation) when the tunnel is empty and filled with air. During this stage, water flows through fractures into the tunnel. The results of the model suggest that the interaction between groundwater, fracture-filling minerals, and atmospheric O{sub 2}(g) and CO{sub 2}(g) present in the tunnel leads to the precipitation of secondary minerals (calcite and iron(III) oxy-hydroxide) that do not significantly affect the porosity of the area surrounding the tunnel. The second stage starts after the operational phase, once the tunnel is backfilled, and simulates the interaction of groundwater with fracture-filling minerals and the backfill material. The model implemented assumes that the backfill is already water saturated and that water flows following the regional head gradient. Moreover, it also assumes that O2(g) is still present in the tunnel wall, as a result of the operational phase disturbances. The results show that oxygen will oxidise pyrite in the backfill and promote the precipitation of Fe

  5. Thermo-Mechanical Behavior of Bentonite Buffer in a Deep Geological HLW Repository

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, S.; Cho, W. J.; Lee, J. O

    2008-08-15

    This work aims to investigate the influence of bentonite buffer and backfill, which will role as important engineered barriers, on the thermo-mechanical behaviors of a disposal system at a deep underground HLW repository. It will contribute to the disposal system development and performance assessment of the system. In this study, three-dimensional computer simulations were carried out with a consideration of the thermal and mechanical characteristics of the buffer and backfill for the investigation of the behavior of buffer and backfill under different disposal conditions. The understanding of the near field response to the variation of buffer and backfill properties will contribute to the development of an adequate buffer and backfill design in disposal conditions as well as the selection of a disposal site. The following conclusions could be drawn from the three-dimensional thermo-mechanical coupling analysis for investigating the possible influence of the bentonite buffer on the thermo-mechanical behavior around an underground repository, which is located at several hundred meters deep underground. o The bentonite swelling pressure can influence on the mechanical behavior of canister. Further detailed modeling is required in the future. o It is required to consider the water content and density of bentonite as important design parameters, because it was found that those influence the thermo-mechanical behavior of near field significantly. o A horizontal deposition hole and multi-level repository can results different maximum temperatures, stress concentration, and the required time for the maximum temperatures of canister, buffer, and rock compared to those of vertical deposition hole and single level repository. o Even though, the same laboratory results were used for driving the parameters for the plastic models used in the modeling, the mechanical behaviors were different. It is, therefore, required to use adequate plastic models for buffer and backfill

  6. Soil Structure Interaction for Integral Abutment Bridge Using Spring Analogy Approach

    International Nuclear Information System (INIS)

    The reaction of the backfill behind the abutments and adjacent to the piles plays a significant role in the behavior of the Integral bridge. The handling of soil-structure interaction in the analysis and design of integral abutment bridges has always been problematic due to its complexity. This study describes the implementation of a 2-D finite element model of IAB system which explicitly incorporates the soil response. The superstructure members and the pile have been represented by means of three-node isoperimetric beam elements with three degree of freedom per node. The Eight node isoperimetric quadrilateral element has been used to model the abutment. The backfill was idealized by uncoupled 'Winkler' spring. The applic1ability of this model is demonstrated by analyzing a single span IA bridge. The results have shown that the shear forces at the tops of the supported piles were only 12% to 16% of the load which at the top of abutment.

  7. Soil Structure Interaction for Integral Abutment Bridge Using Spring Analogy Approach

    Energy Technology Data Exchange (ETDEWEB)

    Thanoon, W A [Faculty Engineering, Nizwa University (Oman); Abdulrazeg, A A; Jaafar, M S; Kohnehpooshi, O [Department of Civil Engineering, University Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Noorzaei, J, E-mail: jamal@eng.upm.edu.my [Institute of Advance Technology, University Putra Malaysia, 43400 Serdang, Selangor (Malaysia)

    2011-02-15

    The reaction of the backfill behind the abutments and adjacent to the piles plays a significant role in the behavior of the Integral bridge. The handling of soil-structure interaction in the analysis and design of integral abutment bridges has always been problematic due to its complexity. This study describes the implementation of a 2-D finite element model of IAB system which explicitly incorporates the soil response. The superstructure members and the pile have been represented by means of three-node isoperimetric beam elements with three degree of freedom per node. The Eight node isoperimetric quadrilateral element has been used to model the abutment. The backfill was idealized by uncoupled 'Winkler' spring. The applic1ability of this model is demonstrated by analyzing a single span IA bridge. The results have shown that the shear forces at the tops of the supported piles were only 12% to 16% of the load which at the top of abutment.

  8. The potential for vault-induced seismicity in nuclear fuel waste disposal: experience from Canadian mines

    International Nuclear Information System (INIS)

    A seismic event which causes damage to an underground opening is called a rockburst. Practical experience indicates that these damaging seismic events are associated with deep mines where extraction ratios are greater than 0.6. For the arrangement being considered by AECL for nuclear fuel waste disposal vaults, extraction ratios, for the room and pillar design, will be less than 0.3. At this extraction ratio the stress magnitudes will not be sufficient to induce seismic events that can damage the underground openings. Documented world-wide experience shows that unless the underground opening is very close to the source of a naturally occurring seismic event, such as an earthquake, the opening will also not experience any significant damage. Backfilling a disposal vault will improve its resistance to earthquake damage. Backfilling a disposal vault will also reduce the total convergence of the openings caused by thermal loads and hence minimize the potential for thermally-induced seismic events. (author)

  9. Waste package performance analysis

    International Nuclear Information System (INIS)

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been applied to several package designs. The resulting preliminary assessments were intended for use in making decisions about package development programs. A computer model called BARIER estimates the package life and subsequent rate of release of selected nuclides. The model accounts for temperature, pressure (and resulting stresses), bulk and localized corrosion, and nuclide retardation by the backfill after water intrusion into the waste form. The assessment model assumes a post-closure, flooded, geologic repository. Calculations indicated that, within the bounds of model assumptions, packages could last for several hundred years. Intact backfills of appropriate design may be capable of nuclide release delay times on the order of 107 yr for uranium, plutonium, and americium. 8 references, 6 figures, 9 tables

  10. Mechanism of Geogrid Reinforced Soil at Bridge Approach

    Institute of Scientific and Technical Information of China (English)

    FENG Guangle; LUO Rong; CHEN Congxin

    2007-01-01

    Using Geogrid-Reinforced Soil (GRS) we studied the working mechanism and design method of GRS at bridge approach with high backfill by field experiment. In a highway section where the height of backfill is 13.5 meters, geogrids were used at two bridge approaches to address the bumping problems. Some soil pressure cells were used to measure the normal and lateral soil pressure at different locations in the roadbed. The experimental results indicate that geogrids in geogrid-reinforced soil (GRS) could produce an uplift force, the closer the location to the abutment, the larger the uplift force, and the reduction of measured soil pressures compared with theoretical values was the largest at the bottom of roadbed, less at the top than at the bottom, and the least in the mid-height of roadbed than at the bottom. These findings are different from those of the traditional greogrid-reinforced subgrade design method.

  11. Assessing materials (''Getters'') to immobilize or retard the transport of technetium through the engineered barrier system at the potential Yucca Mountain nuclear waste repository

    Energy Technology Data Exchange (ETDEWEB)

    Viani, B E

    1999-03-15

    Current performance assessment calculations show that technetium (Tc) and neptunium (Np) will deliver the major fraction of the radiation dose to the accessible environment from the potential Yucca Mountain nuclear waste repository. Therefore, materials that can immobilize or delay the transport of Tc or Np (getters) are being considered for addition to either the waste-package or the backfill adjacent to the waste-package. Of the two radionuclides, Tc presents the greater challenge in identifying a suitable getter material. This report identifies several materials that warrant further consideration for immobilizing and/or sorbing Tc as additives to the backfill, and recommends active carbon and an inorganic oxide for initial testing. Other materials, such as zero valent iron, might be useful as getters if they were placed in the waste package itself, a subject that merits further investigation.

  12. Equilibrium leach testing of Magnox swarf and sludge

    International Nuclear Information System (INIS)

    A static equilibrium leach test has been developed to simulate repository conditions after ground water has penetrated the near field barrier. The repository components - waste, matrix and backfill - have been equilibrated with water for up to one year. Leachates were analysed for U, Pu, Np237, Am241, Cs137, Sr90, Tc99, I129 and C14. Results are presented for leaching from Magnox fuel cladding wastes using a combination of matrices, backfills and atmospheric conditions. The equilibrium concentrations were generally very low and have been compared with the concentration of each isotope in drinking water that would give an adult an annual effective dose equivalent of 0.1mSv. (author)

  13. Behavior of a Nuclear Power Plant Ventilation Stack for Wind Loads

    Science.gov (United States)

    Venkatachalapathy, V.

    2012-05-01

    This paper describes behavior of self supporting tall reinforced concrete (RC) ventilation stack of a nuclear power plant (NPP) for wind loads. Since the static and equivalent dynamic wind loads are inter-dependant on overall size of the stack, proper sizing of the stack geometry is important for reducing wind loads. The present study investigated the influence of engineered backfill soil on lateral response of ventilation stack. Ignoring backfill soil stiffness up to ground height does not allow to predict actual critical wind velocity causing across wind oscillation. The results show that proposed modification in the stack geometry modeled using 2D beam-spring elements is economical than that of single tapered geometry. Shaft diameter reduced in the proposed geometry indicates that there is a scope for overall space savings in the NPP layout.

  14. Direct methods of soil-structure interaction analysis for earthquake loadings(II)

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Chung Bang; Lee, S. R.; Kim, J. M.; Park, K. L.; Oh, S. B.; Choi, J. S.; Kim, Y. S. [Korea Advanced Institute of Science Technology, Daejeon (Korea, Republic of)

    1994-07-15

    In this study, methods for 3-D soil-structure interaction analysis have been studied. They are 3-D axisymmetric analysis method, 3-D axisymmetric finite element method incorporating infinite elements, and 3-D boundary element methods. The computer code, named as 'KIESSI - PF', has been developed which is based on the 3-D axisymmetric finite element method coupled with infinite element method. It is able to simulate forced vibration test results of a soil-structure interaction system. The Hualien FVT post-correlation analysis before backfill and the blind prediction analysis after backfill have been carried out using the developed computer code 'KIESSI - PF'.

  15. Numerical Simulation of Heat Transfer Characteristics of Horizontal Ground Heat Exchanger in Frozen Soil Layer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simplified numerical model of heat transfer characteristics of horizontal ground heat exchanger (GHE) in the frozen soil layer is presented and the steady-state distribution of temperature field is simulated. Numerical results show that the frozen depth mainly depends on the soil's moisture content and ambient temperature. The heat transfer loss of horizontal GHE tends to grow with the increase of the soil's moisture content and the decrease of ambient temperature. Backfilled materials with optimal thermal conductivity can reduce the thermal loss effectively in the frozen soil. The applicability of the Chinese national standard "Technical Code for Ground Source Heat Pump (GB 50366-2005)" is verified. For a ground source heat pump project, the feasible layout of horizontal GHE should be determined based on the integration of the soil's structure, backfilled materials,weather data, and economic analysis.

  16. The equilibrium leach testing of CAGR hulls

    International Nuclear Information System (INIS)

    Equilibrium leach tests were carried out on a laboratory scale in order to investigate the long-term performance of an intermediate level waste repository. The tests involved leaching fully active Commercial Advanced Gas-cooled Reactor (CAGR) hulls in the presence of crushed matrix and backfill materials. The matrix materials used were blast furnace slag (BFS)/ordinary Portland cement (OPC) and epoxide MS7531/MS7532, and the backfill materials were bentonite and pulverised fuel ash/ordinary Portland cement (PFA/OPC). Comparison of the long-lived radionuclide concentrations with the derived drinking water levels indicates that the performance of a repository under oxidising conditions would tend to be limited by the release of I-129 and Tc-99. (author)

  17. Soil-Structure Interaction for Non-Slender, Large-Diameter Offshore Monopiles

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal

    . The monopile foundation concept has been employed as the foundation for the majority of the currently installed offshore wind turbines. Therefore, this PhD thesis concerns the soil-pile interaction for non-slender, large-diameter offshore piles. A combination of numerical and physical modelling has...... University. Hence, the application of an overburden pressure is possible. The timescale of the backfill process and the compaction of soil material backfilled around piles in storm conditions have been investigated by means of large-scale physical modelling....... been conducted. The initial part of p-y curves for non-slender piles has been investigated by means of numerical modelling. The general behaviour of eccentrically loaded non-slender piles has been investigated by physical modelling. These tests have been conducted in the pressure tank at Aalborg...

  18. Using a multiphase flow code to model the coupled effects of repository consolidation and multiphase brine and gas flow at the Waste Isolation Pilot Plant

    International Nuclear Information System (INIS)

    Long-term repository assessment must consider the processes of (1) gas generation, (2) room closure and expansions due to salt creep, and (3) multiphase (brine and gas) fluid flow, as well as the complex coupling between these three processes. The mechanical creep closure code SANCHO was used to simulate the closure of a single, perfectly sealed disposal room filled with water and backfill. SANCHO uses constitutive models to describe salt creep, waste consolidation, and backfill consolidation, Five different gas-generation rate histories were simulated, differentiated by a rate multiplier, f, which ranged from 0.0 (no gas generation) to 1.0 (expected gas generation under brine-dominated conditions). The results of the SANCHO f-series simulations provide a relationship between gas generation, room closure, and room pressure for a perfectly sealed room. Several methods for coupling this relationship with multiphase fluid flow into and out of a room were examined. Two of the methods are described

  19. Oil shale mining cost analysis. Volume I. Surface retorting process. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Resnick, B.S.; English, L.M.; Metz, R.D.; Lewis, A.G.

    1981-01-01

    An Oil Shale Mining Economic Model (OSMEM) was developed and executed for mining scenarios representative of commercially feasible mining operations. Mining systems were evaluated for candidate sites in the Piceance Creek Basin. Mining methods selected included: (1) room-and-pillar; (2) chamber-and-pillar, with spent shale backfilling; (3) sublevel stopping; and (4) sublevel stopping, with spent shale backfilling. Mines were designed to extract oil shale resources to support a 50,000 barrels-per-day surface processing facility. Costs developed for each mining scenario included all capital and operating expenses associated with the underground mining methods. Parametric and sensitivity analyses were performed to determine the sensitivity of mining cost to changes in capital cost, operating cost, return on investment, and cost escalation.

  20. Dynamic stiffness of pile groups in a multilayered soil. Part 1

    International Nuclear Information System (INIS)

    For evaluating the dynamic stiffness of the pile group foundations, forced vibration tests are executed on pile group foundation models. Two types of test models are used, one is a single pile model and the other a four-pile model. Dividing the tests into 4 steps, the forced vibration tests are performed. Step 1 is for the single pile model, and steps 2 to 4 are for the four-pile model. In step 2 and step 3, the gap effects between the foundation bottom and the ground surface are examined. In step 4, the backfill effects are obtained. Based on the test results, the pile group effects, the gap effects and the backfill effects on the dynamic characteristics of the pile group foundations are described in this paper

  1. Scour Development around Bucket Foundations

    DEFF Research Database (Denmark)

    Stroescu, Ionut Emanuel; Frigaard, Peter Bak; Fejerskov, Morten

    2015-01-01

    The design without scour protection is a sensitive topic to most offshore developers, especially in the North Sea. However, newer research show that this concept is realistic if exists extended comprehension of the scour and backfill phenomena. The present paper shows comparative results for mono......The design without scour protection is a sensitive topic to most offshore developers, especially in the North Sea. However, newer research show that this concept is realistic if exists extended comprehension of the scour and backfill phenomena. The present paper shows comparative results...... for monopile and Bucket Foundation; using experimental analysis and real scour surveys around offshore installed Bucket Foundations. The main finding reflect that Bucket Foundation is a candidate for design without scour protection behaving like scour protected monopoles, in a variety of environmental...

  2. Joint DOE/NRC field study of tracer migration in the unsaturated zone

    Energy Technology Data Exchange (ETDEWEB)

    Nyhan, J.; Polzer, W.; Essington, E.; Cokal, E.; Lane, L.; Lopez, E.; Stallings, E.; Walker, R.

    1986-03-01

    The results of a joint DOE/NRC field experiment to evaluate leaching and transport of solutes in a sandy silt backfill used for shallow land burial operations at Los Alamos are presented for steady-state and unsteady-state flow conditions. The migration of iodide, bromide, and lithium through the backfill material is studied as functions of depth and time and they are compared with one another. The bromide and iodide tracer data are used to estimate the diffusion coefficient, the tortuosity factor, and dispersivity. These values are used to calculate effective dispersion coefficients for subsequent analyses of the retardation factor and the distribution coefficient for lithium using least squares procedures. The results of the tracer migration study are discussed relative to challenges facing the waste management community, and chemical transport modeling opportunities are presented for a modeling workshop to be held in FY86.

  3. Loads on Entrance Platforms for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Frigaard, Peter; Andersen, Thomas Lykke; Ramirez, Jorge Robert Rodriguez;

    2010-01-01

    The present paper gives an overview of the performed large scale tests in GWK, Hannover for studying wave run-up generated forces on wind turbine entrance platforms. The run-up height and velocity was measured by use of high speed video recordings supplemented by some wave gauges mounted at the p......The present paper gives an overview of the performed large scale tests in GWK, Hannover for studying wave run-up generated forces on wind turbine entrance platforms. The run-up height and velocity was measured by use of high speed video recordings supplemented by some wave gauges mounted...... at the pile. Hereafter, the run-up generated impact forces were measured on two types of grates and a solid plate. The pressure distribution was also measured for the solid plate. In addition to this the wave generated backfilling of an initial scour hole and the strength of the backfilling soil was studied...

  4. Thermal simulation of drift emplacement (TSS): In-situ instrumentation and numerical modeling of stress measurement methods

    International Nuclear Information System (INIS)

    In the course of the planned demonstration test Thermal Simulation of Drift Emplacement (TSS) BGR is carrying out in-situ-measurements of rock stresses, rock deformability and permeability of salt rock and backfill material. The following techniques developed and proved by BGR during the last years are planned to be used in the TSS project: overcoring technique, dilatometer technique, hard inclusion technique, slot-cutting techniques, large-flatjack technique, compensation tests in laboratory, vacuum tests, injection tests, and tracer tests. The purpose of measurements is to determine: the initial stress state; stress gradients around test drifts; stress change caused by mining activities, by creep and stress relaxation and by temperature; the in-situ load-deformation behavior of rock salt; the permeability of rock salt around test drifts; the compaction behavior of backfill material; and the load-deformation behavior of rock salt and borehole grout in laboratory tests

  5. Characteristics of thermally-enhanced bentonite grouts for geothermal heat exchanger in South Korea

    Institute of Scientific and Technical Information of China (English)

    Chulho; LEE; Kangja; LEE; Hangseok; CHOI; Hyo-Pum; CHOI

    2010-01-01

    The thermal conductivity and viscosity of bentonite grouts have been evaluated and compared each other to determine the suitability of these materials for backfilling vertical boreholes of ground heat exchangers.Seven bentonite grouts from different product sources were considered in this paper.Two additives,silica sand and graphite were added in bentonite grouts to enhance thermal performance.The bentonite grouts indicate that both the thermal conductivity and the viscosity increase with the content of silica sand and graphite.Therefore,it is recommended to select cautiously the amount of silica sand and graphite considering not only thermal conductivity but also viscosity for the optimum condition of backfilling.Finally,the effect of salinity in the pore water on the change of swelling potential of the bentonite-based grouts has been quantitatively evaluated to show the feasibility of bentonite grouts in the coastal area.

  6. An in vitro model to investigate filling of lateral canals.

    Science.gov (United States)

    Venturi, Mauro; Di Lenarda, Roberto; Prati, Carlo; Breschi, Lorenzo

    2005-12-01

    Aims of this work were to examine lateral canals in extracted teeth, to propose a new technique to produce artificial lateral canals, and to compare two obturation techniques. Cleared roots were examined to record measure and shape of lateral canals. Artificial lateral canals were prepared on human demineralized teeth before final clearing. Specimens were divided in two groups: canals of group 1 were filled with Schilder's technique, canals of group 2 were filled with vertical compaction with apical backfilling. Stereomicroscopic analysis of lateral canal filling revealed lower filling rates in apical canals compared to coronal ones and higher filling rates with "vertical compaction with apical backfilling" compared to Schilder's group. The tested procedure appears to be a reliable technique to obtain standardized lateral canals and to compare filling procedures.

  7. Utilization of SRS pond ash in controlled low strength material. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C.A.; Rajendran, N.

    1995-12-01

    Design mixes for Controlled Low Strength Material (CLSM) were developed which incorporate pond ashes (fly ashes) from the A-Area Ash Pile, the old F-Area Ash Basin and the D-Area Ash Basin. CLSM is a pumpable, flowable, excavatable backfill used in a variety of construction applications at SRS. Results indicate that CLSM which meets all of the SRS design specifications for backfill, can be made with the A-, D-, and F-Area pond ashes. Formulations for the design mixes are provided in this report. Use of the pond ashes may result in a cost savings for CLSM used at SRS and will utilize a by-product waste material, thereby decreasing the amount of material requiring disposal.

  8. Forced vibration test of the Hualien large scale SSI model

    International Nuclear Information System (INIS)

    A Large-Scale Seismic Test (LSST) Program has been conducted at Hualien, Taiwan (Tang et al., 1991), to obtain earthquake-induced soil-structure interaction (SSI) data in a stiff soil site environment The Hualien program is a follow on of the Lotung program which is of soft soil site. Forced vibration tests of the Hualien 1/4-scale containment SSI test model were conducted in October, 1992 before backfill (without embedment) and in February, 1993 after backfill (with embedment) for the purpose of defining basic dynamic characteristics of the soil-structure system. Two horizontal directions excitation (NS, EW) are applied on the roof floor and on the basemat. Vertical excitation is applied on the basemat only. This paper describes the results of the forced vibration tests of the model without embedment. (author)

  9. Standard test method for laboratory evaluation of magnesium sacrificial anode test specimens for underground applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1997-01-01

    1.1 This test method covers a laboratory procedure that measures the two fundamental performance properties of magnesium sacrificial anode test specimens operating in a saturated calcium sulfate, saturated magnesium hydroxide environment. The two fundamental properties are electrode (oxidation potential) and ampere hours (Ah) obtained per unit mass of specimen consumed. Magnesium anodes installed underground are usually surrounded by a backfill material that typically consists of 75 % gypsum (CaSO4·2H2O), 20 % bentonite clay, and 5 % sodium sulfate (Na2SO4). The calcium sulfate, magnesium hydroxide test electrolyte simulates the long term environment around an anode installed in the gypsum-bentonite-sodium sulfate backfill. 1.2 This test method is intended to be used for quality assurance by anode manufacturers or anode users. However, long term field performance properties may not be identical to property measurements obtained using this laboratory test. Note 1—Refer to Terminology G 15 for terms used ...

  10. PILOT-SCALE EVALUATION OF ENGINEERED BARRIER SYSTEMS FOR THE YUCCA MOUNTAIN PROJECT

    International Nuclear Information System (INIS)

    This paper describes two quarter-scale experiments (1.4 m diameter) and associated numerical analyses on granular backfill engineered barrier systems in support of the Yucca Mountain Project for the potential repository. The two configurations include a sloped capillary barrier and a plain backfill. The tests involve application of dyed water as a constant line infiltration source along the top of the test set-up, monitoring water movement through the test, and measuring water exiting the experiments. A complete water balance estimate is made for each test, and observed water movement is compared with (1) detailed numerical analyses conducted using the TOUGH2 code for unsaturated flow in porous media and (2) posttest observations. The results of the testing and analyses show that for the injection rates and configuration applied, the capillary barrier design diverts a significant amount of all injected water and the TOUGH2 pretest predictions show qualitative and quantitative agreement with the experimental data

  11. Particle-scale Analysis of Key Technologies on Cut-and-over Tunnel in Slope Engineering

    Directory of Open Access Journals (Sweden)

    J.H. Yang

    2014-08-01

    Full Text Available When the shallow tunnel is constructed on the slope terrain in the mountains, there are the potential risks such as landslide induced by cutting the slope and the non-compacted backfill material during the construction of the cut-andcover tunnel. In order to solve these problems, based on a practical engineering, the optimized construction plans of the cut-and-cover tunnel were analyzed by particle flow code (PFC, the key parts of the open-cut construction were identified, and the anti-slide piles countermeasures were proposed. Furthermore, the grouting reinforcement process for the non-compacted backfill material around the shallow tunnel was simulated by PFC, and the variation characteristics of the porosity and grouting pressure were revealed as well. The results are of great value to the similar engineering.

  12. Treatment and final disposal of nuclear waste. Programme for encapsulation, deep geological disposal, and research, development and demonstration

    International Nuclear Information System (INIS)

    Programs for RD and D concerning disposal of radioactive waste are presented. Main topics include: Design, testing and manufacture of canisters for the spent fuels; Design of equipment for deposition of waste canisters; Material and process for backfilling rock caverns; Evaluation of accuracy and validation of methods for safety analyses; Development of methods for defining scenarios for the safety analyses. 471 refs, 67 figs, 21 tabs

  13. Expected environments in high-level nuclear waste and spent fuel repositories in salt

    Energy Technology Data Exchange (ETDEWEB)

    Claiborne, H.C.; Rickertsen, L.D., Graham, R.F.

    1980-08-01

    The purpose of this report is to describe the expected environments associated with high-level waste (HLW) and spent fuel (SF) repositories in salt formations. These environments include the thermal, fluid, pressure, brine chemistry, and radiation fields predicted for the repository conceptual designs. In this study, it is assumed that the repository will be a room and pillar mine in a rock-salt formation, with the disposal horizon located approx. 2000 ft (610 m) below the surface of the earth. Canistered waste packages containing HLW in a solid matrix or SF elements are emplaced in vertical holes in the floor of the rooms. The emplacement holes are backfilled with crushed salt or other material and sealed at some later time. Sensitivity studies are presented to show the effect of changing the areal heat load, the canister heat load, the barrier material and thickness, ventilation of the storage room, and adding a second row to the emplacement configuration. The calculated thermal environment is used as input for brine migration calculations. The vapor and gas pressure will gradually attain the lithostatic pressure in a sealed repository. In the unlikely event that an emplacement hole will become sealed in relatively early years, the vapor space pressure was calculated for three scenarios (i.e., no hole closure - no backfill, no hole closure - backfill, and hole closure - no backfill). It was assumed that the gas in the system consisted of air and water vapor in equilibrium with brine. A computer code (REPRESS) was developed assuming that these changes occur slowly (equilibrium conditions). The brine chemical environment is outlined in terms of brine chemistry, corrosion, and compositions. The nuclear radiation environment emphasized in this report is the stored energy that can be released as a result of radiation damage or crystal dislocations within crystal lattices.

  14. The influence of sintering time on the properties of PM duplex stainless steel

    OpenAIRE

    Z. Brytan; L.A. Dobrzański; M. Actis Grande; M. Rosso

    2009-01-01

    Purpose: The purpose of this paper is to analyse the effect of sintering time on the pore morphology, microstructural changes, tensile properties and corrosion resistance of vacuum sintered duplex stainless steel.Design/methodology/approach: In presented study PM duplex stainless steels were obtained through mixing base ferritic stainless steel powder with controlled addition of elemental alloying powders and then sintered in a vacuum furnace with argon backfilling at 1250°C for different tim...

  15. Field Performance of Recycled Plastic Foundation for Pipeline

    OpenAIRE

    Seongkyum Kim; Kwanho Lee

    2015-01-01

    The incidence of failure of embedded pipelines has increased in Korea due to the increasing applied load and the improper compaction of bedding and backfill materials. To overcome these problems, a prefabricated lightweight plastic foundation using recycled plastic was developed for sewer pipelines. A small scale laboratory chamber test and two field tests were conducted to verify its construction workability and performance. From the small scale laboratory chamber test, the applied loads at ...

  16. Engineered barrier development for a nuclear waste repository in basalt: an integration of current knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.J.

    1980-05-01

    This document represents a compilation of data and interpretive studies conducted as part of the engineered barriers program of the Basalt Waste Isolation Project. The overall objective of these studies is to provide information on barrier system designs, emplacement and isolation techniques, and chemical reactions expected in a nuclear waste repository located in the basalts underlying the Hanford Site within the state of Washington. Backfills, waste-basalt interactions, sorption, borehole plugging, etc., are among the topics discussed.

  17. Plasticity in soil-structure interaction applied to cut-and-cover tunnels

    OpenAIRE

    Plumey, Sylvain; Muttoni, Aurelio; Vulliet, Laurent; Labiouse, Vincent

    2004-01-01

    Cut-and-cover tunnels behavior at ultimate limit state depends strongly on the interactions between the foundation soil, the backfill and the reinforced concrete structure. Characterization of the potential failure modes of these types of structure necessitates taking into account every major mechanical property of each components. The influence of the structure plastic behavior on the ultimate limit state of the soil-structure system is discussed through a basic case study of soil mechanics....

  18. Deep Trenching Protection of Subsea Pipeline Crossing Channel%跨航道海底管道的深挖沟保护

    Institute of Scientific and Technical Information of China (English)

    杜喜军; 赵杰

    2015-01-01

    深挖沟填埋是对跨航道海底管道保护最常用也是最经济有效的方法.在制定深挖沟施工方案时需要重点考虑几个关键参数,包括土壤剪切强度、海底管道抗弯曲强度、挖沟机械设备的能力、挖沟回填的工程量等.挖沟后调查能够检测并及时反馈挖沟效果,是保证挖沟质量的关键.深挖沟后的沟槽回填是一项必不可少的工作.通过具体工程案例,分析了跨航道海底管道4 m深挖沟的影响因素,根据施工现场的实际情况制定了合理的挖沟方案,顺利完成跨航道海底管道的深挖沟掩埋工作.%Deep trenching and backfilling is the most common and the most economical method to protect subsea pipeline crossing channel. During deep trenching construction, there are several key parameters that is important, including shear strength of soil, bending strength of subsea pipeline, trenching equipment, quantity of backfilling etc. Trenching survey is able to detect and feedback the trench depth timely and it is the key to ensure the quality of trenching. Backfilling is an essential task. Through a specific Project, it analyzes the main factors affecting 4 meters depth trenching of subsea pipeline crossing channel, makes a reasonable trenching program based on the actual situation, and completes the task of trenching and backfilling successfully.

  19. Treatment and final disposal of nuclear waste. Programme for encapsulation, deep geological disposal, and research, development and demonstration

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    Programs for RD and D concerning disposal of radioactive waste are presented. Main topics include: Design, testing and manufacture of canisters for the spent fuels; Design of equipment for deposition of waste canisters; Material and process for backfilling rock caverns; Evaluation of accuracy and validation of methods for safety analyses; Development of methods for defining scenarios for the safety analyses. 471 refs, 67 figs, 21 tabs.

  20. The Reverse Approach for Monopile Scour

    DEFF Research Database (Denmark)

    Hartvig, Peres Akrawi

    2012-01-01

    The present paper deals with the theoretical and numerical modeling of scouring and backfilling around an offshore monopile. Based on existing relations for the bed load and the bed update, and a new model for the sediment pickup, it demonstrates the possibility of computing the mean bed shear st...... stress if the bed and bed update is estimated. The present concepts may be useful for developing methods for scour forecasting....

  1. Implementation of the Barcelona Basic Model into TOUGH-FLAC for simulations of the geomechanical behavior of unsaturated soils

    Energy Technology Data Exchange (ETDEWEB)

    Rutqvist, J.; Ijiri, Y.; Yamamoto, H.

    2010-06-01

    This paper presents the implementation of the Barcelona Basic Model (BBM) into the TOUGH-FLAC simulator analyzing the geomechanical behavior of unsaturated soils. We implemented the BBM into TOUGH-FLAC by (1) extending an existing FLAC{sup 3D} module for the Modified Cam-Clay (MCC) model in FLAC{sup 3D} and (2) adding computational routines for suction-dependent strain and net stress (i.e., total stress minus gas pressure) for unsaturated soils. We implemented a thermo-elasto-plastic version of the BBM, wherein the soil strength depends on both suction and temperature. The implementation of the BBM into TOUGH-FLAC was verified and tested against several published numerical model simulations and laboratory experiments involving the coupled thermal-hydrological-mechanical (THM) behavior of unsaturated soils. The simulation tests included modeling the mechanical behavior of bentonite-sand mixtures, which are being considered as back-fill and buffer materials for geological disposal of spent nuclear fuel. We also tested and demonstrated the use of the BBM and TOUGH-FLAC for a problem involving the coupled THM processes within a bentonite-backfilled nuclear waste emplacement tunnel. The simulation results indicated complex geomechanical behavior of the bentonite backfill, including a nonuniform distribution of buffer porosity and density that could not be captured in an alternative, simplified, linear-elastic swelling model. As a result of the work presented in this paper, TOUGH-FLAC with BBM is now fully operational and ready to be applied to problems associated with nuclear waste disposal in bentonite-backfilled tunnels, as well as other scientific and engineering problems related to the mechanical behavior of unsaturated soils.

  2. PreBIND and Textomy – mining the biomedical literature for protein-protein interactions using a support vector machine

    OpenAIRE

    Baskin Berivan; Zhang Shudong; Tuekam Brigitte; Lay Vicki; Wolting Cheryl; de Bruijn Berry; Martin Joel; Donaldson Ian; Bader Gary D; Michalickova Katerina; Pawson Tony; Hogue Christopher WV

    2003-01-01

    Abstract Background The majority of experimentally verified molecular interaction and biological pathway data are present in the unstructured text of biomedical journal articles where they are inaccessible to computational methods. The Biomolecular interaction network database (BIND) seeks to capture these data in a machine-readable format. We hypothesized that the formidable task-size of backfilling the database could be reduced by using Support Vector Machine technology to first locate inte...

  3. Use of engineered soils and other site modifications for low-level radioactive waste disposal

    International Nuclear Information System (INIS)

    The U.S. Nuclear Regulatory Commission requires that low-level radioactive waste (LLW) disposal facilities be designed to minimize contact between waste and infiltrating water through the use of site design features. The purpose of this investigation is to identify engineered barriers and evaluate their ability to enhance the long-term performance of an LLW disposal facility. Previously used barriers such as concrete overpacks, vaults, backfill, and engineered soil covers, are evaluated as well as state-of-the-art barriers, including an engineered sorptive soil layer underlying a facility and an advanced design soil cover incorporating a double-capillary layer. The purpose of this investigation is also to provide information in incorporating or excluding specific engineered barriers as part of new disposal facility designs. Evaluations are performed using performance assessment modeling techniques. A generic reference disposal facility design is used as a baseline for comparing the improvements in long-term performance offered by designs incorporating engineered barriers in generic and humid environments. These evaluations simulate water infiltration through the facility, waste leaching, radionuclide transport through the facility, and decay and ingrowth. They also calculate a maximum (peak annual) dose for each disposal system design. A relative dose reduction factor is calculated for each design evaluated. The results of this investigation are presented for concrete overpacks, concrete vaults, sorptive backfill, sorptive engineered soil underlying the facility, and sloped engineered soil covers using a single-capillary barrier and a double-capillary barrier. Designs using combinations of barriers are also evaluated. These designs include a vault plus overpacks, sorptive backfill plus overpacks, and overpack with vault plus sorptive backfill, underlying sorptive soil, and engineered soil cover

  4. CATSIUS CLAY PROJECT: Calculation and testing of behaviour of unsaturated clay as barrier in radioactive waste repositories: stage 3: validation exercises at a large in situ scale

    International Nuclear Information System (INIS)

    Stage 3 of CATSIUS CLAY Project: Validation Exercises at a Large in situ Scale includes two Benchmarks: Benchmark 3.1: In situ Hydration of Boom Clay Pellets (BACCHUS 2) and Benchmark 3.2: FEBEX Mock-up Test. The BACCHUS 2 in situ test was performed in the HADES underground laboratory (Mol, Belgium) to demonstrate and optimize an installation procedure for a clay based material and to study its hydration process. After drilling a vertical shaft (540 mm in diameter, 3.0 m in length) in the host Boom clay, a central filter (90 mm in diameter) was placed, the remaining space was filled with a mixture of clay pellets and clay powder and the assembly was sealed at the upper end by a resin plug (0.20 m in thickness) over which concrete was poured. The test was instrumented so that it could be used as a validation experiment. Total stress, pore water pressure and water content measurements were performed both in the backfill material and in the surrounding clay massif. Once the installation was complete, the natural hydration of the backfill material began (day 0). To accelerate the hydration process, on day 516 water was injected through the central filter. On day 624, after the saturation of the backfill was reached, the hydraulic circuit was closed and the undrained response of the system backfill-host clay was monitored until an overall steady state was reached. Partners were asked to provide predictions for the evolution of the pore water pressure and total pressure of various points where appropriate sensors are installed. This benchmark addresses the Hydro-Mechanical response of an unsaturated low density clay barrier under natural and artificial hydration. (Author)

  5. Alkaline activation of ceramic waste materials

    OpenAIRE

    REIG CERDÁ, LUCÍA; Tashima, M. M.; Soriano, L.; Borrachero, M. V.; Monzó, J.; Payá, J.

    2013-01-01

    Ceramic materials represent around 45 % of construction and demolition waste, and originate not only from the building process, but also as rejected bricks and tiles from industry. Despite the fact that these wastes are mostly used as road sub-base or construction backfill materials, they can also be employed as supplementary cementitious materials, or even as raw material for alkali-activated binders This research aimed to investigate the properties and microstructure of alkali-activated cem...

  6. Feasibility of an Integrated Thin Seam Coal Mining and Waste Disposal System

    OpenAIRE

    Basu, Kohinoor

    1997-01-01

    The depletion of more attractive thicker and easily accessible coal seams in the central Appalachia will direct attention towards the extraction of coal seams thinner than 28 in. This thesis investigates the feasibility of an integrated mining and backfilling system applicable to thin seams. Two conceptual mining systems, namely Auger mining and Self Advancing Miner, have been proposed for this purpose. Both these systems are designed to remotely mine coal from the seams. Several ...

  7. Research program to study the gamma radiation effects in Spanish bentonites

    International Nuclear Information System (INIS)

    The engineering barrier of a radioactive waste underground disposal facility, placed in a granitic host rock, will consist of a backfill of compacted bentonite blocks. At first, this material will be subjected to a gamma radiation field, from the waste canister, and heat from the spent fuel inside the canister. Moreover, any groundwater that reaches the repository will saturate the bentonite. For these reasons the performance of the engineered barrier must be carefully assessed in laboratory experiments. (Author)

  8. CATSIUS CLAY PROJECT: Calculation and testing of behaviour of unsaturated clay as barrier in radioactive waste repositories: stage 3: validation exercises at a large in situ scale

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, E. E.; Alcoverro, J.

    1999-07-01

    Stage 3 of CATSIUS CLAY Project: Validation Exercises at a Large in situ Scale includes two Benchmarks: Benchmark 3.1: In situ Hydration of Boom Clay Pellets (BACCHUS 2) and Benchmark 3.2: FEBEX Mock-up Test. The BACCHUS 2 in situ test was performed in the HADES underground laboratory (Mol, Belgium) to demonstrate and optimize an installation procedure for a clay based material and to study its hydration process. After drilling a vertical shaft (540 mm in diameter, 3.0 m in length) in the host Boom clay, a central filter (90 mm in diameter) was placed, the remaining space was filled with a mixture of clay pellets and clay powder and the assembly was sealed at the upper end by a resin plug (0.20 m in thickness) over which concrete was poured. The test was instrumented so that it could be used as a validation experiment. Total stress, pore water pressure and water content measurements were performed both in the backfill material and in the surrounding clay massif. Once the installation was complete, the natural hydration of the backfill material began (day 0). To accelerate the hydration process, on day 516 water was injected through the central filter. On day 624, after the saturation of the backfill was reached, the hydraulic circuit was closed and the undrained response of the system backfill-host clay was monitored until an overall steady state was reached. Partners were asked to provide predictions for the evolution of the pore water pressure and total pressure of various points where appropriate sensors are installed. This benchmark addresses the Hydro-Mechanical response of an unsaturated low density clay barrier under natural and artificial hydration. (Author)

  9. Treatment and disposal of radioactive wastes from nuclear power plants. Program for encapsulation, deep geologic deposition and research, development and demonstration; Kaernkraftavfallets behandling och slutfoervaring. Program foer inkapsling, geologisk djupfoervaring samt forskning, utveckling och demonstration

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    Programs for RD and D concerning disposal of radioactive waste are presented. Main topics include: Design, testing and manufacture of canisters for the spent fuels; Design of equipment for deposition of waste canisters; Material and process for backfilling rock caverns; Evaluation of accuracy and validation of methods for safety analyses; Development of methods for defining scenarios for the safety analyses. 471 refs, 67 figs, 21 tabs.

  10. Three-dimensional porous stretchable and conductive polymer composites based on graphene networks grown by chemical vapour deposition and PEDOT:PSS coating.

    Science.gov (United States)

    Chen, Mengting; Duan, Shasha; Zhang, Ling; Wang, Zhihui; Li, Chunzhong

    2015-02-21

    We have manufactured a highly conductive and stretchable composite by backfilling the 3D graphene-PEDOT:PSS skeleton with poly(dimethylsiloxane) (PDMS). The electrical conductivity of our product can reach 24 S cm(-1) with only 1.5 wt% graphene and 1.5 wt% PEDOT:PSS loading, and its resistance increased only 35% when stretched to 80% strain. PMID:25605259

  11. Proceedings of the Canadian Nuclear Society 2. international conference on radioactive waste management

    International Nuclear Information System (INIS)

    These proceedings contain 136 papers on waste management from 19 countries. An index of the delegates and their affiliations is included. Emphasis was laid on the Canadian program for geologic disposal in hard rock. Sessions dealt with the following: storage and disposal, hydrogeology and geochemistry, transportation, buffers and backfill, public attitudes, tailings, site investigations and geomechanics, concrete, economics, licensing, matrix materials and container design, durability of fuel, biosphere modelling, radioactive waste processing, and future options

  12. Evaluation on Impact Interaction between Abutment and Steel Girder Subjected to Nonuniform Seismic Excitation

    OpenAIRE

    Yue Zheng; Xiang Xiao; Lunhai Zhi; Guobo Wang

    2015-01-01

    This paper aims to evaluate the impact interaction between the abutment and the girder subjected to nonuniform seismic excitation. An impact model based on tests is presented by taking material properties of the backfill of the abutment into consideration. The conditional simulation is performed to investigate the spatial variation of earthquake ground motions. A two-span continuous steel box girder bridge is taken as the example to analyze and assess the pounding interaction between the abut...

  13. Synthesis and characterization of zeolite from waste coal flyash for tailored application in bio-refining and process water cleaning: An innovative approach towards a cleaner circular economy

    OpenAIRE

    Das, Gaurav

    2016-01-01

    The purpose of the investigation was to assess if Finnish coal flyash (CFA) waste could be used to synthesize zeolites. The world produces 750 million tonnes of CFA annually which is also the largest quantity waste produced. This figure will only increase as India, China, South America and Africa charges ahead with industrialization. The global recycle rate is 15% annually. Finland produces about 750,000 tonnes of CFA per year. It is also estimated that millions of tonnes of CFA is backfilled...

  14. Modeling the Electro-Optical Performance of High Power Mid-Infrared Quantum Cascade Lasers

    OpenAIRE

    Hans Dieter Tholl; Quankui Yang; Joachim Wagner

    2016-01-01

    Performance modeling of the characteristics of mid-infrared quantum cascade lasers (MIR QCL) is an essential element in formulating consistent component requirements and specifications, in preparing guidelines for the design and manufacture of the QCL structures, and in assessing different modes of operation of the laser device. We use principles of system physics to analyze the electro-optical characteristics of high power MIR QCL, including thermal backfilling of the lower laser level, hot ...

  15. The sustainability of the Barcelona port enlargement works

    OpenAIRE

    Tarragó, D.; Gens Solé, Antonio; Alonso Pérez de Agreda, Eduardo; Romero Morales, Enrique Edgar; Griell, R.; Estrada, J.L.; Uzcanga, J.

    2011-01-01

    In the Barcelona Port enlargement, currently under construction, part of the new quays are being backfilled with re-used materials such as tunneling waste, rubble from demolitions and dredged soils with poor geotechnical properties. This has resulted in a cost-effective and sustainable construction process that is one of the main goals of the Barcelona Port Authority (APB). A series of control tests have been carried out on the mentioned materials. In addition, dredged soils have been impr...

  16. Expected environments in high-level nuclear waste and spent fuel repositories in salt

    International Nuclear Information System (INIS)

    The purpose of this report is to describe the expected environments associated with high-level waste (HLW) and spent fuel (SF) repositories in salt formations. These environments include the thermal, fluid, pressure, brine chemistry, and radiation fields predicted for the repository conceptual designs. In this study, it is assumed that the repository will be a room and pillar mine in a rock-salt formation, with the disposal horizon located approx. 2000 ft (610 m) below the surface of the earth. Canistered waste packages containing HLW in a solid matrix or SF elements are emplaced in vertical holes in the floor of the rooms. The emplacement holes are backfilled with crushed salt or other material and sealed at some later time. Sensitivity studies are presented to show the effect of changing the areal heat load, the canister heat load, the barrier material and thickness, ventilation of the storage room, and adding a second row to the emplacement configuration. The calculated thermal environment is used as input for brine migration calculations. The vapor and gas pressure will gradually attain the lithostatic pressure in a sealed repository. In the unlikely event that an emplacement hole will become sealed in relatively early years, the vapor space pressure was calculated for three scenarios (i.e., no hole closure - no backfill, no hole closure - backfill, and hole closure - no backfill). It was assumed that the gas in the system consisted of air and water vapor in equilibrium with brine. A computer code (REPRESS) was developed assuming that these changes occur slowly (equilibrium conditions). The brine chemical environment is outlined in terms of brine chemistry, corrosion, and compositions. The nuclear radiation environment emphasized in this report is the stored energy that can be released as a result of radiation damage or crystal dislocations within crystal lattices

  17. Radionuclide getters in the near-field chemistry of repositories

    International Nuclear Information System (INIS)

    The ultimate release of radionuclides from a radioactive waste repository will depend upon the natural and man-made barriers surrounding the site. An opportunity exists to enhance natural radionuclide retention through improved sorption, by the use of suitable additives applied to the repository backfill material. This programme of work was designed to identify problem isotopes, to search for suitable materials to enhance their retention and ultimately to provide, through experimental studies, an understanding of their effectiveness under repository conditions. (Author)

  18. Nuclear waste management. Quarterly progress report, July-September 1980

    Energy Technology Data Exchange (ETDEWEB)

    Chikalla, T.D.

    1980-11-01

    Research is reported on: high-level waste immobilization, alternative waste forms, TRU waste immobilization and decontamination, krypton solidification, thermal outgassing, /sup 129/I fixation, unsaturated zone transport, well-logging instrumentation, waste management system and safety studies, effectiveness of geologic isolation systems, waste/rock interactions, engineered barriers, backfill material, spent fuel storage (criticality), barrier sealing and liners for U mill tailings, and revegetation of inactive U tailings sites. (DLC)

  19. Neuroanatomy of pars intercerebralis neurons with special reference to their connections with neurons immunoreactive for pigment-dispersing factor in the blow fly Protophormia terraenovae.

    Science.gov (United States)

    Yasuyama, Kouji; Hase, Hiroaki; Shiga, Sakiko

    2015-10-01

    Input regions of pars intercerebralis (PI) neurons are examined by confocal and electron microscopies with special reference to their connections with neurons immunoreactive for pigment-dispersing factor (PDF) in the blow fly, Protophormia terraenovae. PI neurons are a prerequisite for ovarian development under long-day conditions. Backfills from the cardiac recurrent nerve after severance of the posterior lateral tracts labeled thin fibers derived from the PI neurons in the superior medial protocerebrum. These PI fibers were mainly synapsin-negative and postsynaptic to unknown varicose profiles containing dense-core vesicles. Backfilled fibers in the periesophageal neuropils, derived from the PI neurons or neurons with somata in the subesophageal zone, were varicose and some were synapsin-positive. Electron microscopy revealed the presence of both presynaptic and postsynaptic sites in backfilled fibers in the periesophageal neuropils. Many PDF-immunoreactive varicosities were found in the superior medial and lateral protocerebrum and double-labeling showed that 60-88 % of PDF-immunoreactive varicosities were also synapsin-immunoreactive. Double-labeling with the backfills and PDF immunocytochemistry showed that the PI fibers and PDF-immunoreactive varicosities were located close to each other in the superior medial protocerebrum. Results of triple-labeling of PI neurons, PDF-immunoreactive neurons and synapsin-immunoreactive terminals demonstrated that the synapsin-positive PDF-immunoreactive varicosities contacted the PI fibers. These data suggest that PI neurons receive synaptic contacts from PDF-immunoreactive fibers, which are derived from circadian clock neurons, of small ventral lateral neurons (previously called OL2) or posterior dorsal (PD) neurons with somata in the pars lateralis. PMID:25971932

  20. Equilibrium leach testing of low level waste. Pt. 1

    International Nuclear Information System (INIS)

    The equilibrium leach test was developed to simulate the chemical conditions in a repository after water has penetrated the near field barriers. The principal components of the repository (the waste, backfill and canister simulant) are equilibrated with water under static conditions to simulate the very low water flows likely to be encountered in the repository. The water is sampled at various times over a 1-2 year period and analysed for radionuclides. Equilibrium leach testing has now been extended to low level wastes and this report describes the effects of different backfill compositions. Later reports will deal with the effects of other variables. A series of experiments have been conducted using four different backfills with ferric floc sludge wastes in both oxidising and reducing environments. The water was sampled at 1, 3, 6 and 12 months and analysed for actinides, fission and activation products and inactive components. It was demonstrated that the activities released depended on the nature of the backfill but not very much on the redox potential of the system. Whereas fission and activation products generally reached steady state values by three months, this was not so for the actinides which had not reached a steady value even after twelve months. Initial experiments using membrane filters indicated this was partly due to the presence of colloidal material in the leachates. Similar tests for the inactive components of the leachates did not show any significant colloidal contribution from these elements except for iron and this only in a few cases. The role of these materials cannot be precluded however, since the amounts required to interact with actinides would be very small and might be difficult to detect. (author)

  1. Model for the Evolving Bed Surface around an Offshore Monopile

    DEFF Research Database (Denmark)

    Hartvig, Peres Akrawi

    2012-01-01

    This paper presents a model for the bed surface around an offshore monopile. The model has been designed from measured laboratory bed surfaces and is shown to reproduce these satisfactorily for both scouring and backfilling. The local rate of the bed elevation is assumed to satisfy a certain...... general parametrized surface. The model also accounts for sliding of sediment particles when the angle of the local bed slope exceeds the angle of repose....

  2. Stripa project, Quarterly report October through December 1981

    International Nuclear Information System (INIS)

    The methodology development for hydrogeological investigations in boreholes is continuing in combination with hydraulic, chemical and isotopic characterization of granites and groundwaters. The migration investigation is continued by drilling sampling holes and desigming the equipment. The first buffer mass tests have covered the measurement of temperature, swelling pressures and water migration in two deposition holes. The preparation of the bentonite/sand backfill has started. (G.B.)

  3. Use of engineered soils and other site modifications for low-level radioactive waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    1994-08-01

    The U.S. Nuclear Regulatory Commission requires that low-level radioactive waste (LLW) disposal facilities be designed to minimize contact between waste and infiltrating water through the use of site design features. The purpose of this investigation is to identify engineered barriers and evaluate their ability to enhance the long-term performance of an LLW disposal facility. Previously used barriers such as concrete overpacks, vaults, backfill, and engineered soil covers, are evaluated as well as state-of-the-art barriers, including an engineered sorptive soil layer underlying a facility and an advanced design soil cover incorporating a double-capillary layer. The purpose of this investigation is also to provide information in incorporating or excluding specific engineered barriers as part of new disposal facility designs. Evaluations are performed using performance assessment modeling techniques. A generic reference disposal facility design is used as a baseline for comparing the improvements in long-term performance offered by designs incorporating engineered barriers in generic and humid environments. These evaluations simulate water infiltration through the facility, waste leaching, radionuclide transport through the facility, and decay and ingrowth. They also calculate a maximum (peak annual) dose for each disposal system design. A relative dose reduction factor is calculated for each design evaluated. The results of this investigation are presented for concrete overpacks, concrete vaults, sorptive backfill, sorptive engineered soil underlying the facility, and sloped engineered soil covers using a single-capillary barrier and a double-capillary barrier. Designs using combinations of barriers are also evaluated. These designs include a vault plus overpacks, sorptive backfill plus overpacks, and overpack with vault plus sorptive backfill, underlying sorptive soil, and engineered soil cover.

  4. Engineered barrier development for a nuclear waste repository in basalt: an integration of current knowledge

    International Nuclear Information System (INIS)

    This document represents a compilation of data and interpretive studies conducted as part of the engineered barriers program of the Basalt Waste Isolation Project. The overall objective of these studies is to provide information on barrier system designs, emplacement and isolation techniques, and chemical reactions expected in a nuclear waste repository located in the basalts underlying the Hanford Site within the state of Washington. Backfills, waste-basalt interactions, sorption, borehole plugging, etc., are among the topics discussed

  5. Condition Assessment Survey (CAS) Program. Deficiency standards and inspections methods manual: Volume 1, 0.01 Foundations and footings

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    General information is presented for asset determinant factor/CAS repair codes/CAS cost factors; guide sheet tool & material listing; testing methods; inspection frequency; standard system design life tables; system work breakdown structure; and general system/material data. Deficiency standards and inspection methods are given for footings - spread/strip/grade beams; foundation walls; foundation dampproofing/waterproofing; excavation/backfill/ and piles & caissons.

  6. Effects of pH and temperature on the swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite

    OpenAIRE

    Ye, Wei-min; ZHENG, Z.J.; Chen,Bao; CHEN, Yong-Gui; Cui, Yu-Jun; Wang, Ju

    2014-01-01

    Gaomiaozi (GMZ) bentonite has been recognized as the first choice for using as buffer/backfill materials in deep geological repository for the disposal of high-level nuclear waste (HLW) in China. Groundwater in Beishan area, which has been considered as a potential site for the construction of Chinese deep geological repository, may reach a high pH value because of its chemical background and possible cement degradation during the operation of the repository. Meanwhile, temperature may increa...

  7. Caractérisation géostatistique de pollutions industrielles de sols: cas des hydrocarbures aromatiques polycycliques sur d'anciens sites de cokeries

    OpenAIRE

    Jeannée, Nicolas

    2001-01-01

    Estimating polycyclic aromatic hydrocarbons concentrations in soil at former industrial sites poses several practical problems on account of the properties of the contaminants and the history of site : - collection and preparation of samples from highly heterogeneous material, - high short scale variability, particularly in presence of backfill, - highly contrasted grades making the variogram inference complicated. The sampling strategy generally adopted for contamined sites is based on the h...

  8. Simulation of the deformation of a stope support design / Abraham Johannes Laubscher

    OpenAIRE

    Laubscher, Abraham Johannes

    2014-01-01

    Supported stope mining is one of the most common types of mining in the modern day gold mining industry. The excavated regions, where ore is extracted, are supported with a combination of roof-bolting, timber packs, backfill, timber props and mechanical prop technologies. In order to install a support system that will be able to absorb the energy released by the elastic movement of the surrounding rock mass and support the unstable hanging wall, it is necessary for the rock eng...

  9. The assessment of borehole cement sealing characteristics by acoustic waveform analysis

    International Nuclear Information System (INIS)

    Acoustic waveform analysis has been used to provide a quantitative analysis of the effectiveness of cement grouting for sealing three adjacent boreholes drilled at Harwell, Oxon, as part of a research programme into the disposal of radioactive wastes into argillaceous formations. Results indicate that bonding at cement/casing and cement/formation interfaces would be inadequate for sealing a radioactive waste repository and the use of a backfilling material such as bentonite is advocated. (U.K.)

  10. Effects of fuel burn-up and cooling periods on thermal responses in a repository for spent nuclear fuels

    International Nuclear Information System (INIS)

    Flexible methods and codes have been developed to calculate thermal responses in a spent nuclear fuel repository located in granitic bedrock. The thermal resistance of the backfill material makes an essential contribution to the temperature at the canister surface. The backfill is however so thin compared to the rock masses of the repository that a stationary solution for the temperature drop across the backfill can be used. Combining analytical solutions of thermal diffusion in the rock and the stationary temperature following the released heat power across the backfill gives a very good description of the thermal behaviour of a repository. Temperatures at different points in a repository were calculated for encapsuled spent fuel with different cooling times (10, 20, 30 and 40 years) and having different burn-up values (33, 35 and 45 MWd/kgU). The amount of spent fuel in each canister was supposed to originate from 1.4 tons of fresh Uranium in the calculated examples. A more crucial variable in a thermal analysis of a repository configuration is however the heat power of canisters as a function of time and not the content of canisters. The study shows that the largest temperature rise at the boundary of a centrally located canister and buffer mass will be at most 85 K with assumed thermal data, when the heat power of 900 canisters does not exceed 1200-1400 W each at the time of emplacement depending on burn-up and cooling time. Assuming a higher value for the heat conductivity of the buffer material corresponding to that of the water saturated bentonite gives 15% higher limits respectively. The canisters were supposed to be placed in 15 rows 25 m apart from each other and 60 canisters in each row. The distance between canisters was taken to be 6 m

  11. Treatment and disposal of radioactive wastes from nuclear power plants. Program for encapsulation, deep geologic deposition and research, development and demonstration

    International Nuclear Information System (INIS)

    Programs for RD and D concerning disposal of radioactive waste are presented. Main topics include: Design, testing and manufacture of canisters for the spent fuels; Design of equipment for deposition of waste canisters; Material and process for backfilling rock caverns; Evaluation of accuracy and validation of methods for safety analyses; Development of methods for defining scenarios for the safety analyses. 471 refs, 67 figs, 21 tabs

  12. Research program to study the gamma radiation effects in Spanish bentonites; Programa de investigacion para estudiar los efectos de la radiacion gamma en bentonitas calcicas espanolas

    Energy Technology Data Exchange (ETDEWEB)

    Dies, J.; Tarrasa, F. [Universidad Politecnica de Catalunya (Spain); Cuevas de las, C.; Miralles, L.; Pueyo, J. J. [Universidad de Barcelona (Spain)

    2000-07-01

    The engineering barrier of a radioactive waste underground disposal facility, placed in a granitic host rock, will consist of a backfill of compacted bentonite blocks. At first, this material will be subjected to a gamma radiation field, from the waste canister, and heat from the spent fuel inside the canister. Moreover, any groundwater that reaches the repository will saturate the bentonite. For these reasons the performance of the engineered barrier must be carefully assessed in laboratory experiments. (Author)

  13. Experimental study on the hydro-mechanical coupling behaviour of highly compacted expansive clay

    OpenAIRE

    Tang, Anh-Minh; Cui, Yu-Jun

    2010-01-01

    Highly compacted expansive clays have been usually considered as a possible material for sealing and backfill in deep geological disposal of radioactive waste. In this condition, the material is simultaneously subjected to water infiltration from the geological barrier and stresses generated by the swelling of engineered barriers in confined conditions. Its behaviour under hydro-mechanical loading is essential to the safe design of the whole storage system. In the present work, MX80 bentonite...

  14. Soft Trencher

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Excavation near existing electrical lines, gas lines and other underground utilities can be dangerous and time consuming. A self propelled trencher called the Soft Trencher developed by Battelle Memorial Institute, Columbus, Ohio uses supersonic air to loosen dirt which is then vacuumed up into a truck or piled into a windrow for later removal of backfill. The supersonic air used to break up the soil is harmless to underground utilities and cables. Unlike traditional excavation methods there ...

  15. Screening evaluation of radionuclide groundwater concentrations for the end state basement fill model Zion Nuclear Power Station decommissioning project

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan T.

    2014-06-09

    ZionSolutions is in the process of decommissioning the Zion Nuclear Power Plant. The site contains two reactor Containment Buildings, a Fuel Building, an Auxiliary Building, and a Turbine Building that may be contaminated. The current decommissioning plan involves removing all above grade structures to a depth of 3 feet below grade. The remaining underground structures will be backfilled with clean material. The final selection of fill material has not been made.

  16. Clasificación morfológica de los rellenos en el trasdós de bóvedas de fábrica

    Directory of Open Access Journals (Sweden)

    Ramos, A.

    2013-12-01

    Full Text Available This paper proposes a classification of the different type of backfill (granular, stiff or masonry backup at the extrados of vaults of historical masonry buildings scattered throughout the Iberian Peninsula. This study, in the mainframe of a broader research program, highlights the structural significance, rather disregarded in literature, of the backfill regarding the structural stability of such constructions. Furthermore, the most common patterns of the arrangement of masonry backup and backfill, as well as some structural considerations, are depicted to illustrate how to evaluate their structural contribution.En este artículo se establece una clasificación de los diferentes tipos de rellenos (rígidos o cementados, granulares firmes o sueltos y aligerados situados en el trasdós de bóvedas y que han podido datarse en diferentes construcciones históricas en el ámbito geográfico de la Península Ibérica. Estos rellenos, tal y como pretende demostrar el estudio más amplio y del que se extrae el presente artículo, tienen una importancia vital para la estabilidad estructural de estas construcciones. Además de la clasificación, se establecen los patrones tipo con los que se encuentran estos rellenos y se introducen algunas de las consideraciones estructurales que deben tenerse en cuenta si se consideran estructuralmente.

  17. Mined salt storage feasibility: Engineering study report

    International Nuclear Information System (INIS)

    This study addresses a method of eliminating the surface storage of mined salt at the Deaf Smith repository site. It provides rough estimates of the logistics and costs of transporting 3.7 million tons of salt from the repository to the salt disposal site near Carlsbad, New Mexico and returning it to the repository for decommissioning backfill. The study assumes that a railcar/truck system will be installed and that the excavated salt will be transported from the repository to an existing potash mine located near Carlsbad, New Mexico approximately 300 miles from the repository. The 3.7 million tons of salt required for repository decommissioning backfill can be stored in the potash mines along with the excess salt, with no additional capital costs required for either a railcar or a truck transportation system. The capital cost for facilities to reclaim the 3.7 million tons of salt from the potash mine is estimated to be $4,400,000 with either a rail or truck transportation system. Segregating the 3.7 million tons of backfill salt in a surface storage area at the potash mine requires a capital cost of $13,900,000 with a rail system or $11,400,000 with a truck system. Transportation costs are estimated at $0.08/ton-mile for rail and $0.13/ton-mile for truck. 2 figs., 5 tabs

  18. Nuclear waste package materials testing report: basaltic and tuffaceous environments

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D.J.; Coles, D.G.; Hodges, F.N.; McVay, G.L.; Westerman, R.E.

    1983-03-01

    The disposal of high-level nuclear wastes in underground repositories in the continental United States requires the development of a waste package that will contain radionuclides for a time period commensurate with performance criteria, which may be up to 1000 years. This report addresses materials testing in support of a waste package for a basalt (Hanford, Washington) or a tuff (Nevada Test Site) repository. The materials investigated in this testing effort were: sodium and calcium bentonites and mixtures with sand or basalt as a backfill; iron and titanium-based alloys as structural barriers; and borosilicate waste glass PNL 76-68 as a waste form. The testing also incorporated site-specific rock media and ground waters: Reference Umtanum Entablature-1 basalt and reference basalt ground water, Bullfrog tuff and NTS J-13 well water. The results of the testing are discussed in four major categories: Backfill Materials: emphasizing water migration, radionuclide migration, physical property and long-term stability studies. Structural Barriers: emphasizing uniform corrosion, irradiation-corrosion, and environmental-mechanical testing. Waste Form Release Characteristics: emphasizing ground water, sample surface area/solution volume ratio, and gamma radiolysis effects. Component Compatibility: emphasizing solution/rock, glass/rock, glass/structural barrier, and glass/backfill interaction tests. This area also includes sensitivity testing to determine primary parameters to be studied, and the results of systems tests where more than two waste package components were combined during a single test.

  19. Nuclear waste package materials testing report: basaltic and tuffaceous environments

    International Nuclear Information System (INIS)

    The disposal of high-level nuclear wastes in underground repositories in the continental United States requires the development of a waste package that will contain radionuclides for a time period commensurate with performance criteria, which may be up to 1000 years. This report addresses materials testing in support of a waste package for a basalt (Hanford, Washington) or a tuff (Nevada Test Site) repository. The materials investigated in this testing effort were: sodium and calcium bentonites and mixtures with sand or basalt as a backfill; iron and titanium-based alloys as structural barriers; and borosilicate waste glass PNL 76-68 as a waste form. The testing also incorporated site-specific rock media and ground waters: Reference Umtanum Entablature-1 basalt and reference basalt ground water, Bullfrog tuff and NTS J-13 well water. The results of the testing are discussed in four major categories: Backfill Materials: emphasizing water migration, radionuclide migration, physical property and long-term stability studies. Structural Barriers: emphasizing uniform corrosion, irradiation-corrosion, and environmental-mechanical testing. Waste Form Release Characteristics: emphasizing ground water, sample surface area/solution volume ratio, and gamma radiolysis effects. Component Compatibility: emphasizing solution/rock, glass/rock, glass/structural barrier, and glass/backfill interaction tests. This area also includes sensitivity testing to determine primary parameters to be studied, and the results of systems tests where more than two waste package components were combined during a single test

  20. Prospects for coupled modelling

    Energy Technology Data Exchange (ETDEWEB)

    Savage, D.

    2012-07-01

    Clay-based buffer and tunnel backfill materials are important barriers in the KBS- 3 repository concept for final disposal of spent nuclear fuel in Finland. Significant changes can be expected to occur to the properties and behaviour of buffer and backfill, especially during re-saturation and through the thermal period. Reactions will occur in response to thermal and chemical gradients, induced by the thermal output of the spent fuel and at interfaces between different barrier materials, such as cement/clay, steel/clay etc. Processes of ion exchange, mineral dissolution and precipitation, and swelling can lead to significant re-distribution of mass and evolution of physical properties so that reliable predictive modelling of future behaviour and properties must be made. This report evaluates the current status of modelling of buffer and backfill evolution and tries to assess the potential future capabilities in the short- to medium-term (5-10 years) in a number of technical areas: (1) Non-isothermal (T-H-M-C-B) modelling and the potential for cementation, (2) The consistency of models, (3) Swelling pressure, (4) Cement-bentonite interactions, (5) Iron-bentonite interactions, (6) Mechanical (shear) behavior, and (7) Bentonite erosion.

  1. Review of sorption and diffusion parameters for TVO-92

    International Nuclear Information System (INIS)

    Teollisuuden Voima Oy (TVO) is investigating the feasibility to dispose of spent nuclear fuel in a final repository constructed in a crystalline rock formation several hundred meters underground. This work is a part of the program of the updated preliminary safety assessment TVO-92. According to the plans the spent fuel, sealed in copper-iron canisters, is emplaced in drillholes below the tunnel floor and surrounded by bentonite clay buffer. The tunnels are backfilled with a mixture of quartz sand (90%) and bentonite (10%). Migration of solutes is retarded by sorption in the backfill and on fracture surfaces of the rocks and by diffusion into fissures and micropores of the rock. In migration calculations retardation due to sorption is derived from distribution ratios of solutes between water and solid. Migration by diffusion in rock is described by diffusion coefficients. Proposals are made for distribution ratios and diffusion coefficients in the backfill and in rocks for the radionuclides of spent significant with respect to safety of the final disposal. The proposals include realistic values besides the conservative values, leading with a high probability to overestimation of radiation doses in the biosphere. (orig.)

  2. R and D activities for ultimate disposal of HTR spent fuel elements

    International Nuclear Information System (INIS)

    For the direct ultimate disposal of HTR spent fuel, the LWR MAW storage method is examined, with a view to the following aspects: Activity released under rock pressure, and data of the design basis accidents: drop of waste package, underground fire, and inflow of lye in the post-operational phase of the repository. Strength tests with model packages containing HTR spent fuel in loose packing, or backfilled, have shown that backfilling with cement mortar or sand prevents damage to the spent fuel caused by rock pressure. Particle cracking in damaged, not backfilled fuel elements was at a maximum of 1 p.c. In leaching experiments with spent, complete fuel elements (900C - 2000C and 130/300 bar) only contaminations of the graphite matrix were released. Nuclide release after some 100 days of leaching time is determined by diffusion processes, but even after 1250 days of leaching, only trace amounts of Cs, Sr, Ce, Ba, Eu, Co, actinides or heavy metals could be found. High burn-up UO2 fuel kernels without coating and graphite matrix under the effects of leaching at 900C, 130 bar already after 60 days exhibited strong corrosion damage, and after about 100 days, cesium was released almost completely. (orig.)

  3. Waste-filling in fully-mechanized coal mining and its application

    Institute of Scientific and Technical Information of China (English)

    MIAO Xie-xing; ZHANG Ji-xiong; FENG Mei-mei

    2008-01-01

    A fully-mechanized coal mining (FMCM) technology capable of filling up the goaf with wastes (including solid wastes)is described. Industrial tests have proved that by using this technology not only can waste be re-used but also coal resources can be exploited with a higher recovery rate without removing buildings located over the working faces. Two special devices, a hydraulic support and a scraper conveyor, run side-by-side on the same working face to simultaneously realize mining and filling. These are described in detail. The tests allow analysis of rock pressure and ground subsidence when backfilling techniques are employed.These values are compared to those from mining without using backfilling techniques, under the same geological conditions. The concept of equivalent mining height is proposed based on theoretical analysis of rock pressure and ground subsidence. The upper limits of the rock pressure and ground subsidence can be estimated in backfilling mining using this concept along with traditional engineering formulae.

  4. CORALUS phase II. Gas release and migration in the boom clay of mol within the project 'Corrosion of Active Glass in the Underground conditions'

    International Nuclear Information System (INIS)

    Within the scope of national and international radioactive waste disposal concepts, the intention is to isolate them in deep geological formations in order to avoid the release of radionuclides into the biosphere above an acceptable limit. Besides salt and granite, clay formations are investigated. For investigating the suitability of clay formations in terms of their physical and chemical behaviour, the Belgian research centre SCK-CEN is performing an in situ test called CORALUS (CORrosion of Active gLass in Underground Storage conditions) in the Boom clay of the Underground Research Facility HADES in Mol /VAL 97/. The overall objective of the CORALUS project is to study the performance of both active and inactive HLW glass specimens in direct contact with different types of backfill materials under conditions as representative as possible for those expected to prevail in a disposal site in the Boom clay formation (α- and γ-irradiation, temperature, pressure, backfill material, formation water,..). The experimental set-up represents a scenario in which the vitrified waste comes into direct contact with the interacting backfill material and/or the Boom clay. (orig.)

  5. Gas release and migration in the boom clay of mol within the project 'Corrosion of Active Glass in the Underground conditions' (CORALUS)

    International Nuclear Information System (INIS)

    Within the scope of national and international radioactive waste disposal concepts, the intention is to dispose of radioactive waste in deep geological formations, in order to isolate them from the biosphere and avoid the release of radionuclides above an acceptable limit. Besides salt and granite, clay formations are investigated. For investigating the suitability of clay formations in terms of their physical and chemical behaviour, the Belgian research centre SCK-CEN is performing an in situ test called CORALUS (CORrosion of Active gLass in Underground Storage conditions) in the Boom clay of the Underground Research Facility HADES in Mol/VAL 97/. The overall objective of the CORALUS project is to study the performance of both active and inactive HLW glass specimens in direct contact with different types of backfill materials under conditions as representative as possible for those expected to prevail in a disposal site in the Boom clay formation (α- and γ-irradiation, temperature, pressure, backfill material, formation water,..). The experimental set-up represents a scenario in which the vitrified waste comes into direct contact with the interacting backfill material and/or the Boom clay, because of the occurrence of fissures in the waste canisters and the metallic overpack. (orig.)

  6. Redox-filled Carbon-Fiber Microelectrodes for Single-Cell Exocytosis

    Science.gov (United States)

    Cox, Jonathan T.; Gunderson, Christopher G.; Zhang, Bo

    2014-01-01

    Carbon-fiber microelectrodes (CFEs) are the primary electroanalytical tool in single-cell exocytosis and in-vivo studies. Here we report a new study on the kinetic properties of electrolyte-filled CFEs in single-cell measurements and demonstrate that the addition of outer sphere redox species, such as Fe(CN)63− and Ru(NH3)63+, in the backfill electrolyte solution can greatly enhance the kinetic response of CFEs. We show that at 750 mV, a voltage normally applied for detection of dopamine, the presence of fast outer sphere redox species in the backfilling solution significantly enhances the kinetic response of CFEs toward fast dopamine detection at single PC12 cells. Moreover, we also demonstrate that the use of Fe(CN)63− in the backfilling solution has enabled direct measurement of dopamine at applied voltages as low as 200 mV. This kinetic enhancement is believed to be due to faster electron-transfer kinetics on the coupling pole as compared to the sluggish reduction of oxygen. We anticipate that such redox-filled CFE ultramicroelectrodes will find many useful applications in single cell exocytosis and in-vivo sensing. PMID:24833889

  7. Geoelectric monitoring of bentonite barrier resaturation in the Aespoeprototype repository. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wieczorek, Klaus; Komischke, Michael; Miehe, Ruediger; Moog, Helge

    2014-10-15

    In 1994, SKB started constructing the ''Prototype Repository'', a full-scale replica of a part of a future KBS-3 repository in crystalline rock, at the AespoeHard Rock Laboratory. Six emplacement boreholes were planned and constructed in two tunnel sections until end of 1999. The international EC co-funded Prototype Repository project was started in 2000 (contract FIKW-CT-2000-00055). The project partners were SKB (Sweden), POSIVA (Finland), ENRESA (Spain), GRS (Germany), BGR (Germany), UWC (UK), and JNC (Japan). Between 2000 and 2003 the complete Prototype Repository was equipped and instrumented, and monitoring was started. In February 2004 the EC funding expired. The Prototype Repository project was continued with national funding of the project partners. In 2011, dismantling of Section II was started in a three-year project. Backfill, buffer and canisters as well as part of the instrumentation were retrieved, and numerous laboratory investigations on buffer and backfill samples were performed. GRS' part in the Prototype Repository was the monitoring of backfill and buffer resaturation using geoelectric tomography. The measurements were completed in 2013.

  8. Modeling radon entry into Florida slab-on-grade houses.

    Science.gov (United States)

    Revzan, K L; Fisk, W J; Sextro, R G

    1993-10-01

    Radon entry into a Florida house whose concrete slab is supported by a permeable concrete-block stem wall and a concrete footer is modeled. The slab rests on backfill material; the same material is used to fill the footer trench. A region of undisturbed soil is assumed to extend 10 m beyond and below the footer. The soil is assumed homogeneous and isotropic except for certain simulations in which soil layers of high permeability or radium content are introduced. Depressurization of the house induces a pressure field in the soil and backfill. The Laplace equation, resulting from Darcy's law and the continuity equation, is solved using a steady-state finite-difference model to determine this field. The mass-transport equation is then solved to obtain the diffusive and advective radon entry rates through the slab; the permeable stem wall; gaps at the intersections of the slab, stem wall, and footer; and gaps in the slab. These rates are determined for variable soil, backfill, and stem-wall permeability and radium content, slab-opening width and position, slab and stem-wall diffusivity, and water table depth. The variations in soil permeability and radium content include cases of horizontally stratified soil. We also consider the effect of a gap between the edge of the slab and the stem wall that restricts the passage of soil gas from the stem wall into the house. Calculations indicate that the total radon entry rate is relatively low unless the soil or backfill permeability or radium content is high. Variations in most of the factors, other than the soil permeability and radium content, have only a small effect on the total radon entry rate. However, for a fixed soil permeability, the total radon entry rate may be reduced by a factor of 2 or more by decreasing the backfill permeability, by making the stem wall impermeable and gap-free, (possibly by constructing a one-piece slab/stem-wall/footer), or by increasing the pressure in the interior of the stem wall (by

  9. Long-Term Modeling of Coupled Processes in a Generic Salt Repository for Heat-Generating Nuclear Waste: Analysis of the Impacts of Halite Solubility Constraints

    Science.gov (United States)

    Blanco Martin, L.; Rutqvist, J.; Battistelli, A.; Birkholzer, J. T.

    2015-12-01

    Rock salt is a potential medium for the underground disposal of nuclear waste because it has several assets, such as its ability to creep and heal fractures and its water and gas tightness in the undisturbed state. In this research, we focus on disposal of heat-generating nuclear waste and we consider a generic salt repository with in-drift emplacement of waste packages and crushed salt backfill. As the natural salt creeps, the crushed salt backfill gets progressively compacted and an engineered barrier system is subsequently created [1]. The safety requirements for such a repository impose that long time scales be considered, during which the integrity of the natural and engineered barriers have to be demonstrated. In order to evaluate this long-term integrity, we perform numerical modeling based on state-of-the-art knowledge. Here, we analyze the impacts of halite dissolution and precipitation within the backfill and the host rock. For this purpose, we use an enhanced equation-of-state module of TOUGH2 that properly includes temperature-dependent solubility constraints [2]. We perform coupled thermal-hydraulic-mechanical modeling and we investigate the influence of the mentioned impacts. The TOUGH-FLAC simulator, adapted for large strains and creep, is used [3]. In order to quantify the importance of salt dissolution and precipitation on the effective porosity, permeability, pore pressure, temperature and stress field, we compare numerical results that include or disregard fluids of variable salinity. The sensitivity of the results to some parameters, such as the initial saturation within the backfill, is also addressed. References: [1] Bechthold, W. et al. Backfilling and Sealing of Underground Repositories for Radioactive Waste in Salt (BAMBUS II Project). Report EUR20621 EN: European Atomic Energy Community, 2004. [2] Battistelli A. Improving the treatment of saline brines in EWASG for the simulation of hydrothermal systems. Proceedings, TOUGH Symposium 2012

  10. Challenges in planning and performing the retrieval of the prototype repository at Aespoe HRL- Project management's reflections and practical experiences from field work

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Since 2001 the Prototype Repository at Aespoe Hard Rock Laboratory has been carried out as a large-scale experimental installation of the KBS-3 Swedish/Finnish concept for final disposal of spent nuclear fuel. The overall objective of the trial 'Prototype Repository' is to test and demonstrate the integrated function of sub-components in a final repository under realistic full-scale conditions. Data from the experiment shall also be compared to results from modelling based on site conditions. Opening of the outer section for the Prototype Repository was recognized as substantial operation. No trial of this size has been made earlier with regard to removal of buffer and backfilling. Experience was available only from retrieval of the buffer in Canister Retrieval Test at Aespoe HRL where samples of the buffer were taken, down to the mid-height of the canister. It was expected that sampling of the buffer in the deposition holes of the Prototype Repository would be very difficult, especially deep down in the holes. No significant experience regarding the breaching of such a concrete plug or removing backfill was available. The lack of experience together with the size of the project made extensive planning essential before the opening and removal could begin. It was decided that SKB (Sweden) and Posiva Oy (Finland) should run the project in a co-operation, where SKB is responsible for managing the project. In addition, a wide international interest was observed and accordingly waste management organisations were invited by SKB and Posiva to be a party to the Retrieval of the Prototype Repository. Six individual project agreements were signed with Andra (France), NUMO (Japan), NDA (United Kingdom), NAGRA (Switzerland), BMWi (Germany) and NWMO (Canada). The planning of the Retrieval of the Prototype Repository (section II) started at the beginning of 2010. The planning phase was successful meaning that the breaching of

  11. Experimental programme to demonstrate the viability of the supercontainer concept for HLW

    International Nuclear Information System (INIS)

    The EIG EURIDICE (a joint venture between the Belgian Organisation for Radioactive Waste Management - ONDRAF/NIRAS - and the Belgian Nuclear Research Centre - SCKoCEN) is responsible for performing large-scale tests, technical demonstrations and experiments to assess the feasibility of a final disposal of vitrified radioactive waste in deep clay layers. This is part of the Belgian Research and Development programme managed by ONDRAF/NIRAS. The current Belgian reference design for vitrified HLW and spent fuel assemblies is the so-called Supercontainer design. The vitrified waste canisters or spent fuel assemblies are enclosed in a carbon steel overpack which has to prevent contact between water from the host formation and the waste during the thermal phase. In order to maintain favourable chemical conditions to avoid corrosion during this period (several hundred or even thousand of years), the overpack is surrounded by a high alkaline concrete buffer of about 70 cm thick. The buffer also provides permanent radiological shielding for the workers, simplifying handling and other operations. All the components of the Supercontainer are constructed in above ground installations, thus creating favourable QA/QC conditions. After the emplacement of the Supercontainers in the disposal galleries, the remaining space will be backfilled. Tests to demonstrate the viability and the construction feasibility of the supercontainer design have been initiated. The viability programme includes Tests to verify the feasibility to construct and emplace the components of the supercontainers, and tests to verify the feasibility to backfill the disposal galleries once the supercontainers are placed. Supercontainer construction: Tests in column to verify the construction feasibility (risk of cracking) of the buffer with two different types of concrete (a self-compacting concrete - SCC - and a rheoplastic concrete RPC) were performed in collaboration with the Belgian concrete factory Socea. A

  12. COBRA-SFS [Spent-Fuel Storage] thermal-hydraulic analyses of the CASTOR-1C and REA 2023 BWR storage casks containing consolidated spent fuel

    International Nuclear Information System (INIS)

    Consolidation of spent nuclear fuel rods is being considered as one option for more efficient and compact storage of reactor spent fuel assemblies. In this concept, rods from two disassembled spent fuel assemblies will be consolidated in a space originally intended to store a single unconsolidated assembly. The thermal performance of consolidated fuel rods in dry storage, especially in multiassembly storage systems, is one of the major issues that must be addressed prior to implementation. In this study, Pacific Northwest Laboratory researchers performed thermal-hydraulic analyses for both the REA 2023 cask and the CASTOR-1C cask containing either unconsolidated or consolidated BWR spent fuel assemblies. The objective was to determine the effect of consolidating spent fuel assemblies on the temperature distributions within both types of casks. Two major conclusions resulted from this study. First, a lumping technique (combining rods and flow channels), which reduces the number of computational nodes required to model complex multiassembly geometries, could be used for both unconsolidated and consolidated rods with negligible effect on prediction accuracies. Second, with a relatively high thermal conductivity backfill gas (e.g., helium), the predicted peak fuel rod temperature in a canister of consolidated rods generating the same amount of heat as an unconsolidated assembly is essentially the same as the peak temperature in the unconsolidated assembly. In contrast, with a relatively low thermal conductivity backfill gas (e.g., nitrogen), the opposite is true and the predicted peak temperature in a consolidated canister is significantly higher than in an unconsolidated assembly. Therefore, when rods are consolidated, selection of the backfill gas is important in maintaining peak rod temperatures below allowable values for rods with relatively high decay heat generation rates

  13. Waste Isolation Pilot Plant simulated RH TRU waste experiments: Data and interpretation pilot

    International Nuclear Information System (INIS)

    The simulated, i.e., nonradioactive remote-handled transuranic waste (RH TRU) experiments being conducted underground in the Waste Isolation Pilot Plant (WIPP) were emplaced in mid-1986 and have been in heated test operation since 9/23/86. These experiments involve the in situ, waste package performance testing of eight full-size, reference RH TRU containers emplaced in horizontal, unlined test holes in the rock salt ribs (walls) of WIPP Room T. All of the test containers have internal electrical heaters; four of the test emplacements were filled with bentonite and silica sand backfill materials. We designed test conditions to be ''near-reference'' with respect to anticipated thermal outputs of RH TRU canisters and their geometrical spacing or layout in WIPP repository rooms, with RH TRU waste reference conditions current as of the start date of this test program. We also conducted some thermal overtest evaluations. This paper provides a: detailed test overview; comprehensive data update for the first 5 years of test operations; summary of experiment observations; initial data interpretations; and, several status; experimental objectives -- how these tests support WIPP TRU waste acceptance, performance assessment studies, underground operations, and the overall WIPP mission; and, in situ performance evaluations of RH TRU waste package materials plus design details and options. We provide instrument data and results for in situ waste container and borehole temperatures, pressures exerted on test containers through the backfill materials, and vertical and horizontal borehole-closure measurements and rates. The effects of heat on borehole closure, fracturing, and near-field materials (metals, backfills, rock salt, and intruding brine) interactions were closely monitored and are summarized, as are assorted test observations. Predictive 3-dimensional thermal and structural modeling studies of borehole and room closures and temperature fields were also performed

  14. Field lysimeter studies for performance evaluation of grouted Hanford defense wastes

    Energy Technology Data Exchange (ETDEWEB)

    Last, G.V.; Serne, R.J.; LeGore, V.L.

    1995-02-01

    The Grout Waste Test Facility (GWTF) consisted of four large field lysimeters designed to test the leaching and migration rates of grout-solidified low-level radioactive wastes generated by Hanford Site operations. Each lysimeter was an 8-m-deep by 2-media closed-bottom caisson that was placed in the ground such that the uppermost rim remained just above grade. Two of these lysimeters were used; the other two remained empty. The two lysimeters that were used (A-1 and B-1) were backfilled with a two-layer soil profile representative of the proposed grout disposal site. The proposed grout disposal site (termed the Grout Treatment Facility Landfill) is located immediately east of the Hanford Site`s 200 East Area. This soil profile consisted of a coarse sand into which the grout waste forms were placed and covered by 4 m of a very fine sand. The A-1 lysimeter was backfilled in March 1985, with a grout-solidified phosphate/sulfate liquid waste from N Reactor decontamination and ion exchange resin regeneration. The B-1 lysimeter was backfilled in September 1985 and received a grout-solidified simulated cladding removal waste representative of waste generated from fuel reprocessing operations at the head end of the Plutonium Uranium Extraction (PUREX) plant. Routine monitoring and leachate collection activities were conducted for over three years, terminating in January 1989. Drainage was collected sporadically between January 1989 and December 1992. Decontamination and decommissioning of these lysimeters during the summer of 1994, confirmed the presence of a 15 to 20-cm-long hairline crack in one of the bottom plate welds. This report discusses the design and construction of the GWTF, presents the routine data collected from this facility through January 1989 and subsequent data collected sporadically between 1989 and 1993, and provides a brief discussion concerning preliminary interpretation of the results.

  15. Buffer mass test - Rock drilling and civil engineering

    International Nuclear Information System (INIS)

    The buffer mass test (BMT) is being run in the former 'ventilation drift' in which a number of rock investigations were previously conducted. A number of vertical pilot holes were drilled from the tunnel floor to get information of the water inflow in possible heater hole position. The final decision of the location of the heater holes was then made, the main principle being that much water should be available in each hole with the possible exception of one of the holes. Thereafter, the diameter 0.76 m heater holes were drilled to a depth of 3-3.3 m. Additional holes were then drilled for rock anchoring of the lids of the four outer heater holes, for the rock mechanical investigation, as well as for a number of water pressure gauges. The inner, about 12 m long part of the tunnel, was separated from the outer by bulwark. The purpose of this construction was to confine a backfill, the requirements of the bulwark being to withstand the swelling pressure as well as the water pressure. Outside the bulwark an approximately 1.5-1.7 m thick concrete slab was cast on the tunnel floor, extending about 24.7 m from the bulwark. Boxing-outs with the same height as the slab and with the horizontal dimensions 1.8 x 1.8 m, were made and rock-anchored concrete lids were cast on top of them after backfilling. The slab which thus represents 'rock', also forms a basal support of the bulwark. The lids permits access to the backfill as well as to the underlying, highly compacted bentonite for rapid direct determination of the water distributin at the intended successive test stops. The construction of the slab and lids will be described in this report. (Author)

  16. Systems study on engineered barriers: barrier performance analysis

    International Nuclear Information System (INIS)

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed

  17. Single PWR spent fuel assembly heat transfer data for computer code evaluations

    International Nuclear Information System (INIS)

    The descriptions and results of two separate heat transfer tests designed to investigate the dry storage of commercial PWR spent fuel assemblies are presented. Presented first are descriptions and selected results from the Fuel Temperature Test performed at the Engine Maintenance and Disassembly facility on the Nevada Test Site. An actual spent fuel assembly from the Turkey Point Unit Number 3 Reactor with a decay heat level of 1.17 KW, was installed vertically in a test stand mounted canister/liner assembly. The boundary temperatures were controlled and the canister backfill gases were alternated between air, helium and vacuum to investigate the primary heat transfer mechanisms of convection, conduction and radiation. The assembly temperature profiles were experimentally measured using installed thermocouple instrumentation. Also presented are the results from the Single Assembly Heat Transfer Test designed and fabricated by Allied General Nuclear Services, under contract to the Department of Energy, and ultimately conducted by the Pacific Northwest Laboratory. For this test, an electrically heated 15 x 15 rod assembly was used to model a single PWR spent fuel assembly. The electrically heated model fuel assembly permitted various ''decay heat'', levels to be tested; 1.0 KW and 0.5 KW were used for these tests. The model fuel assembly was positioned within a prototypic fuel tube and in turn placed within a double-walled sealed cask. The complete test assembly could be positioned at any desired orientation (horizontal, vertical, and 250 from horizontal for the present work) and backfilled as desired (air, helium, or vacuum). Tests were run for all combinations of ''decay heat,'' backfill, and orientation. Boundary conditions were imposed by temperature controlled guard heaters installed on the cask exterior surface

  18. Mineralogy and sealing properties of various bentonites and smectite-rich clay materials

    International Nuclear Information System (INIS)

    The present work includes a coherent study of Wyoming bentonite with respect to the most relevant properties for use in a repository, and a parallel study of other potential buffer and tunnel backfilling materials. The reason for this is twofold; to quantify the effect of mineralogical variations on the various important sealing properties of bentonite, and to verify that there are alternative potential sources of bentonite. The latter is motivated by the fact that Sweden alone plans to deposit at least 6,000 copper canisters which include approximately 130,000 metric tones bentonite buffer material and several times more as tunnel backfill material. Different types of sealing clay materials may also be relevant to use, since the demands on the clay will be different at the various locations in a repository. Alternative sources of bentonite would consequently be valuable in order to secure quality, supply, and price. Important aspects on buffer and tunnel backfilling materials may be summarized as: Original sealing properties. Hazardous substances in any respect. Short-term effects of ground-water chemistry. Long-term stability, i.e. effects of temperature and ground-water chemistry. Availability. Costs. The focus in this study is on the first three items. The long-term stability is indirectly considered in that mineralogical composition is determined. The availability is only considered in such a way that most of the analyzed materials represent huge clay formations, which contain much more material than needed for a repository. The cost aspects have not been included, mainly because the present day price is not relevant due to the time frame of the construction of a repository

  19. Mineralogy and sealing properties of various bentonites and smectite-rich clay materials

    Energy Technology Data Exchange (ETDEWEB)

    Karnland, Ola; Olsson, Siv; Nilsson, Ulf (Clay Technology AB (SE))

    2006-12-15

    The present work includes a coherent study of Wyoming bentonite with respect to the most relevant properties for use in a repository, and a parallel study of other potential buffer and tunnel backfilling materials. The reason for this is twofold; to quantify the effect of mineralogical variations on the various important sealing properties of bentonite, and to verify that there are alternative potential sources of bentonite. The latter is motivated by the fact that Sweden alone plans to deposit at least 6,000 copper canisters which include approximately 130,000 metric tones bentonite buffer material and several times more as tunnel backfill material. Different types of sealing clay materials may also be relevant to use, since the demands on the clay will be different at the various locations in a repository. Alternative sources of bentonite would consequently be valuable in order to secure quality, supply, and price. Important aspects on buffer and tunnel backfilling materials may be summarized as: Original sealing properties. Hazardous substances in any respect. Short-term effects of ground-water chemistry. Long-term stability, i.e. effects of temperature and ground-water chemistry. Availability. Costs. The focus in this study is on the first three items. The long-term stability is indirectly considered in that mineralogical composition is determined. The availability is only considered in such a way that most of the analyzed materials represent huge clay formations, which contain much more material than needed for a repository. The cost aspects have not been included, mainly because the present day price is not relevant due to the time frame of the construction of a repository

  20. The design of a large scale heater test in boom clay - the Praclay experiments

    International Nuclear Information System (INIS)

    PRACLAY aims to demonstrate the suitability of the Boom Clay host rock, in terms of performance of the disposal, to undergo the thermal load induced by the vitrified HI. PRACLAY represents an important milestone for the Safety and Feasibility Cases 1 (2013) and II (2020). PRACLAY is developed to be design-independent to overcome possible future changes in the design. The temperature criterion is: The maximum temperature in clay-based backfill materials, used as engineered barriers, for heat producing radioactive waste, must be kept below 100 C. PRACLAY regroups a set of four experiments. The PRACLAY Crossing consists in the intersection of the connecting gallery and the PRACLAY gallery, and aims to demonstrate that it is possible to construct a crossing between an access gallery and a disposal gallery at an acceptable cost and limiting the perturbation in the host-rock. The PRACLAY Heater Test has to demonstrate that Boom Clay will behave as predicted under a thermal load. The PRACLAY Plug Test is aimed at demonstrating that it is possible to cut-off hydraulically the Excavation Damaged Zone (EDZ) and the engineered barriers of the disposal galleries with a horizontal plug. 4. The PRACLAY backfill test aims to test the installation and the performance of different types of backfill or buffer material (cement, slaked lime, bentonite, Boom Clay...) that could be considered in the design of disposal galleries. The paper will present the objectives, the preliminary model predictions, and, as a result of these, the design of the test, including the monitoring plan and the choices regarding the boundary and initial conditions. (authors)

  1. Field lysimeter studies for performance evaluation of grouted Hanford defense wastes

    International Nuclear Information System (INIS)

    The Grout Waste Test Facility (GWTF) consisted of four large field lysimeters designed to test the leaching and migration rates of grout-solidified low-level radioactive wastes generated by Hanford Site operations. Each lysimeter was an 8-m-deep by 2-media closed-bottom caisson that was placed in the ground such that the uppermost rim remained just above grade. Two of these lysimeters were used; the other two remained empty. The two lysimeters that were used (A-1 and B-1) were backfilled with a two-layer soil profile representative of the proposed grout disposal site. The proposed grout disposal site (termed the Grout Treatment Facility Landfill) is located immediately east of the Hanford Site's 200 East Area. This soil profile consisted of a coarse sand into which the grout waste forms were placed and covered by 4 m of a very fine sand. The A-1 lysimeter was backfilled in March 1985, with a grout-solidified phosphate/sulfate liquid waste from N Reactor decontamination and ion exchange resin regeneration. The B-1 lysimeter was backfilled in September 1985 and received a grout-solidified simulated cladding removal waste representative of waste generated from fuel reprocessing operations at the head end of the Plutonium Uranium Extraction (PUREX) plant. Routine monitoring and leachate collection activities were conducted for over three years, terminating in January 1989. Drainage was collected sporadically between January 1989 and December 1992. Decontamination and decommissioning of these lysimeters during the summer of 1994, confirmed the presence of a 15 to 20-cm-long hairline crack in one of the bottom plate welds. This report discusses the design and construction of the GWTF, presents the routine data collected from this facility through January 1989 and subsequent data collected sporadically between 1989 and 1993, and provides a brief discussion concerning preliminary interpretation of the results

  2. The Canadian nuclear fuel waste management program

    International Nuclear Information System (INIS)

    An overview is presented of the status of the research and development program, under rsponsibility of the Atomic Energy of Canada Limited (AECL), for assessing the concept of nuclear fuel waste disposal deep in plutonic rock of the Canadian Shield. A passive multi-barrier concept has been adopted for disposal that combines the containment provided by the structural, hydraulic and geochemical characteristics of the rock mass with a series of engineered barriers. The conceptual disposal vault consists of an array of disposal rooms excavated in plutonic rock at a depth between 500 and 1000 m. Prior to disposal, the waste would be placed in cylindrical containers surrounded by a buffer, which is a mixture of bentonite cla and sand. The rooms would be backfilled with mixture of clay, and crushed granite or san. Bulkheads would seal the entrances. Closure would be achieved by backfilling the access tunnels in the same manner as the rooms and than backfilling the shafts with compacted clay and crushed granite separated by a series of supporting bulkheads. Very preliminary results from the case study indicate that the good rock provides the most effective barrier to movement of radionuclides to the surface. The most significant pathways through the geosphere involve diffusion through the good rock to the major fracture intersecting the vault, convection upward along the fracture, and discharge either at topographic lows or through a domestic water supply well used by the critical group. Long-lived non-sorbing radionuclides, available in the gaps between the fuel pellets and the fuel cladding or at the grain boundaries, contribute most to the radiological dose. With appropriate constraints on the location of the waste packages relative to the major fracture zones, radiological risk is expected to satisfy the regulatory criteria. (H.W.) 5 figs

  3. Closure and Sealing Design Calculation

    International Nuclear Information System (INIS)

    The purpose of the ''Closure and Sealing Design Calculation'' is to illustrate closure and sealing methods for sealing shafts, ramps, and identify boreholes that require sealing in order to limit the potential of water infiltration. In addition, this calculation will provide a description of the magma that can reduce the consequences of an igneous event intersecting the repository. This calculation will also include a listing of the project requirements related to closure and sealing. The scope of this calculation is to: summarize applicable project requirements and codes relating to backfilling nonemplacement openings, removal of uncommitted materials from the subsurface, installation of drip shields, and erecting monuments; compile an inventory of boreholes that are found in the area of the subsurface repository; describe the magma bulkhead feature and location; and include figures for the proposed shaft and ramp seals. The objective of this calculation is to: categorize the boreholes for sealing by depth and proximity to the subsurface repository; develop drawing figures which show the location and geometry for the magma bulkhead; include the shaft seal figures and a proposed construction sequence; and include the ramp seal figure and a proposed construction sequence. The intent of this closure and sealing calculation is to support the License Application by providing a description of the closure and sealing methods for the Safety Analysis Report. The closure and sealing calculation will also provide input for Post Closure Activities by describing the location of the magma bulkhead. This calculation is limited to describing the final configuration of the sealing and backfill systems for the underground area. The methods and procedures used to place the backfill and remove uncommitted materials (such as concrete) from the repository and detailed design of the magma bulkhead will be the subject of separate analyses or calculations. Post-closure monitoring will not

  4. Cost effects of Cu powder and bentonite on the disposal costs of an HLW repository in

    International Nuclear Information System (INIS)

    This paper provides the cost effect results of Cu powder and bentonite on the disposal cost for an HLW repository in Korea. In the cost analysis for both of these cost drivers, the price of Cu powder and the bentonite can affect the canister cost and the bentonite cost of the disposal holes as well as backfilling cost of the tunnels, respectively. Finally, we found that the unit cost of Cu and bentonite was the dominant cost drivers for the surface and underground facilities of an HLW repository. Therefore, an optimization of a canister and the layout of a disposal hole and disposal tunnels are essential to decrease the direct disposal cost of spent fuels. The disposal costs can be largely divided into two parts such as a surface facilities' cost and an underground facilities' cost. According to the KRS' cost analysis, the encapsulation material as well as the buffering and backfilling cost were the significant costs. Especially, a canister's cost was approximately estimated to be more than one fourth of the overall disposal costs. So it can be estimated that the unit cost of Cu powder is an important cost diver. Because the outer shell of the canister was made of Cu powder by a cold spray coating method. In addition, the unit cost of bentonite can also affect the buffering and the backfilling costs of the disposal holes and the disposal tunnels. But, these material costs will be highly expensive and unstable due to the modernization of the developing countries. So the studies for a material cost should be continued to identify the actual cost of an HLW repository

  5. Systems study on engineered barriers: barrier performance analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stula, R.T.; Albert, T.E.; Kirstein, B.E.; Lester, D.H.

    1980-09-01

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed.

  6. Closure and Sealing Design Calculation

    Energy Technology Data Exchange (ETDEWEB)

    T. Lahnalampi; J. Case

    2005-08-26

    The purpose of the ''Closure and Sealing Design Calculation'' is to illustrate closure and sealing methods for sealing shafts, ramps, and identify boreholes that require sealing in order to limit the potential of water infiltration. In addition, this calculation will provide a description of the magma that can reduce the consequences of an igneous event intersecting the repository. This calculation will also include a listing of the project requirements related to closure and sealing. The scope of this calculation is to: summarize applicable project requirements and codes relating to backfilling nonemplacement openings, removal of uncommitted materials from the subsurface, installation of drip shields, and erecting monuments; compile an inventory of boreholes that are found in the area of the subsurface repository; describe the magma bulkhead feature and location; and include figures for the proposed shaft and ramp seals. The objective of this calculation is to: categorize the boreholes for sealing by depth and proximity to the subsurface repository; develop drawing figures which show the location and geometry for the magma bulkhead; include the shaft seal figures and a proposed construction sequence; and include the ramp seal figure and a proposed construction sequence. The intent of this closure and sealing calculation is to support the License Application by providing a description of the closure and sealing methods for the Safety Analysis Report. The closure and sealing calculation will also provide input for Post Closure Activities by describing the location of the magma bulkhead. This calculation is limited to describing the final configuration of the sealing and backfill systems for the underground area. The methods and procedures used to place the backfill and remove uncommitted materials (such as concrete) from the repository and detailed design of the magma bulkhead will be the subject of separate analyses or calculations. Post

  7. Vault sealing research and development for the Canadian nuclear fuel waste management program

    International Nuclear Information System (INIS)

    The major research and development activities in the disposal vault sealing program are buffer development, backfill development, grouting, tunnel and shaft sealing development, and borehole sealing development. The buffer is likely to be a mixture of clay and sand surrounding the waste package and is intended, primarily, to minimize near-field mass transport. The backfill would fill the remainder of the underground workings and most of the volume of the access shafts. Its major component would be crushed rock or sand, or both, with sufficient clay added to achieve the required permeability specification. Boreholes would be sealed throughout their length with low-permeability materials. These may be cements or clays. Shaft seals would be emplaced at specific locations and, probably, would be composed of a low-permeability clay or concrete plug, together with grouting of the rock surrounding the plug. Progress to date and planned future activities for each major part of the program are described. The principal foci of the program are the research and development activities required to assess the concept of underground disposal in plutonic rock and the design and implementation of vault sealing experiments in the Underground Research Laboratory. Program plans are presented that describe the logical progression of each major component of the program, and that indicate the timing of major events that contribute to the final objective of the program, which is to develop engineering specifications for the buffer, backfill and seals, and to justify these specifications in terms of the performance of the waste disposal system. 131 refs

  8. General strategy, clay based disposal concepts and integration (GSI)

    International Nuclear Information System (INIS)

    This session gathers 20 articles (posters) dealing with: the assessment of backfill materials and methods for deposition tunnels; HTV-1: a semi technical scale testing of a multi-layer hydraulic shaft sealing system; the development of water content adjust method by mixing powdered-ice and chilled bentonite: application to the construction of bentonite engineered barriers by shot-clay method; repository design issues related to the thermal impact induced by heat emitting radioactive waste; pillared clays, using Romanian montmorillonite; the simulation of differential settlements of clay based engineered barrier systems in a geo-centrifuge; the critical issues regarding clay behaviour in the KBS-3H repository design; an alternative buffer material experiment; assessing the performance of a swelling clay tunnel seal and issues identified in the course of its operation; the activation of a Ca-bentonite as buffer material; a large diameter borehole type repository in the clays for radioactive waste long term storage; the erosion of backfill materials during the installation phase; the behaviour of the clay cover of a site for very low level nuclear waste: field flexion tests; the laboratory tests made on three different backfill candidates for the Swedish KBS- 3V concept; the engineering geological clay research for radioactive waste repository in Slovakia; the ESDRED project, module 1 - Design, fabrication, assembly, handling and packaging of buffer rings; the laboratory experiments on the sealing ability of bentonite pellets; the screening of bentonite resources for use as an engineered barrier component in deep geologic repositories; the assessment of the radionuclide release from the near-field environment of a spent nuclear fuel geological repository; and the emplacement tests with granular bentonite

  9. Remaining Sites Verification Package for the 1607-D4 Septic System, Waste Site Reclassification Form 2005-036

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Carlson

    2006-02-23

    The 1607-D4 Septic System was a septic tank and tile field that received sanitary sewage from the 115-D/DR Gas Recirculation Facility. This septic system operated from 1944 to 1968. Decommissioning took place in 1985 and 1986 when all above-grade features were demolished and the tank backfilled. The results of verification sampling demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.

  10. Are geopolymers more suitable than Portland cement to produce high volume recycled aggregates HPC?

    OpenAIRE

    Torgal, Fernando Pacheco; Ding, Yining; Miraldo, Sérgio; Abdollahnejad, Zahra; J. A. Labrincha

    2012-01-01

    The 70% minimum construction and demolition wastes-C&DW recycling rate set by the Revised Waste framework Directive No. 2008/98/EC to be enforced beyond 2020, will increase the need of effective recycling methods in a dramatic manner. So far, recycled aggregates (which constitute the majority of C&DW) are reused in low volume percentages for average compressive strength concretes and mostly as road sub-base and back-fill material which, in turn, constitutes a down-cycling option. Most investi...

  11. Mitigation of Traffic-Induced Ground Vibration by Inclined Wave Barriers

    DEFF Research Database (Denmark)

    Andersen, Lars; Augustesen, Anders Hust

    2009-01-01

    capabilities of an open trench, lined by sheet pile walls, are compared to those of a barrier with the original soil between the walls or a trench closed by a lid at the top. To this purpose, a three-dimensional boundary-element/finite-element model has been developed, based on a formulation in a moving frame......Double sheet pile walls can be used as wave barriers in order to mitigate ground vibrations from railways. The present analysis concerns the efficiency of such barriers, especially with regard to the influence of the barrier inclination and the backfill between the walls. Thus, the screening...

  12. In the heart of rock; Au coeur de la roche

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-01-01

    This educational document gives a presentation of the Andra underground research laboratory of Bure (Haute-Marne and Meuse, France) devoted to the study of the underground disposal of radioactive wastes. The document is presented in the form of a comics. It describes the geological setting of the laboratory, located in the eastern edge of the Paris basin, the properties of the Callovian-Oxfordian clay layer, the digging of the boreholes and galleries, the mine-by test and its instrumentation, the backfilling and sealing of the galleries and the reversibility of the burial of radioactive waste containers. (J.S.)

  13. Direct methods of soil-structure interaction analysis for earthquake loadings (III)

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J. B.; Lee, S. R.; Kim, J. M.; Park, K. R.; Choi, J. S.; Oh, S. B. [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1995-06-15

    In this study, direct methods for seismic analysis of soil-structure interaction system have been studied. A computer program 'KIESSI-QK' has been developed based on the finite element technique coupled with infinite element formulation. A substructuring method isolating the displacement solution of near field soil region was adopted. The computer program developed was verified using a free-field site response problem. The post-correlation analysis for the forced vibration tests after backfill of the Hualien LSST project has been carried out. The seismic analyses for the Hualien and Lotung LSST structures have been also performed utilizing the developed computer program 'KIESSI-QK'.

  14. Direct methods of soil-structure interaction analysis for earthquake loadings (V)

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J. B.; Choi, J. S.; Lee, J. J.; Park, D. U. [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-07-15

    Methodologies of SSI analysis for earthquake loadings have been reviewed. Based on the finite method incorporating infinite element technique for the unbounded exterior region, a computer program for the nonlinear seismic analysis named as 'KIESSI' has been developed. The computer program has been verified using a free-field site-response problem. Post-correlation analysis for the Hualien FVT after backfill and the blind prediction of earthquake responses have been carried out utilizing the developed computer program. The earthquake response analyses for three LSST structures (Hualien, Lotung and Tepsco structure) have also been performed and compared with the measured data.

  15. Application of rock mechanics to cut-and-fill mining. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    1980-05-15

    The conference on application of rock mechanics to cut-and-fill mining was held June 1-3, 1980, at the University of Luleaa, Sweden. The papers in this volume deal almost entirely with the Naesliden project in Sweden. Stress measurements were made on the rock mass before and during mining and complex computer codes using the finite element method developed to calculate the strains and their changes as mining developed. Major problems involved the effects of joints and the mechanical properties of the hydraulic backfill and in corporating these items in the calculations. Most papers were entered individually into EDB. (LTN)

  16. Selected problems relating to the dynamics of block-type foundations for machines

    Directory of Open Access Journals (Sweden)

    Marek Zombroń

    2014-07-01

    Full Text Available Atypical but real practical problems relating to the dynamics of block-type foundations for machines are considered using the deterministic approach and assuming that the determined parameters are random variables. A foundation model in the form of an undeformable solid on which another undeformable solid modelling a machine is mounted via viscoelastic constraints was adopted. The dynamic load was defined by a harmonically varying signal and by a series of short duration signals. The vibration of the system was investigated for the case when stratified ground (groundwater occurred within the side backfill was present. Calculation results illustrating the theoretical analyses are presented.

  17. Preparation and quality control of materials used in the reference buffer material

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, D.A.; Hnatiw, D.S.J.; Kohle, C.L.

    1992-09-15

    This document summarizes the methodologies developed for preparing the reference buffer material (RBM) for use in laboratory-scale and field-scale experiments. Two commercially available concrete mixers have been successfully used to repeatedly produce homogeneous bulk buffer and backfill materials. The components, blending procedures, quality control sampling requirements, and mixing checklists used in the production of the reference buffer material are presented. Use of these directions will ensure that consistent batching of sealing materials is achieved and operator-induced variability is minimized.

  18. High level nuclear waste repository in salt: Sealing systems status and planning report: Draft report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1985-09-01

    This report documents the initial conceptual design studies for a repository sealing system for a high-level nuclear waste repository in salt. The first step in the initial design studies was to review the current design level, termed schematic designs. This review identified practicality of construction and development of a design methodology as two key issues for the conceptual design. These two issues were then investigated during the initial design studies for seal system materials, seal placement, backfill emplacement, and a testing and monitoring plan. The results of these studies have been used to develop a program plan for completion of the sealing system conceptual design. 60 refs., 26 figs., 18 tabs.

  19. Realization of a new plant by the COMUF in Gabon

    International Nuclear Information System (INIS)

    The techno-economics of uranium beneficiation in Gabon are examined with costs associated with the renewal and enlargement of an existing processing plant. Items of particular interest include the cost of providing facilities for the storage of over 5000m3 of pregnant liquor between the leach and solvent extraction units, the cost of obtaining 600m3 per hour of water from a source 6.5km from the plant and the use of cyclones to split the tailings into a coarse fraction for backfill with the fine fraction being deposited in a tailings dam

  20. The TSS project: Thermal simulation of drift emplacement. Final report. Phase 2. 1993-1995

    International Nuclear Information System (INIS)

    The reference concept for spent fuel management of nuclear power plants in the Federal Republic of Germany comprises both the reprocessing of spent fuel assemblies by recycling the uranium and plutonium and disposing the waste in boreholes in a salt dome and the direct disposal of the spent fuel elements. The direct disposal provides the packaging of the fuel rods in self shielding Pollux casks and their emplacement in the drifts of a repository mine in rock salt. The remaining volume of the drifts is backfilled with crushed salt immediately after the emplacement of the casks. (orig./GL)

  1. Latex-modified grouts for in-situ stabilization of buried transuranic/mixed waste

    Energy Technology Data Exchange (ETDEWEB)

    Allan, M.L.

    1996-06-01

    The Department of Applied Science at Brookhaven national Laboratory was requested to investigate latex-modified grouts for in-situ stabilization of buried TRU/mixed waste for INEL. The waste exists in shallow trenches that were backfilled with soil. The objective was to formulate latex-modified grouts for use with the jet grouting technique to enable in-situ stabilization of buried waste. The stabilized waste was either to be left in place or retrieved for further processing. Grouting prior to retrieval reduces the potential release of contaminants. Rheological properties of latex-modified grouts were investigated and compared with those of conventional neat cement grouts used for jet grouting.

  2. Radionuclide getters in the near-field chemistry of repositories. Annual report - February 1989

    International Nuclear Information System (INIS)

    A programme of work has commenced to assess the radionuclide sorption efficiency of selected inorganic 'getters' incorporated into sulphate resisting Portland cement; as a means of enhancing the retention of radioactive species by the proposed repository backfill. For this initial study, a limited number of radioisotopes have been selected, with particular reference to those likely to be mobile in an alkaline environment, ie. Ra-266, Cs-134 and I-125. The getters chosen for this stage of the programme were Clinoptilolite, Molecular Sieve 5a, Tobermorite and Ferric Floc. (author)

  3. Retrievability of spent nuclear fuel canisters; Kaeytetyn ydinpolttoaineen loppusijoituskapseleiden palautettavuus

    Energy Technology Data Exchange (ETDEWEB)

    Saanio, T. [Saanio and Riekkola Oy, Helsinki (Finland); Raiko, H. [VTT Energy, Espoo (Finland)

    1999-03-01

    As a part of the designing process of the Finnish spent nuclear fuel repository, a preliminary study has been carried out to investigate how the canisters could technically be retrieved to the ground surface. Possibility of retrieving a canister has been investigated in different phases of the disposal project. Retrievability has not been a design goal for the spent fuel repository. However, design of the repository includes some features that may ease the retrieval of canisters in the future. Spent fuel elements are packaged in massive copper-iron canisters, which are mechanically strong and long-lived. The repository consists of excavated tunnels in hard rock which are supposed to be very long-lived making the removal of the tunnel backfilling technically possible also in the future. As long as the bentonite buffer has not been installed the canister can be returned to the ground surface using the same equipment as was used when the canister was brought down to the repository and lowered into the hole. In the encapsulation station the spent fuel elements can be packaged in the other canister or in the transport cask. After a deposition tunnel has been backfilled and closed, the retrieval consists of tearing down the concrete structure at the entry of the deposition tunnel, removal of the tunnel backfilling, removal of the bentonite from the disposal hole and lifting up of the canister. Various methods, e.g., flushing the bentonite with saline solutions, can be used to detach the canister from a hole with fully saturated bentonite. Recovery will be technically possible also after closing of the disposal facility. Backfilling of the shafts and tunnels will be removed and additional new structures and systems will have to be built in the repository. After that canisters can be transported to the ground surface as described above. In addition, handling of the canisters at the ground surface will require additional facilities. Canisters can be packaged in the

  4. Modelling gas migration from a low/intermediate level nuclear waste repository

    International Nuclear Information System (INIS)

    A numerical study of gas release and migration from a hypothetical nuclear waste repository is presented. The influence of gas transport on the buildup of excess pressures within the repository and on the outflow of water into the host rock is examined. Parametric analyses indicate that hydraulic properties of the backfill material strongly affect the degree and duration of repository pressurization. However, only extreme scenarios appear to result in pressure gradients significant enough to potentially jeopardize the structural integrity of the repository. 8 refs., 4 figs

  5. Physical and chemical environment and radionuclide migration in a low level radioactive waste repository

    International Nuclear Information System (INIS)

    The expected physical and chemical environment within the low-level radioactive waste repository to be sited at Chalk River is being studied to establish the rate of radionuclide migration. Chemical conditions in the repository are being assessed for their effect on buffer performance and the degradation of the concrete structure. Experimental programs include the effect of changes in solution chemistry on radionuclide distribution between buffer/backfill materials and the aqueous phase; the chemical stability of the buffer materials and the determination of the controlling mechanism for radionuclide transport during infiltration

  6. Interactions between cement grouts and sulphate bearing ground water

    International Nuclear Information System (INIS)

    The physical, chemical and mineralogical properties of mixtures of Ordinary Portland cement and blastfurnace slag or pulverized fuel ash, exposed to a sulphate-bearing ground water at different temperatures and pressures, were investigated in order to assess the long term durability of cements for encapsulating radioactive waste and backfilling a repository. The effect of the ground water on the chemical and mineralogical characteristics of the cements is minimal. Calcite and C-S-H are present in all the samples and are durable throughout the test. Dimensional changes in the cements during setting and curing may cause weaknesses in the materials which may increase the effects of a percolating ground water. (author)

  7. Remote monitoring within the framework of rock burst prevention. Fernueberwachung in der Gebirgsschlagverhuetung

    Energy Technology Data Exchange (ETDEWEB)

    Hahnekamp, H.G.; Koenig, W.; Kuzia, M.

    1991-12-12

    The DMT Institute for Rock Control and Backfilling of Cavities has developed a technically simple remote monitoring system for use within the framwork of rock burst prevention. With this system coal faces can be continuously monitored even under difficult underground conditions without serious operating problems. For the monitoring the variables measured underground, viz. rock pressure, rock movement and deformation of test boreholes, are transmitted via the telecommunication network of the colliery to a computer on the surface, where they are evaluated online with regard to recognition of a rock burst hazard. Display of the actual monitoring situation on the computer screen permits immediate initiation of safety measures in the event of danger. (orig.).

  8. Streamlined Approach for Environmental Restoration Work Plan for Corrective Action Unit 461: Joint Test Assembly Sites and Corrective Action Unit 495: Unconfirmed Joint Test Assembly Sites Tonopah Test Range, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Jeff Smith

    1998-08-01

    This Streamlined Approach for Environmental Restoration plan addresses the action necessary for the clean closure of Corrective Action Unit 461 (Test Area Joint Test Assembly Sites) and Corrective Action Unit 495 (Unconfirmed Joint Test Assembly Sites). The Corrective Action Units are located at the Tonopah Test Range in south central Nevada. Closure for these sites will be completed by excavating and evaluating the condition of each artillery round (if found); detonating the rounds (if necessary); excavating the impacted soil and debris; collecting verification samples; backfilling the excavations; disposing of the impacted soil and debris at an approved low-level waste repository at the Nevada Test Site

  9. Effect of electrochemical etching current on prepared perforated silicon structures for neutron detectors

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qiang FAN; Yong JIANG; Chang-Yong ZHAN; Yu ZOU; Jian-Chun WU; Ning-Kang HUANG

    2013-01-01

    Neutron detector based on perforated silicon structures backfilled with neutron converting materials could be operated at a low voltage and improves the detection efficiency of thermal neutron. It is found that the intrinsic detection efficiency of thermal neutron is affected by a lot of factors such as the geometry, size, and depth of the perforation and so on. In this study, the perforated silicon was prepared by electrochemical etching. Effect of etching current on geometry, size, and depth of the perforated silicon structures for neutron detectors was also reported.

  10. Numerical Modelling of Overburden Deformations

    Directory of Open Access Journals (Sweden)

    J. Barták

    2002-01-01

    Full Text Available This paper focuses on the application and verification of mathematical models of the effect of supporting measures on the reduction of overburden deformations. The study of the behaviour of the models is divided into three parts: reduction of the tunnelling effects on the Minorit monastery by means of a jet-grouting curtain; the behaviour of the Hvížďalka backfilled tunnel and a numerical analysis of the supporting measures affecting the tunnel deformations of the Mrázovka tunnel in Prague.

  11. In-situ grouting of shallow landfill radioactive waste trenches

    International Nuclear Information System (INIS)

    This paper discusses how a backfilled trench containing low-level radioactive waste was grouted with a particulate grout. The accessible void volume of the waste zone was estimated to be 20% or 28 m3, but 30.6 m3 of grout was infected into the trench. Part of the grout forced a path outside the trench. The water permeation into the trench from monitoring wells was reduced by two orders of magnitude. The grout costs only $0.055/L; but most of the cost was in manpower, 1220 man-hours for this demonstration

  12. Design and proof of function of a closure system for an HLW-repository in rock salt. Results of the preliminary safety analysis for the Gorleben site (VSG)

    Energy Technology Data Exchange (ETDEWEB)

    Mueller-Hoeppe, Nina; Breustedt, Michael; Engelhardt, Hans-Joachim; Wolf, Johanna [DBE Technology GmbH, Peine (Germany); Buhmann, Dieter; Czaikowski, Oliver; Herbert, Horst-Juergen; Wieczorek, Klaus; Xie, Mingliang [Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH, Braunschweig (Germany)

    2015-07-01

    Within the preliminary safety analysis for the Gorleben site (VSG), a closure system was designed in order to complement the containment providing rock zone (CRZ) by sealing and backfilling measures. The design procedure as well as the technical proof of function was mainly performed according to standard procedures in civil engineering. In the context of VSG, rough individual technical proofs of several measures were carried out. Meanwhile, this gap has been closed by subsequent investigations. Altogether the results of all the individual technical proofs of function indicate that safe containment of radioactive waste is a realistic possibility at the Gorleben site.

  13. STUDY OF CARRYING CAPACITY OF A CORRUGATED METAL CONSTRUCTION BY CRITERION OF YIELD HINGE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Y. Y. Luchko

    2015-10-01

    Full Text Available Purpose. This research is aimed to: 1 calculation of equivalent forces caused by rolling stock in winter and summer seasons at different parameters of the irregularities of railway track; 2 research of bearing capacity of corrugated metal constructions (CMC in terms of development of plastic hinge in the top of the metal pipe due to irreversible residual deformation of the vertical and horizontal diameters of the pipe. Methodology. The calculation of equivalent forces is carried out according to the method of calculating the railway track on strength and stability. Further a mathematical algorithm was developed in the software environment of Mathcad 14, with which the calculations were made about the formation of a plastic hinge at the top of the pipe for different values of the irregularities of the railway track and the degree of compaction of soil backfill. In these studies, the calculations were carried out at the design value of the compaction degree of soil backfill and magnitude of dynamic loading on railway rolling stock. Findings. Analysis of multivariate calculations of testing the condition of occurrence of plastic hinge at the top of the pipe arch has revealed that the first plastic hinge, which occurs in the set of CMC is revealed only when there is a simultaneous unfavorable influence of two factors (causes. These are the factors: the assumption of the development of the track irregularities out of the allowable values without the implementation of measures to eliminate or limit the speed of trains (the first cause; reduction of compaction of soil backfill below the 90 % (the second cause. In case of absence of one of the causes the origin of the plastic hinge will not happen. Originality. It was the first time, when the bearing capacity of corrugated metal construction with large diameter (more than 6 m with account of factors complex: the degree of compaction of soil backfill, the magnitude of the dynamic loads from rolling stock

  14. Deep Energy Foundations : Geotechnical Challenges and Design Considerations

    OpenAIRE

    Abdelaziz, Sherif Lotfy Abdel Motaleb

    2013-01-01

    Traditionally, geothermal boreholes have utilized the ground energy for space heating and cooling. In this system, a circulation loop is placed in a small-diameter borehole typically extending to a depth of 200-300 ft. The hole is then backfilled with a mixture of sand, bentonite and/or cement. The loop is connected to a geothermal heat pump and the fluid inside the loop is circulated. The heat energy is fed into the ground for cooling in the summer and withdrawn from the ground for heating i...

  15. Engineered Materials Characterization Report for the Yucca Mountain Site Characterization Project, Volume 3, Revision 1, Corrosion Data and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    McCright, R D

    1998-04-01

    The Engineered Materials Characterization Report (EMCR) serves as a source of information on the properties of materials proposed as elements in the engineered barrier system (EBS) for the Yucca Mountain nuclear waste repository. Volume 3 covered the corrosion data and modeling efforts. The present report is a revision to Volume 3 and updates information on the corrosion (and other degradation modes) behavior of candidate materials for the various components of the EBS. It also includes work on the performance modeling of these materials. Work is reported on metallic barriers, basket materials, packing/backfill/invert materials, and non-metallic materials.

  16. Mechanics of non-saturated soils

    International Nuclear Information System (INIS)

    This book presents the different ways to approach the mechanics of non saturated soils, from the physico-chemical aspect to the mechanical aspect, from the experiment to the theoretical modeling, from the laboratory to the workmanship, and from the microscopic scale to the macroscopic one. Content: water and its representation; experimental bases of the behaviour of non-saturated soils; transfer laws in non-saturated environment; energy approach of the behaviour of non-saturated soils; homogenization for the non-saturated soils; plasticity and hysteresis; dams and backfilling; elaborated barriers. (J.S.)

  17. The spatial information system EramSIS in the service of geotechnical monitoring

    International Nuclear Information System (INIS)

    Backfilling activities in the Morsleben radioactive waste repository (ERAM) began in 2003. They are necessary to stabilize the intensely mined central part of the repository. Thanks to geotechnical monitoring it is possible to ensure the local structural stability and the mandatory operational safety. The use of the integrated spatial information system EramSIS right from an early stage makes it possible to locate the great number of continuously acquired measurement results in a three-dimensional model on the computer screen. The interactive visualization proved to greatly facilitate the interpretation of the various types of information. (authors)

  18. Sorption of plutonium on geological materials associated with a Chinese radioactive waste repository. Influence of pH

    International Nuclear Information System (INIS)

    The aim of this study is to characterize plutonium sorption particularly 239Pu distribution coefficients and the influence of pH on sorption processes in saturated geological materials used as a radioactive waste repository in China. The examined geological media is from a southwestern Chinese repository and consists of soil and slates. The backfill material consists of Na-bentonite from Inner Mongolia Gaomiaozi, and will be used at the Beishan high-level waste (HLW) repository, Gansu Province. The results show that the sorption capacity of Pu by geological medium in an acidic environment is low, but significantly increases with increasing pH. (author)

  19. Foreign materials in the repository - update of estimated quantities

    International Nuclear Information System (INIS)

    In a repository for spent nuclear fuel, a variety of materials are used during the construction process and during the operation of the repository. In addition to materials necessary for the construction and operation, some materials may be transported into the repository through the ventilation air, as emissions from vehicles, as waste produced by the staff etc. Both of these two types of materials are considered here and their quantities - both the introduced quantities and the quantities that remain after closure - in the repository constructed at Olkiluoto in Eurajoki, Finland are estimated here based on new information. This work is intended to update the estimations that have been made previously, and it takes advantage of the experience collected during the construction of the underground rock characterisation facility ONKALO at Olkiluoto. During this construction process, the quantities of the different construction materials introduced into the underground openings have been monitored and they form a basis for estimating the quantities to be used in the future. The estimations made in this report are specific to a KBS-3V type repository and to the Olkiluoto site, although in some cases more generic information has been used, particularly when the relevant quantities have not been monitored in the ONKALO. The estimations are based on the new repository layout produced in 2006 and consider the latest plans for grouting and rock support. As these plans are generally not final yet, several different alternative plans are assumed when necessary. Also two different strategies for the backfilling of the tunnels are considered. The most significant differences with respect to the results of an earlier estimation are related to the materials used in grouting, shotcreting and in support bolts. In the cases where a mixture of bentonite and crushed rock is the used backfill alternative, gypsum and cement are the materials with the largest quantities remaining in the

  20. Optimization of ground source heat pumps related to soil and groundwater conditions as well as grouting material; Optimierung von Waermepumpen in Bezug auf Boden- und Grundwasserverhaeltnisse sowie Verpressmaterial

    Energy Technology Data Exchange (ETDEWEB)

    Katzenbach, R.; Clauss, F.; Waberseck, T. [Technische Univ. Darmstadt (Germany). Inst. und Versuchsanstalt fuer Geotechnik; Sass, J. [Technische Univ. Darmstadt (Germany). Inst. fuer Angewandte Geowissenschaften, Fachgebiet Ingenieurgeologie

    2006-07-01

    The capacity and the performance of ground source heat pumps and seasonal thermal storage systems with borehole heat exchangers depend on the conditions of the encountered subsoil and the groundwater and furthermore on the thermal properties of the grouting material used for conclusive backfilling of the annular space after installing the heat exchanger pipes in the borehole. Intensive investigations are carried out at the Technische Universitaet Darmstadt with the aim of an economical optimisation of the dimensioning of ground source heat pumps and seasonal thermal storage systems. (orig.)

  1. Long term investigation of thermal behaviour of 110 kV underground transmission lines in the Belgrade area

    Energy Technology Data Exchange (ETDEWEB)

    Sredojevic, M.R.; Naumov, R.M.; Popovic, D.P. [Nikola Tesla Electrical Engineering Inst., Belgrade (Yugoslavia); Simic, M.D. [Electrical Utility Co., Belgrade (Yugoslavia)

    1997-12-31

    The paper describes the procedure for applying a special cable backfill material, developed and manufactured at the Institute ``Nikola Tesla`` for the thermal stabilisation and reduction of hot spot cable operating temperature, on specific hot spots of 110 kV underground transmission lines in the Belgrade area. The results presented in this paper are an important contribution to the proof of the justification and necessity of defining and introducing in practice new procedures for the thermal stabilisation and reduction of operating temperature of existing, as well as of new, underground transmission cable lines to be built. (author)

  2. The spatial information system EramSIS in the service of geotechnical monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Heller, M.; Skrzyppek, J.; Croise, J. [Colenco Power Engineering Ltd, Baden (Switzerland); Mauke, R. [Bundesamt Fur Strahlenschutz (BfS), Salzgitter (Germany); Mohlfeld, M. [Zerna, Kopper Und Partner (ZKP), Bochum (Germany)

    2005-07-01

    Backfilling activities in the Morsleben radioactive waste repository (ERAM) began in 2003. They are necessary to stabilize the intensely mined central part of the repository. Thanks to geotechnical monitoring it is possible to ensure the local structural stability and the mandatory operational safety. The use of the integrated spatial information system EramSIS right from an early stage makes it possible to locate the great number of continuously acquired measurement results in a three-dimensional model on the computer screen. The interactive visualization proved to greatly facilitate the interpretation of the various types of information. (authors)

  3. Influence of salt solutions on the swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite

    OpenAIRE

    ZHU, Chunming; Ye, Wei-Min; Chen, Yong-Gui; Chen, Bao; Cui, Yu Jun

    2013-01-01

    During the long-term operation of a deep geological repository, infiltration of groundwater with different chemical compositions can affect the buffer/backfill properties of compacted bentonite. Using a newly developed apparatus, swelling pressure and permeability tests were carried out on densely compacted GMZ01 bentonite samples, which has an initial dry density of 1.70 Mg/m3, with de-ionized water as well as NaCl and CaCl2 solutions at different concentrations. Salinity effects of infiltra...

  4. Problems of the protection of bioresources development ofthe Bovanenkovo gas condensate field

    Directory of Open Access Journals (Sweden)

    Vladimir Dmitrievich Bogdanov

    2012-12-01

    Full Text Available The data on the fish fauna and fish food resources in the Bovanenkovo gas field are presented. The estimation of fishery and fishery potential of water bodies, hydrobiological characteristics of water bodies in the studied area are given. It is shown that the arrangement of the gas field leads to overfishing BGKM fish and change the state of aquatic ecosystems associated with the violation of runoff, backfilling flood waters, crossing streams communications, water diversion, pollution, sand mining. Thehydrobionts reaction to anthropogenic influence in the area of the gas field developmentis identified and recommendations to reduce the impact on aquatic ecosystems in the period of construction are given

  5. Research on swelling clays and bitumen as sealing materials for radioactive waste repositories

    International Nuclear Information System (INIS)

    This report describes a programme of research to investigate the performance of composite seals comprising juxtaposed blocks of highly compacted bentonite clay and bitumen. It is shown that interaction of the materials can promote a self-sealing mechanism which prevents weather penetration, even when defects are present in the bitumen layer. Factors affecting seal performance are examined by means of laboratory experiments, and implications for the design of repository backfilling and sealing systems are discussed. It is concluded that design principles and material specifications should be further developed on the basis of large scale experiments. (author)

  6. Direct methods of soil-structure interaction analysis for earthquake loadings (IV)

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J. B.; Kim, D. S.; Choi, J. S.; Kwon, K. C.; Kim, Y. J.; Lee, H. J.; Kim, S. B.; Kim, D. K. [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1996-07-15

    Methodologies of SSI analysis for earthquake loadings have been reviewed. Based on the finite element method incorporating infinite element technique for the unbounded exterior region, a computer program for the nonlinear seismic analysis named as 'KIESSI-QK' has been developed. The computer program has been verified using a free-field site-response problem. The Hualien FVT stochastic finite element analysis after backfill and the blind prediction of earthquake responses have been carried out utilizing the developed computer program. The earthquake response analysis for the LSST structure has also been performed and compared with the measured data.

  7. Metal concentration

    Energy Technology Data Exchange (ETDEWEB)

    Woof, M.

    2002-03-01

    Four hydraulic excavators are in use at GM Mining's Drumshangie surface coal mining operations near Glasgow in Scotland. They load a fleet of 91 tonne capacity rigid trucks manufactured by Terex, to carry overburden to the other side of the operation for use as backfill. Site rehabilitation is also under way. Around 13-18 million tons of water per day is pumped from the mine, using former underground mine workings to carry water from one side of the pit to the other. The mine produces some 400,000 tonnes of coal/year for Scottish Power. 3 photos.

  8. Application of rock mechanics to cut-and-fill mining. Volume 3

    Energy Technology Data Exchange (ETDEWEB)

    1980-05-15

    The conference on application of rock mechanics to cut-and-fill mining was held June 1-3, 1980, at the University of Luleaa, Luleaa, Sweden. Basic rock mechanics investigations of interest involving improving the support characteristics of backfilling by adding cement, compacting, and water removal have been entered individually into EDB. The papers also cover measurements of the support capability of such fills and the application of deformation measurements and calculations using finite element computer codes to the mining of particular ore bodies, including changes in the calculations as the mining progressed. (LTN)

  9. Design and proof of function of a closure system for an HLW-repository in rock salt. Results of the preliminary safety analysis for the Gorleben site (VSG)

    International Nuclear Information System (INIS)

    Within the preliminary safety analysis for the Gorleben site (VSG), a closure system was designed in order to complement the containment providing rock zone (CRZ) by sealing and backfilling measures. The design procedure as well as the technical proof of function was mainly performed according to standard procedures in civil engineering. In the context of VSG, rough individual technical proofs of several measures were carried out. Meanwhile, this gap has been closed by subsequent investigations. Altogether the results of all the individual technical proofs of function indicate that safe containment of radioactive waste is a realistic possibility at the Gorleben site.

  10. Experimental study on the scour around a monopile in breaking waves

    DEFF Research Database (Denmark)

    Nielsen, Anders Wedel; Sumer, B. Mutlu; Ebbe, Sebastian Schjelde;

    2012-01-01

    The scour process around monopiles caused by breaking waves is studied experimentally using regular waves. The use of regular waves is conservative, which made it possible to avoid scour phenomena caused by nonbreaking waves such as scour generation and backfilling. The waves were breaking on a...... maximum scour depth found was approximately 0:60D. This was smaller than the scour observed around piles exposed to current; however, in some cases it was an order of magnitude larger than the scour caused by nonbreaking waves. This is apparently especially true for larger piles....

  11. Use of CREAMS model in experimental designs for shallow land burial of low level wastes

    International Nuclear Information System (INIS)

    A state-of-the art model developed by the US Department of Agriculture called CREAMS (A Field Scale Model for Chemicals, Runoff, and Erosion from Agricultural Management Systems) is used to simulate the hydrologic processes in soil and rock covers at shallow land waste disposal sites. Application of the CREAMS model in management of soil moisture and percolation at waste disposal sites is discussed for diverse topsoil-backfill-cobble-gravel trench cap designs tested at different field scales. 8 references, 7 figures, 3 tables

  12. STM in poslovne baze podatkov v Slovenij

    Directory of Open Access Journals (Sweden)

    Sam Brooks

    2003-01-01

    Full Text Available Through a detailed view of STM and business journals available in Slovenia, this article depicts the value of particular databases and the impact of a tremendous influx of information into the country in recent years. The two most comprehensive databases that are available from EBSCO, the world’s largest intermediary between publishers and libraries, are explored. EBSCO’s company strategies with regard to its academic databases are described. The article examines which databases are strongest in each discipline,and covers issues such as the availability of journals most-cited, full text formats,peer-review status, embargo periods, backfiles, and other important facets.

  13. Friction stir welding tool and process for welding dissimilar materials

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri; Grant, Glenn J; Jana, Saumyadeep; Mattlin, Karl F

    2013-05-07

    A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

  14. Sediment Transport

    DEFF Research Database (Denmark)

    Liu, Zhou

    Flow and sediment transport are important in relation to several engineering topics, e.g. erosion around structures, backfilling of dredged channels and nearshore morphological change. The purpose of the present book is to describe both the basic hydrodynamics and the basic sediment transport...... mechanics. Chapter 1 deals with fundamentals in fluid mechanics with emphasis on bed shear stress by currents, while chapter 3 discusses wave boundary layer theory. They are both written with a view to sediment transport. Sediment transport in rivers, cross-shore and longshore are dealt with in chapters 2...

  15. Recommended values for the distribution coefficient (Kd) to be used in dose assessments for decommissioning the Zion Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan T.

    2014-06-09

    ZionSolutions is in the process of decommissioning the Zion Nuclear Power Plant. The site contains two reactor Containment Buildings, a Fuel Building, an Auxiliary Building, and a Turbine Building that may be contaminated. The current decommissioning plan involves removing all above grade structures to a depth of 3 feet below grade. The remaining underground structures will be backfilled. The remaining underground structures will contain low amounts of residual licensed radioactive material. An important component of the decommissioning process is the demonstration that any remaining activity will not cause a hypothetical individual to receive a dose in excess of 25 mrem/y as specified in 10CFR20 SubpartE.

  16. Recommended values for the distribution coefficient (Kd) to be used in dose assessments for decommissioning the Zion Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, T. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-09-24

    ZionSolutions is in the process of decommissioning the Zion Nuclear Power Plant. The site contains two reactor Containment Buildings, a Fuel Building, an Auxiliary Building, and a Turbine Building that may be contaminated. The current decommissioning plan involves removing all above grade structures to a depth of 3 feet below grade. The remaining underground structures will be backfilled. The remaining underground structures will contain low amounts of residual licensed radioactive material. An important component of the decommissioning process is the demonstration that any remaining activity will not cause a hypothetical individual to receive a dose in excess of 25 mrem/y as specified in 10CFR20 SubpartE.

  17. Stability analysis of large-scale stope using stage subsequent filling mining method in Sijiaying iron mine

    Directory of Open Access Journals (Sweden)

    Zhiqiang Yang

    2015-02-01

    Full Text Available To improve mining production capacity, a stage subsequent filling mining (SSFM method is employed for Sijiaying iron mine. The height of the stage stope is approximately 100 m. As there are farmlands and villages on the surface of the mine, the surface deformation should be controlled when the ore is mined out for the purpose of stope stability and minimizing surface subsidence. In this paper, according to the site-specific geological conditions, the self-stability of the stage-filling body was analyzed, and the failure mechanism of backfilling body was defined. Thus the relationship between the exposed height of filling body and the required strength was obtained. Next, the stability of backfilling body and the characteristics of surface subsidence due to mining of −450 m level were analyzed using physical modeling. Finally, a three-dimensional numerical model was established using FLAC3D, with which the surface subsidence and the stability of stope were achieved. The results show that the stope basically remains stable during the two-step recovery process. The maximum magnitude of the incline is 10.99 mm/m, a little larger than the permissible value of 10 mm/m, and the horizontal deformation is 5.9 mm/m, approaching the critical value of 6.0 mm/m, suggesting that the mine design is feasible for safety mining.

  18. Orientating analyses related to the experiment 'Thermal simulation of gallery emplacement' by means of the ADINA program system

    International Nuclear Information System (INIS)

    The licencing of the reference concept of direct ultimate disposal of spent fuel elements requires the proof of safe handling, transport and storage of self-shielding containers in the repository. To be able to prove that, the demonstration test ''Thermal Simulation of Gallery Emplacement (TSS)'' is carried out in the Asse salt mine at a depth of 800 m to study the thermomechanical behaviour of the backfilling material, salt grit, and of the rock surrounding the containers. In addition, and accompanying the experiment, thermomechanical computer models are to be verified or validated on the basis of the measuring results. Orientating analyses are performed by means of the finite-element program system ADINA, using materials models available in ADINA. Because of the considerable insecurity as regards the determination of primary stresses and rock pressure, and the formulation of the materials laws in particular for the salt grit backfilling material, an attempt is made, by means of appropriate set-ups, to delimit, in terms of engineering, the thermomechanical behaviour of salt grit for a heated and unheated gallery. (orig./HP)

  19. Final design and performance of in situ testing in Grimsel

    International Nuclear Information System (INIS)

    This report is focused on the design, engineering, and construction aspects of the in situ test carried out at the Grimsel underground laboratory in Switzerland. This reproduces the AGP-granite concept of ENRESA for HLW repositories in crystalline rock. Two heaters, similar in dimensions and weight to the canisters in the reference concept, have been placed in a horizontal drift with a 2.28-m diameter, a total test length of 17.4 m, and backfilled with a total of 115.7 † of highly-compacted bentonite blocks. The backfilled area has been closed with a concrete plug which is 2.7 m thick. More than 600 sensors have been installed in the test to monitor different parameters such as temperature, pressures, humidity, etc., within both the buffer material and the host rock. The installation was completed and commissioned in February 1997, and then the heating phase, which will last for at least 3 years, was started. During this period, the test will basically be operated in an automatic mode, controlled and monitored from Spain via modem. The report is the Final Report from AITEMIN for Phase 4 of the project and includes a description of the test configuration and layout; the design, engineering, and manufacturing aspects of the different test components and equipment; the emplacement operation; and the as built information regarding the final position of the main components and the sensors. (Author)

  20. Interaction analysis of back-to-back mechanically stabilized earth walls

    Directory of Open Access Journals (Sweden)

    Sadok Benmebarek

    2016-10-01

    Full Text Available Back-to-back mechanically stabilized earth walls (BBMSEWs are encountered in bridge approaches, ramp ways, rockfall protection systems, earth dams, levees and noise barriers. However, available design guidelines for BBMSEWs are limited and not applicable to numerical modeling when back-to-back walls interact with each other. The objective of this paper is to investigate, using PLAXIS code, the effects of the reduction in the distance between BBMSEW, the reinforcement length, the quality of backfill material and the connection of reinforcements in the middle, when the back-to-back walls are close. The results indicate that each of the BBMSEWs behaves independently if the width of the embankment between mechanically stabilized earth walls is greater than that of the active zone. This is in good agreement with the result of FHWA design guideline. However, the results show that the FHWA design guideline underestimates the lateral earth pressure when back-to-back walls interact with each other. Moreover, for closer BBMSEWs, FHWA design guideline strongly overestimates the maximum tensile force in the reinforcement. The investigation of the quality of backfill material shows that the minor increase in embankment cohesion can lead to significant reductions in both the lateral earth pressure and the maximum tensile force in geosynthetic. When the distance between the two earth walls is close to zero, the connection of reinforcement between back-to-back walls significantly improves the factor of safety.

  1. The Hualien large-scale seismic test for soil-structure interaction research. Response analysis of embedded structure during forced vibration tests and during earthquakes

    International Nuclear Information System (INIS)

    Predictive and correlative analyses of the forced vibration tests of the large-scale model structure embedded in the gravelly layer before and after backfill were performed. Also similar analyses of the same structure subjected to earthquakes were performed. As the result, the following was clarified; (1) Predicted fundamental system frequency of the forced vibration test before backfill by means of three-dimensional FEM complex dynamic response analysis code (named 'TB3D') was 9% higher than the test result. The predictive analysis also showed the applicability of 'TB3D', getting well predicted result of the basic characteristics of the response difference appearing in the tests due to the excitation position difference in the horizontal excitation cases, getting well simulated result of the test where phase lag frequency response curve is a convex function downward, and so on. The analysis with the ground model incorporating the Vs change following the construction stage progress brought good fundamental system frequency agreement with the test, indicating the importance of the appropriate incorporation of such Vs change into the ground model. (author)

  2. The Hualien large-scale seismic test for soil-structure interaction research. Response analysis of embedded structure during forced vibration tests and during earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Ueshima, Teruyuki; Tanaka, Yukihisa; Okamoto, Toshiro; Tohma, Junichi; Kokusho, Takeharu [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Abiko Research Lab.

    1997-08-01

    Predictive and correlative analyses of the forced vibration tests of the large-scale model structure embedded in the gravelly layer before and after backfill were performed. Also similar analyses of the same structure subjected to earthquakes were performed. As the result, the following was clarified; (1) Predicted fundamental system frequency of the forced vibration test before backfill by means of three-dimensional FEM complex dynamic response analysis code (named `TB3D`) was 9% higher than the test result. The predictive analysis also showed the applicability of `TB3D`, getting well predicted result of the basic characteristics of the response difference appearing in the tests due to the excitation position difference in the horizontal excitation cases, getting well simulated result of the test where phase lag frequency response curve is a convex function downward, and so on. The analysis with the ground model incorporating the Vs change following the construction stage progress brought good fundamental system frequency agreement with the test, indicating the importance of the appropriate incorporation of such Vs change into the ground model. (author)

  3. Ternary DNA chip based on a novel thymine spacer group chemistry.

    Science.gov (United States)

    Yang, Yanli; Yildiz, Umit Hakan; Peh, Jaime; Liedberg, Bo

    2015-01-01

    A novel thymine-based surface chemistry suitable for label-free electrochemical DNA detection is described. It involves a simple two-step sequential process: immobilization of 9-mer thymine-terminated probe DNAs followed by backfilling with 9-mer thymine-based spacers (T9). As compared to commonly used organic spacer groups like 2-mercaptoethanol, 3-mercapto-1-propanol and 6-mercapto-1-hexanol, the 9-mer thymine-based spacers offer a 10-fold improvement in discriminating between complementary and non-complementary target hybridization, which is due mainly to facilitated transport of the redox probes through the probe-DNA/T9 layers. Electrochemical measurements, complemented with Surface Plasmon Resonance (SPR) and Quartz Crystal Microbalance (QCM-D) binding analyses, reveal that optimum selectivity between complementary and non-complementary hybridization is obtained for a sensing surface prepared using probe-DNA and backfiller T9 at equimolar concentration (1:1). At this particular ratio, the probe-DNAs are preferentially oriented and easily accessible to yield a sensing surface with favorable hybridization and electron transfer characteristics. Our findings suggest that oligonucleotide-based spacer groups offer an attractive alternative to short organic thiol spacers in the design of future DNA biochips. PMID:25465760

  4. The geomicrobiology of calcium montmorillonite (Fuller's Earth)

    International Nuclear Information System (INIS)

    Oxfordshire Fuller's Earth contains high populations of aerobic heterotrophic microorganisms and smaller populations of anaerobic heterotrophs. These groups seem to be generally unaffected by depth. The aerobic heterotroph activity in Fuller's Earth extract is continuous indicating that the necessary organic carbon is available. Chemical analysis has shown that all other necessary nutrients are present in the waters sampled. Activity can also be stimulated by the addition of TCA cycle intermediates. It is likely that the carbon dioxide produced by the aerobic heterotrophs could be utilised by autotrophic populations. Similarly, bicarbonate rich groundwaters could also supply inorganic carbon for them. These populations already exist at low levels and include corrosion important microorganisms. The organic carbon thus produced by the autotrophs could be used as a source for further heterotrophic activity. These findings indicate that microbial inhibition would only occur if the availability of organic carbon was controlled. The use of Fuller's Earth as a backfill material in other groundwater environments, especially those rich in bicarbonate, may stimulate various microbial groups and lead to interactions affecting waste isolation. It would thus be prudent to reduce or eliminate the organic carbon content in Fuller's Earth should it be used as a backfill material. (author)

  5. Evaluation of Interface Shear Strength Properties of Geogrid Reinforced Foamed Recycled Glass Using a Large-Scale Direct Shear Testing Apparatus

    Directory of Open Access Journals (Sweden)

    Arul Arulrajah

    2015-01-01

    Full Text Available The interface shear strength properties of geogrid reinforced recycled foamed glass (FG were determined using a large-scale direct shear test (DST apparatus. Triaxial geogrid was used as a geogrid reinforcement. The geogrid increases the confinement of FG particles during shear; consequently the geogrid reinforced FG exhibits smaller vertical displacement and dilatancy ratio than FG at the same normal stress. The failure envelope of geogrid reinforced FG, at peak and critical states, coincides and yields a unique linear line possibly attributed to the crushing of FG particles and the rearrangement of crushed FG after peak shear state. The interface shear strength coefficient α is approximately constant at 0.9. This value can be used as the interface parameter for designing a reinforced embankment and mechanically stabilized earth (MSE wall when FG is used as a lightweight backfill and triaxial geogrid is used as an extensible earth reinforcement. This research will enable FG, recently assessed as suitable for lightweight backfills, to be used together with geogrids in a sustainable manner as a lightweight MSE wall. The geogrid carries tensile forces, while FG reduces bearing stresses imposed on the in situ soil. The use of geogrid reinforced FG is thus significant from engineering, economical, and environmental perspectives.

  6. Development of drive in soil improvement machine (Galapagos/Ritela BZ 40); Jisoshiki doshitsu kairyoki (Garapagosu/Ritera, BZ 40) no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Komoriya, Y. [Komatsu Ltd., Tokyo (Japan)

    1997-01-25

    The soil produced during various types of pipe construction was used in reality for reclamation or treated in the soil improvement plant, however, there is problem of high disposal cost and transportation cost due to the lack of place for disposal and far distance. Further, high cost due to lack of pit sand collecting place for backfilling, and further, nature destruction due to collect pit sand and so forth are the problems. As for the field treatment system using developed drive in soil improvement machine, BZ 40, the soil excavated by oil pressure shovel is loaded as it is in BZ 40, solidifying agent is added, mixed, crushed and stability treatment is carried out. The improved soil particle size is adjusted by vibrating screaming machine connected to vehicle body and is loaded in the dump car for temporary storage and is reused as backfilling after the setting of the pipe. Residual soil disposal cost, transportation cost and cost for buying pit sand was reduced widely by the construction method using this machine, and further, improvement of natural environment was possible by reducing the use of pit sand. 4 refs., 1 tab.

  7. The potential for microbial life in a Canadian high-level nuclear fuel waste disposal vault

    International Nuclear Information System (INIS)

    Recent studies have concluded that microbial contamination of a nuclear fuel waste disposal vault is inevitable. Factors that will affect the development of substantial population of micro-organisms include: physiological tolerance of microbes; fluid movement in a vault; availability of nutrients; and availability of energy sources. It is difficult to resolve whether microbial growth will either positively or negatively affect the performance of a vault. One of the necessary steps towards ultimately answering this question is to assess the potential for microbial growth in a disposal vault, based on a nutrient and energy budget. This report gives a quantitative (but conservative) inventory of nutrients and potential energy sources present in a Canadian nuclear fuel waste vault, which hypothetically could support the growth of micro-organisms. Maximum population densities are calculated based on these inventories and assuming that all conditions for microbial growth are optimal, although this will certainly not be the case. Laboratory studies under the vault-relevant conditions are being performed to put realistic boundaries on the calculated numbers. Initial results from these studies, combined with data from a natural analogue site indicate that the calculated population densities could be overestimated by four to five orders of magnitude. Limited data show no effect of the presence of microbes on the transport of Tc, I, and Sr in backfill sand columns. Additional work is needed to address transport effects on buffer and backfill clay columns

  8. Stability analysis of large-scale stope using stage subsequent filling mining method in Sijiaying iron mine

    Institute of Scientific and Technical Information of China (English)

    Zhiqiang Yang; Shuhua Zhai; Qian Gao; Maohui Li

    2015-01-01

    To improve mining production capacity, a stage subsequent filling mining (SSFM) method is employed for Sijiaying iron mine. The height of the stage stope is approximately 100 m. As there are farmlands and villages on the surface of the mine, the surface deformation should be controlled when the ore is mined out for the purpose of stope stability and minimizing surface subsidence. In this paper, according to the site-specific geological conditions, the self-stability of the stage-filling body was analyzed, and the failure mechanism of backfilling body was defined. Thus the relationship between the exposed height of filling body and the required strength was obtained. Next, the stability of backfilling body and the character-istics of surface subsidence due to mining of ?450 m level were analyzed using physical modeling. Finally, a three-dimensional numerical model was established using FLAC3D, with which the surface subsidence and the stability of stope were achieved. The results show that the stope basically remains stable during the two-step recovery process. The maximum magnitude of the incline is 10.99 mm/m, a little larger than the permissible value of 10 mm/m, and the horizontal deformation is 5.9 mm/m, approaching the critical value of 6.0 mm/m, suggesting that the mine design is feasible for safety mining. ? 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by

  9. The techniques of reclaiming subsidence areas by use of a hydraulic dredge pump in Chinese coal mines

    International Nuclear Information System (INIS)

    The technique of reclaiming disturbed lands by use of a hydraulic dredge pump (HDP) has been used in the reclamation of subsidence areas in Chinese coal mines. This paper discusses the operation principle of the technique and its available conditions and summarizes its reclamation procedures, which are being used in current reclamation practice. The characteristics of the soil reclaimed by HDP were studied. The results showed that the reclaimed soil by use of HDP resulted in a massive structure soil, which was the mixture of original topsoil and subsoil, and had high clay content and no district horizontal layers. The moisture characteristics of the reclaimed soil was the most severe influence factor to plant growth because of the high moisture content and slow infiltration. The soil fertility assessments indicated that the reclaimed soil was very poor. Therefore, the improvements of the reclaimed soils and the HDP technique are needed. Based on the analysis of the previous technical processes, a new technical process for the HDP reclamation method was presented in this paper. The author thought that the two processes such as excavation of soil and backfill and sedimentation needed to be improved, and the other important processes such as removal and backfill of topsoil, establishment of drainage system, etc., should be added

  10. Influence of EPS Geofoam Buffers on the Static Behavior of Cantilever Earth-Retaining Walls

    Directory of Open Access Journals (Sweden)

    Özgür L. Ertuğrul

    2012-03-01

    Full Text Available In this study, the effect of expanded polystyrene (EPS buffers on lateral stresses and deflections of model retaining walls with various flexibility values were investigated. For this purpose, 0.7 m high model walls were instrumented and 1-g model tests were performed in laboratory environment. In the first group of tests, the wall models retain only granular cohesionless backfill whereas in the second and third group of tests, EPS deformable buffers of two different thicknesses were installed between the wall and granular backfill. Tests were repeated for four different wall thicknesses and results were discussed comparatively. As wall flexibility increases, there is a decrease in the load reduction pattern of the buffer. On the other hand, utilization of geofoam buffers with flexible cantilever walls still provides substantial decrease in wall thrust and deflections thus leading to more economical retaining structure design. The lateral earth pressure coefficients determined through model tests were compared to those calculated from Coulomb's theory for active lateral earth stresses. A graph is provided for the estimation of lateral earth pressure coefficients for various combinations of wall flexibilities and buffer characteristics.

  11. Containment of uranium in the proposed Egyptian geologic repository for radioactive waste using hydroxyapatite.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert Charles; Hasan, Ahmed Ali Mohamed; Headley, Thomas Jeffrey; Sanchez, Charles Anthony (University of Arizona, Yuma, AZ); Zhao, Hongting; Salas, Fred Manuel; Hasan, Mahmoud A. (Egyptian Atomic Energy Authority, Cairo, Egypt); Holt, Kathleen Caroline

    2004-04-01

    Currently, the Egyptian Atomic Energy Authority is designing a shallow-land disposal facility for low-level radioactive waste. To insure containment and prevent migration of radionuclides from the site, the use of a reactive backfill material is being considered. One material under consideration is hydroxyapatite, Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, which has a high affinity for the sorption of many radionuclides. Hydroxyapatite has many properties that make it an ideal material for use as a backfill including low water solubility (K{sub sp}>10{sup -40}), high stability under reducing and oxidizing conditions over a wide temperature range, availability, and low cost. However, there is often considerable variation in the properties of apatites depending on source and method of preparation. In this work, we characterized and compared a synthetic hydroxyapatite with hydroxyapatites prepared from cattle bone calcined at 500 C, 700 C, 900 C and 1100 C. The analysis indicated the synthetic hydroxyapatite was similar in morphology to 500 C prepared cattle hydroxyapatite. With increasing calcination temperature the crystallinity and crystal size of the hydroxyapatites increased and the BET surface area and carbonate concentration decreased. Batch sorption experiments were performed to determine the effectiveness of each material to sorb uranium. Sorption of U was strong regardless of apatite type indicating all apatite materials evaluated. Sixty day desorption experiments indicated desorption of uranium for each hydroxyapatite was negligible.

  12. Retrieval options study

    International Nuclear Information System (INIS)

    This Retrieval Options Study is part of the systems analysis activities of the Office of Nuclear Waste Isolation to develop the scientific and technological bases for radioactive waste repositories in various geologic media. The study considers two waste forms, high level waste and spent fuel, and defines various classes of waste retrieval and recovery. A methodology and data base are developed which allow the relative evaluation of retrieval and recovery costs and the following technical criteria: safety; technical feasibility; ease of retrieval; probable intact retrieval time; safeguards; monitoring; criticality; and licensability. A total of 505 repository options are defined and the cost and technical criteria evaluated utilizing a combination of facts and engineering judgments. The repositories evaluated are selected combinations of the following parameters: Geologic Media (salt, granite, basalt, shale); Retrieval Time after Emplacement (5 and 25 years); Emplacement Design (nominal hole, large hole, carbon steel canister, corrosion resistant canister, backfill in hole, nominal sleeves, thick wall sleeves); Emplacement Configuration (single vertical, multiple vertical, single horizontal, multiple horizontal, vaults; Thermal Considerations; (normal design, reduced density, once-through ventilation, recirculated ventilation); Room Backfill; (none, run-of-mine, early, 5 year delay, 25 year delay, decommissioned); and Rate of Retrieval;

  13. Design and construction of a seepage cut off wall using the slurry trench technique in cold temperatures at the Horizon Dam project

    Energy Technology Data Exchange (ETDEWEB)

    Barr, L.A.; Sobkowicz, J.C. [Thurber Engineering Ltd., Calgary, AB (Canada)

    2010-07-01

    This paper described the design and construction of a soil-cement-bentonite seepage cut off water that was constructed in 2007 as part of the Horizon Dam project at Canadian Natural Resources Ltd. Horizon oil sands site. The Horizon Dam is an earth retention structure which diverts the Tar River around the mine and plant site, and creates a man-made lake providing replacement fish habitat. It was necessary to build the cut off wall to control seepage through the native coarse grained alluvial deposits encountered under the dam and to minimize the risk of piping due to large hydraulic gradients created by the lake. This paper discussed the design of the dam and the field investigation using different geotechnical drilling methods, geophysics and in-situ testing to support design of the cut off wall. Specifically, the paper discussed a literature review and laboratory testing program that were carried out to assess the appropriate backfill mix to be used. The construction of the cut off wall took place at the end of winter using the slurry trench technique. As such, some unique constructability issues were encountered because of cold weather, the use of cement in the backfill, and the native soil conditions. It was concluded that although strict quality control/assurance measures were implemented, one defect in the cut off wall occurred, which required mitigation to provide a product that met the design intentions. 5 refs., 1 tab., 15 figs.

  14. Evolution in performance assessment modeling as a result of regulatory review

    Energy Technology Data Exchange (ETDEWEB)

    Rowat, J.H.; Dolinar, G.M.; Stephens, M.E. [AECL Chalk River Labs., Ontario (Canada)] [and others

    1995-12-31

    AECL is planning to build the IRUS (Intrusion Resistant Underground Structure) facility for near-surface disposal of LLRW. The PSAR (preliminary safety assessment report) was subject to an initial regulatory review during mid-1992. The regulatory authority provided comments on many aspects of the safety assessment documentation including a number of questions on specific PA (Performance Assessment) modelling assumptions. As a result of these comments as well as a separate detailed review of the IRUS disposal concept, changes were made to the conceptual and mathematical models. The original disposal concept included a non-sorbing vault backfill, with a strong reliance on the wasteform as a barrier. This concept was altered to decrease reliance on the wasteform by replacing the original backfill with a sand/clinoptilolite mix, which is a better sorber of metal cations. This change lead to changes in the PA models which in turn altered the safety case for the facility. This, and other changes that impacted performance assessment modelling are the subject of this paper.

  15. EEC Round Robin test on the repository system simulation - clay option. Final report EEC research contract No. Fl 1W-0116-l

    Energy Technology Data Exchange (ETDEWEB)

    Cantale, C.; Castelli, S.; Donato, A.; Traverso, D.M.

    1989-06-01

    The objective of the 'Reporting System Simulation Test (RSST) was to define a test method for the evaluation of waste performances in various geological disposal scenarios, with the possibility to simulate various additional materials, like canister, backfilling, overpack and host rock. The test procedure for the clay-option needed to be developed, especially with reference to the solution preparation and Eh (redox potential) measurements. The necessity to work in an argon atmosphere glove box brings in some operational complications, mainly in the case of the Eh measurement, filtering and final volume determination. The reproducibility of the experimental data does not seem to be particularly good, probably due to the difficulties in standardizing the experimental procedure. An effort should be done to improve these aspects. The tightness of the container and the physical stability of the rock/backfill/grill with pins/synthetic interstitial claywater system are excellent. The leaching data reveal that the clay contribution to the final ionic concentration of the solution is not negligible and should be better evaluated. The overall data-set shows that the glass leach rate, as expressed by Boron mass loss, decreases with time.

  16. Centrifuge modelling of the pushover failure of an electricity transmission tower

    Energy Technology Data Exchange (ETDEWEB)

    Richards, D.J. [Southampton Univ. (United Kingdom). School of Civil Engineering and the Environment; White, D.J. [Western Australia Univ., Crawley, WA (Australia). Centre for Offshore Foundation Systems, Faculty of Engineering, Computing and Mathematics

    2010-04-15

    The foundation systems of broad-based lattice power transmission towers must be designed to resist uplift, lateral and downward forces arising from the tower's weight, and tension within the conductor wires and wind loadings. This study investigated foundation failure mechanisms during the rapid horizontal pushover of a power transmission tower. The centrifuge model tests were designed to simulate a wind gust loading or broken transmission line response. The tower was supported on 4 pad foundations set in clay and backfilled with sand. The loads at each foundation were measured during fast and flow pushover. The influence of tensile resistance mobilized at the underside of the footings was investigated. The measured performance of the tower footings showed good agreement with results obtained from a series of tests conducted to measure a single footing subjected to vertical loading. Tower response was back-analyzed as a simple push-pull model. The calculated uplift capacity of the footing backfill showed good agreement with the observed response of tower footings subjected to slow pushover. The additional capacity mobilized during fast pushover was caused by tensile resistance created by the reverse bearing capacity beneath the base of the footings. 30 refs., 3 tabs., 11 figs.

  17. Geochemical constraints on the microbial contamination of a hypothetical UK deep geological repository

    International Nuclear Information System (INIS)

    In this report some simple calculations are carried out to examine the constraints on the maximum effect of microbial contamination of a high level waste repository. The approach used is conservative as total inventories of carbon and other nutrients are calculated without regard to the inaccessibility to organisms and kinetic constraints on the concentration of diffuse sources on to organisms. From these calculations it appears that the main limiting factor would be 'available' carbon and, as long as carbonates within the bentonite backfill cannot be used, this should limit maximum dry biomass to 3 x 103g within a 3.3 m3 backfill region. Although the total potential free energy available from canister corrosion is large, the rate of utilisation of such energy will be subject to, as yet, poorly defined kinetic constraints. An important finding is that if oxic corrosion is the only source of energy for microbes then canister corrosion by this method would be negligible. It is concluded that the possibility of significant microbial contamination cannot be excluded. Potentially important consequences would include radionuclide transport on mobile organisms, particularly of poorly retarded species such as Tc and Np, and enhanced solubility of particular nuclides when complexed with microbial organic by-products. The subject is discussed further. (author)

  18. Experimental study on Chamoise tunnel argilites after excavation

    International Nuclear Information System (INIS)

    The argilites that are currently excavated from the Bure site at 500 m deep will stay for decades in surface deposit. They will be exposed to rain, evaporation and frost. After this long period of time, the argilites could be used to backfill the galleries. In this perspective, the mechanical parameters that can be obtained when using these argilites as a gallery backfill material are of prime importance. Previous studies showed that a Young modulus of 20 MPa is a minimum value required to avoid the extension of EDZ (Excavation Damage Zone) at long-term. To investigate this issue, an experimental program on the Chamoise tunnel Effingen marls deposit has been carried out. It happens that the Chamoise tunnel marls correspond to the same geological layer than the Bure argilite. Moreover, the deposit is about 20 years old, so the Chamoise marls are considered as an analogue of the argilites after surface deposit. This allows to obtain some data about the effects of alteration processes due to rain, evaporation and frost on the geotechnical properties of the material. (authors)

  19. Effects of gaseous radioactive nuclides on the design and operation of repositories for spent LWR fuel in rock salt

    International Nuclear Information System (INIS)

    Information relating to the identities and amounts of gaseous radionuclides present in spent LWR fuel and to their release from canistered spent fuel under plausible storage and disposal conditions was assembled, reviewed, and analyzed. Information was also reviewed and analyzed on several other subjects that relate to the integrity of the carbon steel canister in which the spent fuel is to be encapsulated and to the expected rates of transfer of gaseous radionuclides through crushed salt backfill within a disposal room in a reference repository in rock salt. The advantages and disadvantages were considered for several different canister-backfill materials, and recommendations were made regarding preferred materials. Other recommendations relate to encapsulation procedures and specifications and to needs for additional experimental studies. The objective of this work was to provide reference information, conclusions, and recommendations that could be used to establish design and operating conditions and procedures for a bedded salt repository for spent LWR fuel and that could also be used to help evaluate the safety of the repository. The results of this work will also generally apply to spent fuel repositories in domal salt. However, because the domal salt may have little or no brine inclusions within it, there may be little or no possibility that brine will migrate into open spaces around an emplaced canister. Addordingly, some of the concerns that result from the possible occurrence of brine migration in bedded salt may be of no importance in domal salt

  20. Move mountains... but don`t harm the newts!

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Since the fine for killing a great crested newt is 5000 pounds, Wardell Armstrong took special precautions when working to remediate a derelict and contaminated site at Hednesford Brickworks, near Cannock in Staffordshire, UK. The 32 ha site involved a former brickworks, collieries, two spoil heaps, a large infilled clay pit and 12 abandoned mineshafts. Backfilling by the National Coal Board had created a blackened landscape without vegetation known as `The Moon`. However, two settlement lagoons had become an important breeding area for great crested newts. The clean-up operation involved shifting 720,000 m{sup 3} of muck. Shallow miner workings were treated with drilling and grouting, mine shafts capped with reinforced concrete, and material moved and compacted down to depths of 3 m. A gas venting scheme was installed to contain landfill gas from the backfilled clay pit. The newts were held in a safe area while engineering works rumbled along around them. Safe `runs` and channels were built for newts to cross under the roads. 4 km of surface water courses were built and 22 ha of land landscaped with plants, cycleway and paths, resulting in a regenerated site with happy newts. 1 photo.

  1. Results from simulated remote-handled transuranic waste experiments at the Waste Isolation Pilot Plant (WIPP)

    International Nuclear Information System (INIS)

    Multi-year, simulated remote-handled transuranic waste (RH TRU, nonradioactive) experiments are being conducted underground in the Waste Isolation Pilot-Plant (WIPP) facility. These experiments involve the near-reference (thermal and geometrical) testing of eight full size RH TRU test containers emplaced into horizontal, unlined rock salt boreholes. Half of the test emplacements are partially filled with bentonite/silica-sand backfill material. All test containers were electrically heated at about 115 W/each for three years, then raised to about 300 W/each for the remaining time. Each test borehole was instrumented with a selection of remote-reading thermocouples, pressure gages, borehole vertical-closure gages, and vertical and horizontal borehole-diameter closure gages. Each test emplacements was also periodically opened for visual inspections of brine intrusions and any interactions with waste package materials, materials sampling, manual closure measurements, and observations of borehole changes. Effects of heat on borehole closure rates and near-field materials (metals, backfill, rock salt, and intruding brine) interactions were closely monitored as a function of time. This paper summarizes results for the first five years of in situ test operation with supporting instrumentation and laboratory data and interpretations. Some details of RH TRU waste package materials, designs, and assorted underground test observations are also discussed. Based on the results, the tested RH TRU waste packages, materials, and emplacement geometry in unlined salt boreholes appear to be quite adequate for initial WIPP repository-phase operations

  2. Conceptual design of shaft seals for a nuclear waste disposal vault

    International Nuclear Information System (INIS)

    The concept of a disposal vault in the Canadian Shield for the effective isolation of nuclear fuel wastes is being assessed as part of the Canadian Nuclear Fuel Waste Management Program. The vault would be accessed from the surface by a number of shafts, which would likely penetrate the vault environment and intersect significant rock fractures and thereby form preferential pathways for the migration of radionuclides from the disposal area to the biosphere. Golder Associates were retained to conduct a conceptual design study of sealing and backfilling the shafts. The first volume of this report reviews current shaft sinking and lining technologies, and recommends the preferred construction methods for the shafts. Factors that could affect the design of a shaft seal system are reviewed, and a conceptual shaft seal is proposed. The second volume addresses the performance assessment of a shaft seal system. While there are no specific performance criteria against which to compare the anticipated containment characteristics of the shaft seal system proposed, the methodology developed for the performance assessment of the reference design should enable the design to be modified to meet performance criteria as they are developed. The report estimates that it will cost $133.7 million in 1986 Canadian dollars to seal three reference shafts, including $18 million for labour and equipment, $103.4 million for backfill and sealing materials, $9.5 million for project indirect costs, and $2.8 million project management. (author). 53 refs., 36 tabs., 43 figs

  3. Three-dimensional helical computed tomographic evaluation of three obturation techniques: In vitro study

    Directory of Open Access Journals (Sweden)

    M Chokkalingam

    2011-01-01

    Full Text Available Aim: The purpose of this study was to evaluate the adequacy of three obturation techniques namely lateral condensation, EQ Fil (backfill obturation and thermafil (core carrier obturation techniques using three-dimensional (3D helical computed tomography (CT by volume rendering method. Materials and Methods: Thirty freshly extracted teeth were randomly divided into three groups of 10 teeth each. Biomechanical preparation was done in all the teeth using rotary instruments. All three sets of teeth were placed in helical CT slice scanner and were imaged before obturation. The three sets were then obturated by following methods: Group I: lateral condensation, Group II: EQ Fil (backfill and Group III: thermafil (core carrier obturation.Volume of the pulp chamber and gutta-percha after obturation were calculated using volume rendering technique and adequacy of the obturation techniques were calculated. Statistical Analysis Used: One-way ANOVA and Multiple-Range Tukey Test by Tukey-HSD procedure Results: Mean change in lateral condensation (0.005±0.002 was significantly higher than that of thermafil obturation (0.002±0.001 [P<0.05]. Conclusions: Conventional lateral condensation technique showed maximal inadequacy of obturation and thermafil obturation technique showed the least inadequacy of obturation when the volume of the specimens were calculated and reconstructed

  4. Visible calculation of mining index based on stope 3D surveying and block modeling

    Institute of Scientific and Technical Information of China (English)

    Liu Xiaoming; Luo Zhouquan; Yang Biao; Lu Guang; Cao Shengxiang; Jiang Xinjian

    2012-01-01

    Aimed at the CMS laser scanning theory and characteristic,a combined actual situation of stope N4-5 of Fankou Lead-Zinc Mine and complementary monitoring of the stope were carried out by carefully choosing two measuring points.The cavity 3D visible model was created by large-scale mining industry software Surpac after changing the measured data.The stope mine design model,bottom structural model and backfill model of the south and north sides of the stope N4-5 were established according to the stope design data.On this basis,the stope block model was established,and then block attribute was estimated.The amount the ore remains,mullock,backfill and total mined ore were calculated through the solid model restrains.Finally,the stope mining dilution rate and loss rate reached 8.2%and 1.47%,respectively.The practice indicates that the mining index visible calculation method based on cavity 3D monitoring and stope block modeling can make up the deficiency of adopting the solid model to directly carry out the Boolean operation.The stope mining indexes obtained by this method are accurate and reliable,and can be used to guide the actual production management and estimate the mining quality.

  5. Maxey Flats in situ waste grouting demonstration

    International Nuclear Information System (INIS)

    The Maxey Flats Disposal Site located in Fleming County, Kentucky was added to the US EPA National Priority List in 1986 and is currently being evaluated for remediation and closure under the CERCLA/Superfund program. The Commonwealth of Kentucky has cosponsored a program with the US DOE Low Level Waste Management Program to demonstrate various remedial technologies which may be applied to source containment at the Maxey Flats site. This paper describes the field demonstration of in-situ waste grouting using a particulate (cement) grout. This demonstration is a follow-on to a similar demonstration using a solution grout. Both programs were designed to develop injection techniques, to assess the ability of the grout to fill the accessible voids within the waste/backfill matrix, to measure the reduction in the hydraulic conductivity of the waste/backfill matrix, and to determine the operational difficulties in implementing a site-wide grouting program. The paper concludes with lessons-learned during the project and estimated costs for full scale implementation

  6. Reuse of waste cutting sand at Lawrence Livermore National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Mathews, S., LLNL

    1998-02-25

    Lawrence Livermore National Laboratory (LLNL) examined the waste stream from a water jet cutting operation, to evaluate the possible reuse of waste garnet sand. The sand is a cutting agent used to shape a variety of materials, including metals. Nearly 70,000 pounds of waste sand is generated annually by the cutting operation. The Environmental Protection Department evaluated two potential reuses for the spent garnet sand: backfill in utility trenches; and as a concrete constituent. In both applications, garnet waste would replace the sand formerly purchases by LLNL for these purposes. Findings supported the reuse of waste garnet sand in concrete, but disqualified its proposed application as trench backfill. Waste sand stabilized in ac concrete matrix appeared to present no metals-leaching hazard; however, unconsolidated sand in trenches could potentially leach metals in concentrations high enough to threaten ground water quality. A technical report submitted to the San Francisco Bay Regional Water Quality Control Board was reviewed and accepted by that body. Reuse of waste garnet cutting sand as a constituent in concrete poured to form walkways and patios at LLNL was approved.

  7. Sponge-Templated Macroporous Graphene Network for Piezoelectric ZnO Nanogenerator.

    Science.gov (United States)

    Li, Xinda; Chen, Yi; Kumar, Amit; Mahmoud, Ahmed; Nychka, John A; Chung, Hyun-Joong

    2015-09-23

    We report a simple approach to fabricate zinc oxide (ZnO) nanowire based electricity generators on three-dimensional (3D) graphene networks by utilizing a commercial polyurethane (PU) sponge as a structural template. Here, a 3D network of graphene oxide is deposited from solution on the template and then is chemically reduced. Following steps of ZnO nanowire growth, polydimethylsiloxane (PDMS) backfilling and electrode lamination completes the fabrication processes. When compared to conventional generators with 2D planar geometry, the sponge template provides a 3D structure that has a potential to increase power density per unit area. The modified one-pot ZnO synthesis method allows the whole process to be inexpensive and environmentally benign. The nanogenerator yields an open circuit voltage of ∼0.5 V and short circuit current density of ∼2 μA/cm(2), while the output was found to be consistent after ∼3000 cycles. Finite element analysis of stress distribution showed that external stress is concentrated to deform ZnO nanowires by orders of magnitude compared to surrounding PU and PDMS, in agreement with our experiment. It is shown that the backfilled PDMS plays a crucial role for the stress concentration, which leads to an efficient electricity generation.

  8. Verification of substitution of bentonites by montmorillonitic clays summary report on Czech montmorillonitic clays

    International Nuclear Information System (INIS)

    Czech bentonites and smectite-rich clays were characterised in order to study if they could be used as buffer and backfill materials instead of non-Czech commercial bentonites. The characterisation work was orgnized by RAWRA (the Czech Radioactive Waste Repository Authority) and the main part of the work was performed in the Czech Republic at Charles University and at Czech Technical University. Parallel and complementary characterisation was conducted in Finland in Sweden. This report was compiled with the aim to summarise the results, and to compare the methods and results gained in different testing laboratories. The characterisation included mineralogical, chemical and geotechnical investigations and experiments on thermal stability and sorption. There were some variations between the results gained in different laboratories. This was mainly due to differences between the testing methods used but also due to heterogeneity of the samples. The Czech bentonite-clays from Rokle and Strance clay deposits contained relatively high amount of swelling minerals and thus can be considered as potential buffer and backfill materials. (orig.)

  9. The geomicrobiology of European mines relevant to radioactive waste disposal

    International Nuclear Information System (INIS)

    Samples for microbiological analysis were taken from experimental mines, which are being used to investigate the technology for radioactive waste disposal, in Belgium, Federal Republic of Germany and Sweden. In total four mines were examined from the three countries. Generally, the number and types of microorganisms increased as the salinity of the water samples decreased. Higher populations were present in the least saline waters of Stripa (Sweden). Here exposed gallery stream-water contained aerobic and anaerobic bacteria as well as autotrophic and heterotrophic types. Water from a deep borehole, drilled into the Stripa granite from within the 360 m level gallery, contained a predominance of anaerobic heterotrophic bacteria. Activity monitored by gas chromatographic techniques showed that this population was organic carbon limited. A shallow borehole sample contained mainly aerobic heterotrophic bacteria which were also carbon limited. Samples from the mines in the FRG and Belgium contained small or no populations of bacteria determined by cultural techniques. Mol (Belgium) Boom clay, a potential backfill material, contained no determinable microbial content, and nutrients extracted from it were unable to support environmental isolates. For this reason it is considered a superior backfill material to Fuller's Earth (calcium montmorillonite). (author)

  10. Three dimensional model evaluation of physical alterations of the Caloosahatchee River and Estuary: Impact on salt transport

    Science.gov (United States)

    Sun, Detong; Wan, Yongshan; Qiu, Chelsea

    2016-05-01

    Numerical hydrodynamic modeling provides quantitative understanding of how physical alterations of an estuary may alter the waterbody hydrodynamics and the rate of mixing with the ocean. In this study, a three dimensional hydrodynamic model (CH3D) was used to compare simulated salinities between the existing condition and five historical cases representing varying physical alterations of the Caloosahatchee Estuary involving (1) removal of the headwater structure (S-79); (2) removal of the downstream causeway to Sanibel Island; (3) backfilling an oyster bar near the estuary month; (4) refilling the navigation channel; and (5) the pre-development bathymetric condition. The results suggested that some alterations including the Sanibel Causeway, backfilling the oyster bar and the S-79 structure may have some local effects but did not change estuarine salinity structure significantly. Refilling the navigation channel had a more profound effect, resulting in a dry season salinity reduction of about 5 when compared with the existing condition. The reduced salt transport was more pronounced with the pre-development bathymetry because the estuary as a whole was much shallower than today. The significant system-wide increase in salt transport caused by the historic dredging of the navigation channel in the Caloosahatchee Estuary has significant implications in the development of attainable environmental flow targets for protecting the estuarine ecosystem.

  11. Numerical Simulation of Hysteretic Live Load Effect in a Soil-Steel Bridge

    Directory of Open Access Journals (Sweden)

    Sobótka Maciej

    2014-03-01

    Full Text Available The paper presents numerical simulation of hysteretic live load effect in a soil-steel bridge. The effect was originally identified experimentally by Machelski [1], [2]. The truck was crossing the bridge one way and the other in the full-scale test performed. At the same time, displacements and stress in the shell were measured. The major conclusion from the research was that the measured quantities formed hysteretic loops. A numerical simulation of that effect is addressed in the present work. The analysis was performed using Flac finite difference code. The methodology of solving the mechanical problems implemented in Flac enables us to solve the problem concerning a sequence of load and non-linear mechanical behaviour of the structure. The numerical model incorporates linear elastic constitutive relations for the soil backfill, for the steel shell and the sheet piles, being a flexible substructure for the shell. Contact zone between the shell and the soil backfill is assumed to reflect elastic-plastic constitutive model. Maximum shear stress in contact zone is limited by the Coulomb condition. The plastic flow rule is described by dilation angle ψ = 0. The obtained results of numerical analysis are in fair agreement with the experimental evidence. The primary finding from the performed simulation is that the slip in the interface can be considered an explanation of the hysteresis occurrence in the charts of displacement and stress in the shell.

  12. Construction Technology of 19 m High Terrace Concrete Foundation in Shanghai Shimao Chasm Hotel%上海世茂深坑酒店19m高梯田式混凝土基础施工技术

    Institute of Scientific and Technical Information of China (English)

    危鼎; 钱海波; 谢高华; 王勃龙; 杨媛鹏

    2015-01-01

    上海世茂深坑酒店19m高梯田式回填混凝土基础,具有浇筑地形复杂、厚度大、多标高、截面不规则等特点,故钢筋加工安装、模板支设、混凝土浇筑工艺复杂,难度很大。使用BIM技术确定合理分层、分块浇筑顺序,并应用MIDAS对混凝土温度分布进行分析,为实际养护提供了参考。另外,通过电子测温仪进行测温,实时跟踪,保证了回填混凝土基础的质量。%19 meters high terrace foundation with backfill concrete foundation of Shanghai Shimao Chasm Hotel has the characteristics of complex terrain, large thickness, multi elevation, irregular section, etc. Therefore, reinforcement processing and installation, template support and concrete pouring process are complex and difficult. BIM technique is used to determine the reasonable stratification and the pouring sequence. The temperature distribution of concrete is analyzed by MIDAS, which provides a reference for the actual maintenance. In addition, temperature is measured by real⁃time tracking electronic thermometer to guarantee the quality of backfill concrete foundation.

  13. Effect of transport-pathway simplifications on projected releases of radionuclides from a nuclear waste repository (Sweden)

    Science.gov (United States)

    Selroos, Jan-Olof; Painter, Scott L.

    2012-12-01

    The Swedish Nuclear Fuel and Waste Management Company has recently submitted an application for a license to construct a final repository for spent nuclear fuel, at approximately 500 m depth in crystalline bedrock. Migration pathways through the geosphere barrier are geometrically complex, with segments in fractured rock, deformation zones, backfilled tunnels, and near-surface soils. Several simplifications of these complex migration pathways were used in the assessments of repository performance that supported the license application. Specifically, in the geosphere transport calculations, radionuclide transport in soils and tunnels was neglected, and deformation zones were assumed to have transport characteristics of fractured rock. The effects of these simplifications on the projected performance of the geosphere barrier system are addressed. Geosphere performance is shown to be sensitive to how transport characteristics of deformation zones are conceptualized and incorporated into the model. Incorporation of advective groundwater travel time within backfilled tunnels reduces radiological dose from non-sorbing radionuclides such as I-129, while sorption in near-surface soils reduces radiological doses from sorbing radionuclides such as Ra-226. These results help quantify the degree to which geosphere performance was pessimistically assessed, and provide some guidance on how future studies to reduce uncertainty in geosphere performance may be focused.

  14. Reclamation of a contaminated utility corridor, Surrey, BC

    Energy Technology Data Exchange (ETDEWEB)

    Janes, M. [Horizon Engineering Ltd., North Vancouver, BC (Canada); Clarke, J. [Quantum Remediation Services Ltd., Langley, BC (Canada); Driedger, J. [Wellspring Consulting Inc., Port Moody, BC (Canada); Newton, D. [Morrow Environmental Consultants Ltd., Burnaby, BC (Canada); Warren, R. [Shell Canada Ltd., Calgary, AB (Canada)

    2001-07-01

    Remediation of a large utility corridor hosting a 100 mm diameter gas line, a 150 mm diameter water main and a 400 mm diameter sanitary sewer, by means of removal of contaminated soil and replacement with granular fills, is discussed. One of the challenges to be overcome was that remediation of the site could not extend beyond the edge of a major roadway. Also, completion of the project required placement of a barrier to prevent the contaminant from returning onto the site. The paper describes design of a shoring system to support the roadway adjacent to the property. Excavation was conducted to the full depth of the utility corridor including the utility bedding materials. A plug of engineered low permeability backfill was placed and compacted around the utilities. The design of the engineered fill met the requirements for low permeability, workable, batchable, compactable mix that could be re-excavated in the future to provide access for future utility installation should it be required. Since the utility corridor was located beneath the right-of-way, the engineered backfill had to have adequate strength to support the roadway and to prevent large and differential settlements. The design employed on the project also paid special attention to the potential for minor settlements and changes in groundwater conditions that may have led to cracking of a cementitious mixture. 2 refs., 2 tabs., 4 figs.

  15. Anticipated Degradation Modes of Metallic Engineered Barriers for High-Level Nuclear Waste Repositories

    Science.gov (United States)

    Rodríguez, Martín A.

    2014-03-01

    Metallic engineered barriers must provide a period of absolute containment to high-level radioactive waste in geological repositories. Candidate materials include copper alloys, carbon steels, stainless steels, nickel alloys, and titanium alloys. The national programs of nuclear waste management have to identify and assess the anticipated degradation modes of the selected materials in the corresponding repository environment, which evolves in time. Commonly assessed degradation modes include general corrosion, localized corrosion, stress-corrosion cracking, hydrogen-assisted cracking, and microbiologically influenced corrosion. Laboratory testing and modeling in metallurgical and environmental conditions of similar and higher aggressiveness than those expected in service conditions are used to evaluate the corrosion resistance of the materials. This review focuses on the anticipated degradation modes of the selected or reference materials as corrosion-resistant barriers in nuclear repositories. These degradation modes depend not only on the selected alloy but also on the near-field environment. The evolution of the near-field environment varies for saturated and unsaturated repositories considering backfilled and unbackfilled conditions. In saturated repositories, localized corrosion and stress-corrosion cracking may occur in the initial aerobic stage, while general corrosion and hydrogen-assisted cracking are the main degradation modes in the anaerobic stage. Unsaturated repositories would provide an oxidizing environment during the entire repository lifetime. Microbiologically influenced corrosion may be avoided or minimized by selecting an appropriate backfill material. Radiation effects are negligible provided that a thick-walled container or an inner shielding container is used.

  16. Neuronal responses to water flow in the marine slug tritonia diomedea

    Directory of Open Access Journals (Sweden)

    Jeffrey Blackwell

    2005-07-01

    Full Text Available The marine slug Tritonia diomedea must rely on its ability to touch and smell in order to navigate because it is blind. The primary factor that influences its crawling direction is the direction of water flow (caused by tides in nature. The sensory cells that detect flow and determine flow direction have not been identified. The lateral branch of Cerebral Nerve 2 (latCeN2 has been identified as the nerve that carries sensory axons to the brain from the flow receptors inthe oral tentacles. Backfilling this nerve to the brain resulted in the labeling of a number of cells located throughout the brain. Most of the labeled cells are concentrated in the cerebral ganglion where the nerve enters the brain. The medial and lateral branches of CeN2 were backfilled for comparison of the pattern of cells from each nerve. A map of the cells innervated by latCeN2 reveals the location of the stained cells. Extracellular recording from latCeN2 revealed its involvement in the detection of water flow and orientation. The nerve becomes active in response to water flow stimulation. Intracellular recordings of the electrical activity of these cells in a live animal will be the next step to determine if these cells are the flow receptors.

  17. Hydrothermal conditions and resaturation times in underground openings for a nuclear waste repository in the Umtanum flow at the Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    Numerical simulation techniques have been used to study heat flow and pore fluid migration in the near field of storage tunnels and canister storage holes in a proposed high-level nuclear waste repository in the Umtanum Basalt at the Basalt Waste Isolation Project site at Hanford, Washington. Particular emphasis was placed on evaluating boiling conditions in the host rock. Sensitivity studies were performed to determine the influence of variations in critical site-specific parameters which are not presently accurately known. The results indicate that, even when rather extreme values are assumed for key hydrothermal parameters, the volume of rock dried by boiling of pore fluids is negligible compared to the volume of excavated openings. The time required for saturation of backfilling materials is thus controlled by the volume of the mined excavations. When realistic values for the parameters of the natural and man-made systems are used resaturation is predicted to occur within less than two years after backfilling is placed. The approximations used in the analyses, and their limitations, are discussed in the body of the report. Recommendations are made for additional studies of the thermohydrological behavior of a high-level nuclear waste repository. 31 references, 76 figures, 7 tables

  18. Neuronal Responses to Water Flow in the Marine Slug Tritonia diomedea

    Directory of Open Access Journals (Sweden)

    James A. Murray

    2005-01-01

    Full Text Available The marine slug Tritonia diomedea mustrely on its ability to touch and smell in order to navigate because it is blind. The primaryfactor that influences its crawling direction is the direction of water flow (caused bytides in nature. The sensory cells that detect flow and determine flow directionhave not been identified. The lateral branch of Cerebral Nerve 2 (latCeN2 has beenidentified as the nerve that carries sensory axons to the brain from the flow receptors inthe oral tentacles. Backfilling this nerve to the brain resulted in the labeling of a numberof cells located throughout the brain. Most of the labeled cells are concentrated in the cerebral ganglion where the nerve enters thebrain. The medial and lateral branches of CeN2 were backfilled for comparison of thepattern of cells from each nerve. A map of the cells innervated by latCeN2 reveals thelocation of the stained cells. Extracellular recording from latCeN2 revealed itsinvolvement in the detection of water flow and orientation. The nerve becomes activein response to water flow stimulation. Intracellular recordings of the electricalactivity of these cells in a live animal will be the next step to determine if these cells arethe flow receptors.

  19. Monitoring technique for seepage line of tailings dam

    Institute of Scientific and Technical Information of China (English)

    李夕兵; 蒋卫东

    2003-01-01

    An automatic monitoring technique of the seepage line, including the monitoring design, the automatic monitoring system and the backfill technique of the measuring probe of pore-water pressure, was used in a tailings dam, and a shallow refractive seismic method was investigated for obtaining the seepage line of those areas outside the monitoring zone. The results show that the automatic monitoring has the error within ± 3 % relative to piezometric tube method and improves monitoring efficiency greatly, and the shallow refractive seismic method has the error within ± 10% but expands the area of monitoring. Both of them can be used for a daily measurement in monitoring the seepage line. The result of the automatic monitoring also shows that not only the design of the survey line and the backfill technique of the measuring probe of pore-water pressure are reasonable and economic but also the reliability and safety of the automatic monitoring system are better. Testing result by the shallow refractive seismic method in tailings reveals that the energy excited by hammering iron sheet-pole is strong enough and safe, and that the character of anti-jamming by the detectors with long tailcone is better.

  20. Independent Verification Review And Survey of the Argonne National Laboratory Building 301 Footprint Argonne, Illinois

    International Nuclear Information System (INIS)

    The objectives of the verification activities were to provide independent document and field data reviews in evaluating the adequacy and accuracy of the contractor's procedures and FSS results. The onsite verification survey was performed in order to generate independent radiological scan data and sample data (if necessary) for use by the DOE to verify that remedial actions were effective in reaching background levels. ORISE performed onsite verification survey activities of the Building 301 footprint area at ANL on September 14, 2009. The onsite activities included collecting independent gamma scan measurements. The survey results did not identify any locations of elevated radiation levels exceeding twice background within the footprint area. Following onsite activities, ORISE was provided a partial FSS laboratory data package to review. Upon identifying several technical issues with the analyses and reporting, ORISE was informed that those FSS samples were being re-analyzed; however, DOE approved the backfill of the area on September 16, 2009 prior to receiving the re-analyzed results. The subsequent laboratory report for the samples that were re-analyzed was provided to ORISE on November 2, 2009 and although the Building 301 footprint area was already backfilled, the review determined the analytical results were acceptable.