Soil reinforcement with geosynthetics

Directory of Open Access Journals (Sweden)

Bessaim Mohammed Mustapha

2018-01-01

Full Text Available The proportionality of existence of land with good bearing to erect any building or building is very small, to remedy this deficiency it is necessary to resort to techniques of reinforcement of the soils which can constitute a very important development. Among these methods of remediation, there is reinforcement by the geosynthetics which constitute an effective solution to these constraints. This process tends to stabilize the soil in question with increased load bearing capacity in civil engineering and geotechnical works such as embankments, slopes, embankments and hydraulic structures, with an inestimable gain in time, economy and durability while preserving the natural and environmental aspect.

Accelerated load testing of geosynthetic base reinforced pavement test sections.

Science.gov (United States)

2011-02-01

The main objective of this research is to evaluate the benefits of geosynthetic stabilization and reinforcement of subgrade/base aggregate layers in flexible pavements built on weak subgrades and the effect of pre-rut pavement sections, prior to the ...

Development of an accelerated creep testing procedure for geosynthetics : technical summary.

Science.gov (United States)

1997-09-01

Temperature-creep relationships in geosynthetics vary for each type of geogrid and depend on many factors such as polymer structure, manufacture process, degree of crystallinity, and glass-transition temperature. The extrapolation procedures to predi...

Smart timber bridge on geosynthetic reinforced soil (GRS) abutments

Science.gov (United States)

Adam Senalik; James P. Wacker; Travis K. Hosteng; John Hermanson

2017-01-01

Recently, Buchanan County, Iowa, has cooperated with the U.S. Federal Highway Administration (FHWA), USDA Forest Service, Forest Products Laboratory (FPL), and Iowa State University’s Bridge Engineering Center (ISU–BEC) to initiate a project involving the construction and monitoring of a glued-laminated (glulam) timber superstructure on geosynthetic reinforced soil (...

Seismic performance of geosynthetic-soil retaining wall structures

Science.gov (United States)

Zarnani, Saman

Vertical inclusions of expanded polystyrene (EPS) placed behind rigid retaining walls were investigated as geofoam seismic buffers to reduce earthquake-induced loads. A numerical model was developed using the program FLAC and the model validated against 1-g shaking table test results of EPS geofoam seismic buffer models. Two constitutive models for the component materials were examined: elastic-perfectly plastic with Mohr-Coulomb (M-C) failure criterion and non-linear hysteresis damping model with equivalent linear method (ELM) approach. It was judged that the M-C model was sufficiently accurate for practical purposes. The mechanical property of interest to attenuate dynamic loads using a seismic buffer was the buffer stiffness defined as K = E/t (E = buffer elastic modulus, t = buffer thickness). For the range of parameters investigated in this study, K ≤50 MN/m3 was observed to be the practical range for the optimal design of these systems. Parametric numerical analyses were performed to generate design charts that can be used for the preliminary design of these systems. A new high capacity shaking table facility was constructed at RMC that can be used to study the seismic performance of earth structures. Reduced-scale models of geosynthetic reinforced soil (GRS) walls were built on this shaking table and then subjected to simulated earthquake loading conditions. In some shaking table tests, combined use of EPS geofoam and horizontal geosynthetic reinforcement layers was investigated. Numerical models were developed using program FLAC together with ELM and M-C constitutive models. Physical and numerical results were compared against predicted values using analysis methods found in the journal literature and in current North American design guidelines. The comparison shows that current Mononobe-Okabe (M-O) based analysis methods could not consistently satisfactorily predict measured reinforcement connection load distributions at all elevations under both static

Experimental determination and evaluation of the friction behavior of geosynthetics; Experimentelle Ermittlung und Bewertung des Reibungsverhaltens von Geokunststoffen

Energy Technology Data Exchange (ETDEWEB)

Heinemann, Maik

2016-08-17

In many fields of geotechnical engineering geosynthetics have established itself as an alternative to common used earth materials. Particularly in landfill sealing systems many different types of geosynthetics are used together. In embankments geosynthetics form inclined planes. The safety against sliding must be proved for all contact surfaces. For this purpose, the knowledge of the friction behavior of the geosynthetics is required. Normally, the friction behavior is modeled analytically with the Coulomb failure criterion. The Coulomb friction parameters usually must be determined experimentally. In spite of the good state of the art and numerous studies into geosynthetics, in detail, there are still issues relating to the determination of friction behavior of geosynthetics, to the application of the Coulomb failure criterion and to the assessment of the friction parameters with a view to the time- and temperature-dependent behavior of synthetics. The main objective of this work is to contribute to a reliable determination of the friction behavior and to a correct assessment of the evaluated test results as the basis for a reliable and economical dimensioning of structures with geosynthetics. For this, the measurement technique of a standard large direct shear box was upgraded by the author, so that the effective normal stress can be measured below the test surface. Also tests with very small normal stresses can be carried out with this modification. Furthermore, a force-controlled test device was designed for studies of the influences arising from long-term combined compressive and shear loads and temperature. Based on experimental investigations inadequacies in the current experimental procedure are identified. In addition, the impact of factors are quantified, which are often ignored or considered to be marginal in practice. With further experimental investigations it is demonstrated that the linear Coulomb failure criterion is valid for limited normal stress

A comparison of analytical approaches for the assessment of seismic displacements of geosynthetically reinforced geostructures

DEFF Research Database (Denmark)

Tzavara, I.; Tsompanakis, Y.; Zania, Varvara

2012-01-01

Aim of the current study is to assess the dynamic response of reinforced soil structures and the potential of the geosynthetics to prevent the seismic induced instabilities taking advantage of their reinforcing effect. For this purpose, representative models of reinforced soil slopes are developed...

Geosynthetic clay liners - slope stability field study

International Nuclear Information System (INIS)

Carson, D.A.; Daniel, D.E.; Koerner, R.M.; Bonaparte, R.

1997-01-01

A field research project was developed to examine the internal shear performance of geosynthetic clay liners (GCLs). Several combinations of cross sections were assembled using GCL materials that were available at the time of project initiation. The cross sections utilized were intended to simulate landfill cover applications. Thirteen (13) resulting test plots were constructed on two different slope angles, and each plot is instrumented for physical displacement and soil moisture characteristics. Test plots were constructed in a manner that dictated the shear plane in the clay portion of the GCL product. The project purpose is to assess field performance and to verify design parameters associated with the application of GCLs in waste containment applications. Interim research data shows that test slopes on 2H:1V show global deformation, but little internal shear evidence, and the 3H:1V slopes show little deformation at approximately 650 days. The research is ongoing, and this paper presents the most recent information available from the project

Long-term performance of geosynthetic clay liners in cappings

International Nuclear Information System (INIS)

Maubeuge, K.P. von; Fricke, A.

1998-01-01

Geosynthetic clay liners (GCLs) are relatively thin composite materials combining bentonite clay and geosynthesis (usually geotextiles). GCLs have been employed by the waste industry for well over a decade now, and their level of usage is rapidly increasing world-wide. In landfill facilities, GCLs are generally used to replace or augment compacted clay liners. Until recently, the decision to do so has primarily been based on the availability of clay material on site (i.e., economic considerations). However, the advantages in using a GCL over other sealing elements such as compacted clay are not only economic but technically based, and the economic benefits extend beyond the construction phase, as a thin GCL can increase the revenue earning potential of a facility. This paper will highlight the shear behaviour of GCLs and demonstrate the long-term stability. (orig.)

Utilization of Waste Clay from Boron Production in Bituminous Geosynthetic Barrier (GBR-B Production as Landfill Liner

Directory of Open Access Journals (Sweden)

Müfide Banar

2016-01-01

Full Text Available Bituminous geomembranes, one type of geosynthetics, include a hot bituminous mixture with mineral filler and reinforcement. In this study, boron production waste clay (CW was used as filler to produce a geosynthetic barrier with bentonite, waste tire, and bitumen. Bentonite and waste tires were used as auxiliary fillers and bitumen as the binder. CW/bitumen, CW/bentonite/bitumen, and CW/waste tire/bitumen mixtures were prepared by using a laboratory mixer at 100°C. Hot mixtures were extruded into strips by using a lab-scale corotating twin screw extruder (L/D: 40 followed by die casting (2 mm × 100 mm. Glass fleece or nonwoven polyester was used as reinforcement material and while die casting, both sides of the reinforcement materials were covered with bituminous mixture. Thickness, mass per unit area, tensile strength, elongation at yield, and hydraulic conductivity were used to characterize the geomembranes. Among all geomembranes, nonwoven polyester covered with 30% bitumen-70% boron waste clay mixture (PK-BTM30CW70 was found to be the most promising in terms of structure and mechanical behaviour. After that, consequences of its exposure to distilled water (DW, municipal solid waste landfill leachate (L-MSW, and hazardous waste landfill leachate (L-HW were examined to use for an innovative impermeable liner on solid waste landfills.

La durabilité des géosynthétiques dans les installations de stockage de déchets : le projet Durageos DURAGEOS. Durability of geosynthetics used in landfills

Directory of Open Access Journals (Sweden)

FARCAS, Fabienne ; PONS, Carlos ; BOUCHEZ, Théodore ; MAZÉAS, Laurent ; MÉRY, Jacques ; TOUZE-FOLTZ, Nathalie ; DURRIEU, Claude ; FAYOLLE, Bruno ; RICHAUD, Emmanuel ; LANOË, Marie ; MARTINS, Jean ; PIERSON, Patrick ; SALDI, Fethi

2012-08-01

Full Text Available Les géosynthétiques sont de plus en plus utilisés pour renforcer les barrières d'étanchéité des installations de stockage des déchets non dangereux. Afin de réduire l'impact environnemental des installations, les utilisateurs de ces matériaux ont donc besoin de guides et de recommandations sur leur mise en œuvre délicate, mais également d'estimations sur leur durée de vie. Cet article nous présente les moyens mis en œuvre par le projet Durageos pour mieux connaître et prédire les processus de vieillissement des géomembranes en polyéthylène haute densité et des géosynthétiques bentonitiques.The DURAGEOS project studies geosynthetics (HDPE geomembranes and GCLs ageing mechanisms under combined action of mechanical stresses, microorganisms and/or oxygen in connection with mass transfer. Physico-chemical and mechanical features of model and commercial geosynthetics aged in laboratory allow the development of a kinetic model of prediction of the lifetime coupled to a model of mass transfer. The models will be validated by geosynthetics sampled on landfill sites. Ecotoxicological risks and environmental external costs of transfers are to be assessed.

Critical interfaces in geosynthetic multilayer liner system of a landfill

Directory of Open Access Journals (Sweden)

Qian Xuede

2008-12-01

Full Text Available This study is to identify the critical interface in a geosynthetic multilayer liner system by examining the effects of the interface shear strength of liner components, leachate level, leachate buildup cases, and peak and residual interface strengths. According to current landfill design procedures, conducting stability analysis along the same interface at both the back slope and base may result in a non-conservative result. The critical interfaces with the minimum factor of safety are generally found at different locations along the back slope and base. The critical interface for a multilayer liner system cannot simply be assumed during stability analysis. It can shift from one interface to another with changes in the leachate level and with different leachate buildup cases. The factor of safety for an interface with a high friction angle and low apparent cohesion generally drops much more quickly than it does under inverse conditions when the leachate level increases. The failure interface in a liner system under residual conditions is usually different from the failure interface under peak conditions.

Capturing strain localization behind a geosynthetic-reinforced soil wall

Science.gov (United States)

Lai, Timothy Y.; Borja, Ronaldo I.; Duvernay, Blaise G.; Meehan, Richard L.

2003-04-01

This paper presents the results of finite element (FE) analyses of shear strain localization that occurred in cohesionless soils supported by a geosynthetic-reinforced retaining wall. The innovative aspects of the analyses include capturing of the localized deformation and the accompanying collapse mechanism using a recently developed embedded strong discontinuity model. The case study analysed, reported in previous publications, consists of a 3.5-m tall, full-scale reinforced wall model deforming in plane strain and loaded by surcharge at the surface to failure. Results of the analysis suggest strain localization developing from the toe of the wall and propagating upward to the ground surface, forming a curved failure surface. This is in agreement with a well-documented failure mechanism experienced by the physical wall model showing internal failure surfaces developing behind the wall as a result of the surface loading. Important features of the analyses include mesh sensitivity studies and a comparison of the localization properties predicted by different pre-localization constitutive models, including a family of three-invariant elastoplastic constitutive models appropriate for frictional/dilatant materials. Results of the analysis demonstrate the potential of the enhanced FE method for capturing a collapse mechanism characterized by the presence of a failure, or slip, surface through earthen materials.

A geosynthetic reinforcement solution to prevent the formation of localized sinkholes

Energy Technology Data Exchange (ETDEWEB)

Villard, P.; Gourc, J. P.; Giraud, H. [Universite Joseph Fourier, LIRIGM, Grenoble (France)

2000-10-01

A research program to guard against the risk of accidents linked to the presence of small diameter cavities under both road and railway lines is described. The program involves study of the complex behaviour of the overlying fill in the event of sinkhole formation, given that the deformation of the geosynthetic membrane results from the progressive loading of the overlying soil layer and not from the collapse of the underlying soil. Full-scale tests were carried out on reinforced, instrumented road and railway structures subjected to localized collapse. Experimental work was accompanied by a numerical study of the mechanics involved in sinkhole formation. Experimental results were analyzed and compared with the results of the three-dimensional finite element modeling. Similarity of the results suggests that formation of a stable arch for two metre cavities and an unstable arch for four metre cavities, filled with 1.5 m thick fill consisting of large grain size granular material, is satisfactory for small diameter cavities at moderate depths. However, this solution is not suitable for large large diameter cavities at moderate depths. 18 refs., 22 figs.

Behavior of granular rubber waste tire reinforced soil for application in geosynthetic reinforced soil wall

Directory of Open Access Journals (Sweden)

G. G. D. RAMIREZ

Full Text Available AbstractLarge quantities of waste tires are released to the environment in an undesirable way. The potential use of this waste material in geotechnical applications can contribute to reducing the tire disposal problem and to improve strength and deformation characteristics of soils. This paper presents a laboratory study on the effect of granular rubber waste tire on the physical properties of a clayey soil. Compaction tests using standard effort and consolidated-drained triaxial tests were run on soil and mixtures. The results conveyed an improvement in the cohesion and the angle of internal friction the clayey soil-granular rubber mixture, depending on the level of confining stress. These mixtures can be used like backfill material in soil retaining walls replacing the clayey soil due to its better strength and shear behavior and low unit weight. A numerical simulation was conducted for geosynthetic reinforced soil wall using the clayey soil and mixture like backfill material to analyzing the influence in this structure.

Avaliação de recomendações normativas sobre o uso de ensaios no controle de qualidade de fabricação de geossintéticos Evaluation of standard recommendations on the use of tests for manufacturing quality control of geosynthetics

Directory of Open Access Journals (Sweden)

Carina M. L. Costa

2008-06-01

Full Text Available A utilização de materiais poliméricos designados por geossintéticos tem aumentando significativamente nos últimos anos na Engenharia Civil. Para desempenhar adequadamente a função para a qual foram projetados, os geossintéticos devem ser submetidos a um rigoroso processo de controle de qualidade durante a fabricação. Discussões sobre a freqüência e os principais tipos de ensaios de laboratório utilizados nesse processo de controle para dois tipos de geossintéticos, os geotêxteis e as geomembranas, os materiais mais utilizados da famíla dos geossintéticos, são abordados no presente trabalho. As análises efetuadas com base em normas disponíveis no Brasil, nos EUA e na Europa mostram que no cenário nacional não há recomendações normativas sobre o controle de qualidade para a maioria das aplicações de geotêxteis e geomembranas, sendo o assunto pouco discutido na literatura técnica. No cenário internacional, as normas Européias se destacam como o conjunto de práticas mais completo para ensaios de controle de qualidade de fabricação, considerando os diversos tipos de aplicação dos geossintéticos na Engenharia Civil.The use of polymeric materials known as geosynthetics in Civil Engineering applications has increased significantly in the last few years. In order to perform adequately, geosynthetics need to be manufactured according to rigorous quality control procedures. This paper addresses the frequency and the main types of laboratory tests used for quality control of geotextiles and geomembranes, which are the most largely used materials within the geosynthetic family. Analyses based on technical standards from Brazil, USA and Europe show the need of quality control recommendations for a large number of applications of geotextiles and geomembranes in Brazil. Also, very limited information on this topic is available in Brazilian literature. Conversely, European standards on the subject take into consideration a

Model tests of geosynthetic reinforced slopes in a geotechnical centrifuge

International Nuclear Information System (INIS)

Aklik, P.

2012-01-01

Geosynthetic-reinforced slopes and walls became very popular in recent years because of their financial, technical, and ecological advantages. Centrifuge modelling is a powerful tool for physical modelling of reinforced slopes and offers the advantage to observe the failure mechanisms of the slopes. In order to replicate the gravity induced stresses of a prototype structure in a geometrically 1/N reduced model, it is necessary to test the model in a gravitational field N times larger than that of the prototype structure. In this dissertation, geotextile-reinforced slope models were tested in a geotechnical centrifuge to identify the possible failure mechanisms. Slope models were tested by varying slope inclination, tensile strengths of the geotextiles, and overlapping lengths. Photographs of the geotextile reinforced slope models in flight were taken with a digital camera and the soil deformations of geotextile reinforced slopes were evaluated with Particle Image Velocimetry (PIV). The experimental results showed that failure of the centrifuge models initiated at midheight of the slope, and occurred due to geotextile breakage instead of pullout. The location of the shear surface is independent of the tensile strength of the geotextile; it is dependent on the shear strength of the soil. It is logical to see that the required acceleration of the centrifuge at slope failure was decreased with increasing slope inclination. An important contribution to the stability of the slope models was provided by the overlapping of the geotextile layers. It has a secondary reinforcement effect when it was prolonged and passed through the shear surface. Moreover, the location of the shear surface observed with PIV analysis exactly matches the tears of the retrieved geotextiles measured carefully after the centrifuge testing. It is concluded that PIV is an efficient tool to instrument the slope failures in a geotechnical centrifuge.(author) [de

Measurement of gas permeability through geo-synthetic clay liners; Mesure de la permeabilite au gaz a travers des geosynthetiques bentonitiques

Energy Technology Data Exchange (ETDEWEB)

Bouazza, A.; Vangpaisal, T. [Monash University, Melbourne, Victoria (Australia)

2000-07-01

While much research has been performed to investigate the ability of GCLs to limit flow through minimization of the saturated hydraulic conductivity, very little is known about their capabilities to control gas flux and therefore reducing gas migration into the atmosphere or the areas surrounding landfills. The aim of this study was to assess gas flow through GCLs with a simple and reliable testing procedure. A gas permeameter was developed to study gas flow through partially saturated geo-synthetic clay liners (GCLs). Measurements of the differential pressure across the GCL sample at varying flow rates were used to calculate gas permeability at different moisture contents. For the range of water content studied (65% < {omega} < 128%) a decrease of around 4 orders of magnitude in the GCL permeability has been observed. This suggests that the GCL degree of hydration during the design life of a waste containment facility is an important issue to address in the design process of a lining or cover system using a GCL. (authors)

In-situ studies on the performance of landfill caps (compacted soil liners, geomembranes, geosynthetic clay liners, capillary barriers)

International Nuclear Information System (INIS)

Melchior, S.

1997-01-01

Since 1986 different types of landfill covers have been studied in-situ on the Georgswerder landfill in Hamburg, Germany. Water balance data are available for eight years. The performance of different carriers has been measured by collecting the leakage on areas ranging from 100 m 2 to 500 m 2 . Composite liners with geomembranes performed best, showing no leakage. An extended capillary barrier also performed well. The performance of compacted soil liners, however, decreased severely within five years due to desiccation, shrinkage and plant root penetration (liner leakage now ranging from 150 mm/a to 200 mm/a). About 50 % of the water that reaches the surface of the liner is leaking through it. The maximum leakage rates have increased from 2 x 10 -10 m 3 m -2 s -1 to 4 x 10 -8 m 3 m -2 s -1 . Two types of geosynthetic clay liners (GCL) have been tested for two years now with disappointing results. The GCL desiccated during the first dry summer of the study. High percolation rates through the GCL were measured during the following winter (45 mm resp. 63 mm in four months). Wetting of the GCL did not significantly reduce the percolation rates

Improved isolation of cadmium from paddy soil by novel technology based on pore water drainage with graphite-contained electro-kinetic geosynthetics.

Science.gov (United States)

Tang, Xianqiang; Li, Qingyun; Wang, Zhenhua; Hu, Yanping; Hu, Yuan; Scholz, Miklas

2018-03-10

Novel soil remediation equipment based on electro-kinetic geosynthetics (EKG) was developed for in situ isolation of metals from paddy soil. Two mutually independent field plot experiments A and B (with and without electric current applied) were conducted. After saturation using ferric chloride (FeCl 3 ) and calcium chloride (CaCl 2 ), soil water drainage capacity, soil cadmium (Cd) removal performance, energy consumption as well as soil residual of iron (Fe) and chloride (Cl) were assessed. Cadmium dissolved in the soil matrix and resulted in a 100% increase of diethylenetriamine-pentaacetic acid (DTPA) extracted phyto-available Cd. The total soil Cd content reductions were 15.20% and 26.58% for groups A and B, respectively, and electric field applications resulted in a 74.87% increase of soil total Cd removal. The electric energy consumption was only 2.17 kWh/m 3 for group B. Drainage by gravity contributed to > 90% of the overall soil dewatering capacity. Compared to conventional electro-kinetic technology, excellent and fast soil water drainage resulted in negligible hydrogen ion (H + ) and hydroxide ion (OH - ) accumulation at nearby electrode zones, which addressed the challenge of anode corrosion and cathode precipitation of soil metals. External addition of FeCl 3 and CaCl 2 caused soil Fe and Cl residuals and led to 4.33-7.59% and 139-172% acceptable augments in soil total Fe and Cl content, correspondingly, if compared to original untreated soils. Therefore, the novel soil remediation equipment developed based on EKG can be regarded as a promising new in situ technology for thoroughly isolating metals from large-scale paddy soil fields.

Development of kenaf mat for slope stabilization

Science.gov (United States)

Ahmad, M. M.; Manaf, M. B. H. Ab; Zainol, N. Z.

2017-09-01

This study focusing on the ability of kenaf mat to act as reinforcement to laterite compared to the conventional geosynthetic in term of stabilizing the slope. Kenaf mat specimens studied in this paper are made up from natural kenaf fiber with 3mm thickness, 150mm length and 20mm width. With the same size of specimens, geosynthetic that obtain from the industry are being tested for both direct shear and tensile tests. Plasticity index of the soil sample used is equal to 13 which indicate that the soil is slightly plastic. Result shows that the friction angle of kenaf mat is higher compared to friction between soil particles itself. In term of resistance to tensile load, the tensile strength of kenaf mat is 0.033N/mm2 which is lower than the tensile strength of geosynthetic.

Tests for the characterization of bentonite used in the manufacture of clay geo synthetic barriers (GBR-C)

International Nuclear Information System (INIS)

Leiro, A.; Mateo, B.; Garcia, H.; Llorente, S.

2011-01-01

Bentonites are clays essentially composed of the smectite minerals. they are used in the manufacture of Clay Geosynthetic Barriers )GBR-C) which are low-permeability geosynthetic materials, forming part of the lining technologies and construction waterproofing systems. This article shows a series of testing to evaluate the quality of the bentonite for such use. Correlation between different testing has also been established in order to identify the most suitable ones for their characterization. (Author) 8 refs.

Production of polyol carbonates and their intercalation into Smectite clays

OpenAIRE

Shaheen, Uzma

2017-01-01

In hyper-saline conditions, clays in geosynthetic clay liners contract and fail to form a hydraulic barrier due to removal of water from the interlayer spaces of smectite, which is the swelling mineral component of bentonites used in geosynthetic clay liners. Five-membered cyclic carbonates such as propylene carbonate have been reported to form stable intercalated complexes with hydrated Na-smectite, which maintain swollen states at 1M). Glycerol carbonate was selected as an alternative c...

Evolution of the Stability Work from Classic Retaining Walls to Mechanically Stabilized Earth Walls

Directory of Open Access Journals (Sweden)

Anghel Stanciu

2008-01-01

Full Text Available For the consolidation of soil mass and the construction of the stability works for roads infrastructure it was studied the evolution of these kinds of works from classical retaining walls - common concrete retaining walls, to the utilization in our days of the modern and competitive methods - mechanically stabilized earth walls. Like type of execution the variety of the reinforced soil is given by the utilization of different types of reinforcing inclusions (steel strips, geosynthetics, geogrids or facing (precast concrete panels, dry cast modular blocks, metal sheets and plates, gabions, and wrapped sheets of geosynthetics.

Shear strength behavior of geotextile/geomembrane interfaces

Directory of Open Access Journals (Sweden)

Belén M. Bacas

2015-12-01

Full Text Available This paper aims to study the shear interaction mechanism of one of the critical geosynthetic interfaces, the geotextile/geomembrane, typically used for lined containment facilities such as landfills. A large direct shear machine is used to carry out 90 geosynthetic interface tests. The test results show a strain softening behavior with a very small dilatancy (<0.5 mm and nonlinear failure envelopes at a normal stress range of 25–450 kPa. The influences of the micro-level structure of these geosynthetics on the macro-level interface shear behavior are discussed in detail. This study has generated several practical recommendations to help professionals to choose what materials are more adequate. From the three geotextiles tested, the thermally bonded monofilament exhibits the best interface shear strength under high normal stress. For low normal stress, however, needle-punched monofilaments are recommended. For the regular textured geomembranes tested, the space between the asperities is an important factor. The closer these asperities are, the better the result achieves. For the irregular textured geomembranes tested, the nonwoven geotextiles made of monofilaments produce the largest interface shear strength.

Spanish experience in the use of synthetic geo membranes for hydraulic works

International Nuclear Information System (INIS)

Blanco Fernandez, M.; Leiro Lopez, A.

2014-01-01

The Spanish institution Centro de Estudios y Experimentacion de Obras Publicas (CEDEX) has studied for decades the behaviour of geosynthetic products, specially the polymeric geosynthetic barriers used as waterprofing systems of different hydraulic works, mainly in reservoirs. Both in geotextiles or related products and in geomembranes, initial characteristics are determined; besides of that, periodic controls along the service life are performers in geomembranes. The monitoring of more than two hundred hydraulic structure hydraulic structures requires technical inspection, taking samples and replacing them, experimental tests and recommendations, with the purpose of increasing security and durability in hydraulic structures. Because of that, the Spanish experience in this field of technology is presented along this paper. (Author)

Evaluation of the base/subgrade soil under repeated loading : phase II, in-box and ALF cyclic plate load tests [tech summary].

Science.gov (United States)

2012-03-01

The inadequacy of many existing roads due to rapid growth in traffic volume provides a motivation for exploring alternatives to : existing methods of constructing and rehabilitating roads. The use of geosynthetics to stabilize and reinforce paved and...

Evaluating the benefits of geogrid reinforced bases in flexible pavement : technical summary report.

Science.gov (United States)

2009-09-01

The inadequacy of many existing roads due to rapid growth in traffic volume provides a motivation for exploring alternatives to existing methods of constructing and rehabilitating roads. The use of geosynthetics to stabilize and reinforce paved and u...

Shear strength behaviour of geosynthetics

OpenAIRE

Martínez Bacas, Ana Belén

2010-01-01

RESUMEN: El estudio de los parámetros resistentes de los geosintéticos utilizados en los sistemas de impermeabilización de vertederos es un tema muy importante. Estos sistemas contienen diferentes interfaces (geosintético/geosintético y/o suelo/geosintético), muchas de las cuales tienen baja resistencia al deslizamiento. Esto potencia la existencia de superficies de rotura a lo largo de los taludes de los vertederos. El conocimiento de los parámetros resistentes al corte de los contactos ...

Geotextiles: composition, applications and ecotoxicology

NARCIS (Netherlands)

Wiewel, B.V.; Lamoree, M.H.

2016-01-01

Geosynthetics is the umbrella term for thin, flexible material sheets applied in civil and environmental engineering, of which geotextiles form the largest group. Most geotextiles consist of a polymer from the polyolefin, polyester or polyamide family, and additives to improve their stability. The

Folosirea pământului armat la fundaţii pe terenuri slabe

Directory of Open Access Journals (Sweden)

Felicia Enache Niculescu

2011-06-01

Full Text Available The geosynthetics term is generally regarded to encompass eight main product categories: geotextiles, geogrids, geonets, geomembranes, geocomposites, geocells and combinations of materiales. These synthetic polymeric can be fabricated from hight resistences, deformation needetand a good adherence with earth confinement.

Fluid migration through geo-membrane seams and through the interface between geo-membrane and geo-synthetic clay liner

International Nuclear Information System (INIS)

Barroso, M.

2005-03-01

Composite liners are used to limit the contamination migration from landfills. Their successful performance is closely related with the geo-membrane as it provides the primary barrier to diffusive and advective transport of contaminants. Critical issues on the performance of the geo-membranes are the seams between geo-membrane panels and the inevitable defects resulting, for instance, from inadequate installation activities. In landfills, where high density polyethylene geo-membranes are usually used, seams are typically made by the thermal-hot dual wedge method. A literature review on quality control of the seams showed that, in situ, fluid-tightness of seams is evaluated in qualitative terms (pass/failure criteria), despite their importance to ensure appropriate performance of the geo-membranes as barriers. In addition, a synthesis of studies on geo-membrane defects indicated that defects varying in density from 0.7 to 15.3 per hectare can be found in landfills. Defects represent preferential flow paths for leachate. Various authors have developed analytical solutions and empirical equations for predicting the flow rate through composite liners due to defects in the geo-membrane. The validity of these methods for composite liners comprising a geo-membrane over a geo-synthetic clay liner (GCL) over a compacted clay liner (CCL) has never been studied from an experimental point of view. To address the problem of fluid migration through the geo-membrane seams, an attempt is made to provide a test method, herein termed as 'gas permeation pouch test', for assessing the quality of the thermal-hot dual wedge seams. This test consists of pressurizing the air channel formed by the double seam with a gas to a specific pressure and, then, measuring the decrease in pressure over time. From the pressure decrease, both the gas permeation coefficients, in steady state conditions, and the time constant, in unsteady state conditions, can be estimated. Experiments were carried out

Geotextiles in Flexible Pavement Construction

Science.gov (United States)

Alungbe, Gabriel D.

2004-01-01

People everywhere in the developed world regularly drive on paved roads. Learning about the construction techniques and materials used in paving benefits technology and construction students. This article discusses the use of geosynthetic textiles in pavement construction. It presents background on pavements and describes geotextiles and drainage…

Gas permeability of bentonite barriers: development, construction and testing of a measurement system

Directory of Open Access Journals (Sweden)

Heraldo Nunes Pitanga

Full Text Available Abstract This article proposes a testing device to quickly and reliably estimate the gas permeability of bentonite-based clay barriers used in landfill cover systems. The testing methodology is based on a transient gas flow regime that passes through the barrier, therefore not requiring the use of sophisticated equipment that aim to maintain constant differential pressure and measure the gas flow, common requirements for testing methods under a permanent flow regime. To confirm the feasibility of the proposed technique, tests were performed on a pure hydrated bentonite layer, which subsequently encompassed samples of geosynthetic clay liner (GCL at different moisture contents. Geosynthetic clay liners are often selected as a part of the barrier layer for cover systems in solid waste landfills to prevent infiltration of rainfall and migration of biogas into the atmosphere. The results confirmed the equipment reliability and differentiate the different responses of the gas flow barriers studied, considering their different compositions and different moistures.

State-of-the-art synthetic membrane for capping landfills

International Nuclear Information System (INIS)

Kriofske, K.P.; Gagle, D.W.

1991-01-01

Very Low Density Polyethylene (VLDPE) has emerged as a superior capping material for landfill closures. Landfills must be capped by a material which will undergo substantial deformation in areas of localized settlement prior to rupture. Methane and hydrogen sulfide gases must be contained and directed to collection points without permeating the landfill cap. Vegetative growth in the cover sods will be protected by the gas impermeability of the geosynthetic membrane. VLDPE compounded with carbon black is minimally affected by radiation and is inert to ultraviolet rays. This property sustains VLDPE's ability to retard gas permeation at levels superior to other geosynthetics. Cover soil stability on long cap slopes in all weather conditions is crucial. It has been demonstrated in the laboratory and in full-scale, on-site test conditions that VLDPE exhibits friction characteristics equaling or exceeding other synthetics used for this purpose without diminishing physical and chemical properties. Large-scale, multiaxial stress tests have demonstrated the ability of VLDPE to deflect substantially in all directions of a potential settlement area. Only PVC can equal the elastic deformation properties of VLDPE, but PVC is more gas-permeable susceptible to degradation due to natural soil radiation or ultraviolet light and heat. Test results are presented to illustrate these points. The geosynthetic cap membrane must prevent water percolation into the landfill to prevent the formation of hazardous leachates. The use of a VLDPE cap reduces the depth of cap soils, thus increasing landfill volume. The economics and reduction in long-term liabilities of closure costs are enhanced by the use of VLDPE in the cap system. Since the expected half-life of polyethylene exceeds hundreds of years, the inclusion of VLDPE in the cap system will provide pollution security for many generations

Conceptual model for reinforced grass on inner dike slopes

NARCIS (Netherlands)

Verhagen, H.J.; ComCoast

2005-01-01

A desk study has been carried out in order to develop a conceptual model for the erosion of inner dike slopes with reinforced grass cover. Based on the results the following can be concluded: The presence of a geosynthetic in a grass slope can be taken into account in the EPM method by increasing

Implementation and verification of interface constitutive model in FLAC3D

Directory of Open Access Journals (Sweden)

Hai-min Wu

2011-09-01

Full Text Available Due to the complexity of soil-structure interaction, simple constitutive models typically used for interface elements in general computer programs cannot satisfy the requirements of discontinuous deformation analysis of structures that contain different interfaces. In order to simulate the strain-softening characteristics of interfaces, a nonlinear strain-softening interface constitutive model was incorporated into fast Lagrange analysis of continua in three dimensions (FLAC3D through a user-defined program in the FISH environment. A numerical simulation of a direct shear test for geosynthetic interfaces was conducted to verify that the interface model was implemented correctly. Results of the numerical tests show good agreement with the results obtained from theoretical calculations, indicating that the model incorporated into FLAC3D can simulate the nonlinear strain-softening behavior of interfaces involving geosynthetic materials. The results confirmed the validity and reliability of the improved interface model. The procedure and method of implementing an interface constitutive model into a commercial computer program also provide a reference for implementation of a new interface constitutive model in FLAC3D.

Proceedings (of the) first Canadian conference on environmental geotechnics. Comptes-rendus (de la) premiere conference canadienne de geotechnique environnementale

Energy Technology Data Exchange (ETDEWEB)

Chapuis, R P; Aubertin, M

1991-01-01

A conference was held to discuss responses to increasing soil and groundwater contamination. Papers were presented in the areas of regulations and guidelines, design, management and performance of sites, clay, soil-bentonite and geosynthetic barriers, hydrogeology, geochemistry and fate of contaminants, contaminated sites exploration and rehabilitation, leachate generation and treatment, and modelling and geostatistics. Separate abstracts have been prepared for 22 papers presented at the conference.

The role of geotextiles in geosynthetic applications

CSIR Research Space (South Africa)

Anandjiwala, RD

2013-11-01

Full Text Available , is required. Needlepunched nonwoven geotextiles are extensively used in civil engineering applications, including road and railway construction, landfills, land reclamation, sea defence, and reinforcement of clay slopes. Such applications require geotextiles...

Low cost friction seismic base-isolation of residential new masonry buildings in developing countries: A small masonry house case study

Science.gov (United States)

Habieb, A. B.; Milani, G.; Tavio, T.; Milani, F.

2017-07-01

A Finite element model was established to examine performance of a low-cost friction base-isolation system in reducing seismic vulnerability of rural buildings. This study adopts an experimental investigation of the isolation system which was conducted in India. Four friction isolation interfaces, namely, marble-marble, marble-high-density polyethylene, marble-rubber sheet, and marble-geosynthetic were involved. Those interfaces differ in static and dynamic friction coefficient obtained through previous research. The FE model was performed based on a macroscopic approach and the masonry wall is assumed as an isotropic element. In order to observe structural response of the masonry house, elastic and plastic parameters of the brick wall were studied. Concrete damage plasticity (CDP) model was adopted to determine non-linear behavior of the brick wall. The results of FE model shows that involving these friction isolation systems could much decrease response acceleration at roof level. It was found that systems with marble-marble and marble-geosynthetic interfaces reduce the roof acceleration up to 50% comparing to the system without isolation. Another interesting result is there was no damage appearing in systems with friction isolation during the test. Meanwhile a severe failure was clearly visible for a system without isolation.

Train induced vibrations in geosynthetic reinforced railway embankments

DEFF Research Database (Denmark)

Zania, Varvara; Hededal, Ole; Krogsbøll, Anette

2011-01-01

to accomplish the aforementioned research goals, dynamic finite element analyses of two-dimensional plane strain models have been performed. The results of the adopted approach, which is rather simplified, were compared with the corresponding results reported in the literature for a real scale experiment...

Effects of Geofoam Panels on Static Behavior of Cantilever Retaining Wall

OpenAIRE

Navid Hasanpouri Notash; Rouzbeh Dabiri

2018-01-01

Geofoam is one of the geosynthetic products that can be used in geotechnical applications. According to researches, expanded polystyrene (EPS) geofoam placed directly against a rigid retaining wall has been proposed as a strategy to reduce static loads on the wall. This study employed a finite difference analysis using a 2-D FLAC computer program by considering yielding and nonyielding states for retaining walls to explore the effectiveness of geofoam panels in improving the static performanc...

Characterization of infiltration rates from landfills: supporting groundwater modeling efforts.

Science.gov (United States)

Moo-Young, Horace; Johnson, Barnes; Johnson, Ann; Carson, David; Lew, Christine; Liu, Salley; Hancocks, Katherine

2004-01-01

The purpose of this paper is to review the literature to characterize infiltration rates from landfill liners to support groundwater modeling efforts. The focus of this investigation was on collecting studies that describe the performance of liners 'as installed' or 'as operated'. This document reviews the state of the science and practice on the infiltration rate through compacted clay liner (CCL) for 149 sites and geosynthetic clay liner (GCL) for 1 site. In addition, it reviews the leakage rate through geomembrane (GM) liners and composite liners for 259 sites. For compacted clay liners (CCL), there was limited information on infiltration rates (i.e., only 9 sites reported infiltration rates.), thus, it was difficult to develop a national distribution. The field hydraulic conductivities for natural clay liners range from 1 x 10(-9) cm s(-1) to 1 x 10(-4) cm s(-1), with an average of 6.5 x 10(-8) cm s(-1). There was limited information on geosynthetic clay liner. For composite lined and geomembrane systems, the leak detection system flow rates were utilized. The average monthly flow rate for composite liners ranged from 0-32 lphd for geomembrane and GCL systems to 0 to 1410 lphd for geomembrane and CCL systems. The increased infiltration for the geomembrane and CCL system may be attributed to consolidation water from the clay.

Diseño de un pavimento utilizando geomallas en tramo de la carretera bajada de chanduy – aguas verdes - pocito (absc. 2+900 hasta absc. 3+600)

OpenAIRE

Tapia Diez, Andrés Renato; Barona Fajardo, Fabricio Eduardo; Inga Morán, Luis Rolando; Santos Baquerizo, Eduardo

2009-01-01

This seminar graduation thesis is based on the design of a piece of the road “Bajada de Chanduy - Aguas Verdes – Pocito” using synthetic net materials that improve the structural capacity of a pavement. The mentioned piece of road starts from the abscissa 2+900 to the 3+600 and presents a low support capacity for which is necessary the use of the geosynthetic net. Primarily it is shown the AASHTO design methodology for pavements in order to compare the design thickness obtained...

MATERIALS FOR THE FINAL COVER OF SANITARY LANDFILLS

OpenAIRE

Davorin Kovačić

1994-01-01

The paper deals with the selection of materials for the sea¬ling layer in the final cover of sanitary landfills. The sealing la¬yer is the most critical component of the final cover. Its role is to minimize percolation of water through the final cover. Ma¬terials used for the construction of the sealing layer are either of mineral origin (compacted clay) or geosynthetic (geomem¬brane). They are most often used in combination creating com¬posite liners. Recently alternative materials are also ...

488-1D Ash Basin closure cap help modeling- Microdrain® liner option

Energy Technology Data Exchange (ETDEWEB)

Dyer, J. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-08-03

At the request of Area Completion Engineering and in support of the 488-1D Ash Basin closure, the Savannah River National Laboratory (SRNL) performed hydrologic simulations of the revised 488-1D Ash Basin closure cap design using the Hydrologic Evaluation of Landfill Performance (HELP) model. The revised design substitutes a MicroDrain Liner®—60-mil low-density polyethylene geomembrane structurally integrated with 130-mil drainage layer—for the previously planned drainage/barrier system—300-mil geosynthetic drainage layer (GDL), 300-mil geosynthetic clay liner (GCL), and 6-inch common fill soil layer. For a 25-year, 24-hour storm event, HELP model v3.07 was employed to (1) predict the peak maximum daily hydraulic head for the geomembrane layer, and (2) ensure that South Carolina Department of Health and Environmental Control (SCDHEC) requirements for the barrier layer (i.e., ≤ 12 inches hydraulic head on top of a barrier having a saturated hydraulic conductivity ≤ 1.0E-05 cm/s) will not be exceeded. A 25-year, 24-hour storm event at the Savannah River Site (SRS) is 6.1 inches rainfall (Weber 1998). HELP model v3.07 results based upon the new planned cap design suggest that the peak maximum daily hydraulic head on the geomembrane barrier layer will be 0.15 inches for a minimum slope equal to 3%, which is two orders of magnitude below the SCDHEC upper limit of 12 inches.

488-1D Ash basin closure cap help modeling-Microdrain® liner option

Energy Technology Data Exchange (ETDEWEB)

Dyer, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-09-06

At the request of Area Completion Engineering and in support of the 488-1D Ash Basin closure, the Savannah River National Laboratory (SRNL) performed hydrologic simulations of the revised 488-1D Ash Basin closure cap design using the Hydrologic Evaluation of Landfill Performance (HELP) model. The revised design substitutes a MicroDrain Liner®—50-mil linear low-density polyethylene geomembrane structurally integrated with 130-mil drainage layer—for the previously planned drainage/barrier system—300-mil geosynthetic drainage layer (GDL), 300-mil geosynthetic clay liner (GCL), and 6-inch common fill soil layer. For a 25-year, 24-hour storm event, HELP model v3.07 was employed to (1) predict the peak maximum daily hydraulic head for the geomembrane layer, and (2) ensure that South Carolina Department of Health and Environmental Control (SCDHEC) requirements for the barrier layer (i.e., ≤ 12 inches hydraulic head on top of a barrier having a saturated hydraulic conductivity ≤ 1.0E-05 cm/s) will not be exceeded. A 25-year, 24-hour storm event at the Savannah River Site (SRS) is 6.1 inches rainfall (Weber 1998). HELP model v3.07 results based upon the new planned cap design suggest that the peak maximum daily hydraulic head on the geomembrane barrier layer will be 0.179 inches for a minimum slope equal to 3%, which is approximately two orders of magnitude below the SCDHEC upper limit of 12 inches.

Seismic Stability of Reinforced Soil Slopes

DEFF Research Database (Denmark)

Tzavara, I.; Zania, Varvara; Tsompanakis, Y.

2012-01-01

Over recent decades increased research interest has been observed on the dynamic response and stability issues of earth walls and reinforced soil structures. The current study aims to provide an insight into the dynamic response of reinforced soil structures and the potential of the geosynthetics...... to prevent the development of slope instability taking advantage of their reinforcing effect. For this purpose, a onedimensional (SDOF) model, based on Newmark’s sliding block model as well as a two-dimensional (plane-strain) dynamic finite-element analyses are conducted in order to investigate the impact...

Assessment of reinforced slopes instability in view of semi-analytical methods

DEFF Research Database (Denmark)

Tzavara, I.; Tsompanakis, Y.; Zania, Varvara

The stabilization of natural or man-made earth slopes is usually achieved via proper reinforcement, which usually comprises of geosynthetic geogrids. On the other hand, earthquakes impose in such geostructures dynamic stresses, which may be excessive and can lead to accumulation of slip...... structures. Two approaches were adopted for the analysis of the dynamic stability in order to analyze the conservativeness of the employed method. Firstly, the dynamic response of the sliding soil mass and the development of the seismic accumulated slippage are taken into account simultaneously in a so...

ASSESSMENT OF EARTHQUAKE HAZARDS ON WASTE LANDFILLS

DEFF Research Database (Denmark)

Zania, Varvara; Tsompanakis, Yiannis; Psarropoulos, Prodromos

Earthquake hazards may arise as a result of: (a) transient ground deformation, which is induced due to seismic wave propagation, and (b) permanent ground deformation, which is caused by abrupt fault dislocation. Since the adequate performance of waste landfills after an earthquake is of outmost...... importance, the current study examines the impact of both types of earthquake hazards by performing efficient finite-element analyses. These took also into account the potential slip displacement development along the geosynthetic interfaces of the composite base liner. At first, the development of permanent...

Enhanced shear strength of sodium bentonite using frictional additives

International Nuclear Information System (INIS)

Schmitt, K.E.; Bowders, J.J.; Gilbert, R.B.; Daniel, D.E.

1997-01-01

One of the most important obstacles to using geosynthetic clay liners (GCLs) in landfill cover systems is the low shear strength provided by the bentonitic portion of the GCL. In this study, the authors propose that granular, frictional materials might be added to the bentonite to form an admixture that would have greater shear strength than the bentonite alone while still raining low hydraulic conductivity. Bentonite was mixed with two separate granular additives, expanded shale and recycled to form mixtures consisting of 20-70% bentonite by weight. In direct shear tests at normal stresses of 34.5-103.5 kPa, effective friction angles were measured as 45 degrees for the expanded 36 degrees for the recycled glass, and 7 degrees for the hydrated granular bentonite. The strength of the expanded shale mixtures increased nearly linearly as the percentage shale in the mixture increased, to 44 degrees for a bentonite mixture with 80% shale. The addition of recycled glass showed little effect on the shear strength of the mixtures of glass and bentonite. Hydraulic conductivity measurements for both types of mixtures indicated a linear increase with log(k) as the amount of granular additive increased. For applications involving geosynthetic clay liners for cover systems, a mixture of 40% expanded shale and 60% bentonite is recommended, although further testing must be done. The 40/60 mixture satisfies the hydraulic equivalency requirement, with k = 5.1X10 -9 cm/sec, while increasing the shear strength parameters of the bentonitic mixture to φ' = 17 degrees and c' = 0

MATERIALS FOR THE FINAL COVER OF SANITARY LANDFILLS

Directory of Open Access Journals (Sweden)

Davorin Kovačić

1994-12-01

Full Text Available The paper deals with the selection of materials for the sea¬ling layer in the final cover of sanitary landfills. The sealing la¬yer is the most critical component of the final cover. Its role is to minimize percolation of water through the final cover. Ma¬terials used for the construction of the sealing layer are either of mineral origin (compacted clay or geosynthetic (geomem¬brane. They are most often used in combination creating com¬posite liners. Recently alternative materials are also used like paper mill sludge or discarded swelling clay.

Research Progress of Building Materials Used in Construction Land

Science.gov (United States)

Niu, Yan

2018-01-01

Construction land preparation is an important aspect of land remediation project. The research of materials in the process of land improvement is the foundation and the core. Therefore, it is necessary to study the materials that may be involved in the process of building land preparation. In this paper, the research on the construction materials such as recycled concrete, geosynthetics, soil stabilizers, soil improvers, building insulation materials and inorganic fibrous insulation materials, which are commonly used in construction sites, is reviewed and discussed in this paper. Land remediation project involved in the construction of land materials to provide reference.

M-area basin closure-Savannah River Site

International Nuclear Information System (INIS)

McMullin, S.R.; Horvath, J.G.

1991-01-01

M-Area, on the Savannah River Site, processes raw materials and manufactures fuel and target rods for reactor use. Effluent from these processes were discharged into the M-Area settling basin and Lost Lake, a natural wetland. The closure of this basin began in 1988 and included the removal and stabilization of basin fluids, excavation of all contaminated soils from affected areas and Lost Lake, and placement of all materials in the bottom of the emptied basin. These materials were covered with a RCRA style cap, employing redundant barriers of kaolin clay and geosynthetic material. Restoration of excavated uplands and wetlands is currently underway

Analysis of geosynthetic tubes filled with several liquids with different densities

Czech Academy of Sciences Publication Activity Database

Malík, Josef; Sysala, Stanislav

2010-01-01

Roč. 29, - (2010), s. 249-256 ISSN 0266-1144 R&D Projects: GA ČR GA103/08/1700 Institutional research plan: CEZ:AV0Z30860518 Keywords : geosyntetic tube * rigid horizontal foundation * numerical modelling Subject RIV: BA - General Mathematics Impact factor: 2.590, year: 2010 www.elsevier.com/locate/geotexmen, doi:10.1016/j.geotexmen.2010.11.004

Analysis of geosynthetic tubes filled with several liquids with different densities

Czech Academy of Sciences Publication Activity Database

Malík, Josef; Sysala, Stanislav

2011-01-01

Roč. 29, č. 3 (2011), s. 249-256 ISSN 0266-1144 R&D Projects: GA ČR GA103/08/1700 Institutional research plan: CEZ:AV0Z30860518 Keywords : geosyntetic tube * rigid horizontal foundation * numerical modelling Subject RIV: BA - General Mathematics Impact factor: 2.036, year: 2011 http://www.sciencedirect.com/science/article/pii/S0266114410001214

Spanish experience in the use of synthetic geo membranes for hydraulic works; Experiencia espanola en el uso de geomembranas sinteticas en obras hidraulicas

Energy Technology Data Exchange (ETDEWEB)

Blanco Fernandez, M.; Leiro Lopez, A.

2014-02-01

The Spanish institution Centro de Estudios y Experimentacion de Obras Publicas (CEDEX) has studied for decades the behaviour of geosynthetic products, specially the polymeric geo synthetic barriers used as waterproofing systems of different hydraulic works, mainly in reservoirs. Both in geotextiles or related products and in geomembranes, initial characteristics are determined; besides of that, periodic controls along the service life are performers in geomembranes. The monitoring of more than two hundred hydraulic structure hydraulic structures requires technical inspection, taking samples and replacing them, experimental tests and recommendations, with the purpose of increasing security and durability in hydraulic structures. Because of that, the Spanish experience in this field of technology is presented along this paper. (Author)

Cover systems in the Athabasca oil sands : a summary of the Green Bullet and ten years of reclamation research at Syncrude Canada Ltd.

Energy Technology Data Exchange (ETDEWEB)

O' Kane, M. [O' Kane Consultants Inc., Calgary, AB (Canada)

2010-02-15

This PowerPoint presentation discussed the use of a dry cover system over oil sand tailings as land reclamation strategy. Dry covers can range from a single layer of earthen material to several layers of different material types, including native soils, non-reactive tailings or waste rock, geosynthetic materials, and oxygen consuming organic materials. The 3 prototype covers used in the Athabasca deposit in northern Alberta include peat, glacial till and sedge-sphagnum open bog (SSOB). The hydraulic role of the covers was described. This presentation also described how the physical reclamation works, with particular reference to how the area is contoured to ensure proper drainage. Soil and vegetation assessments are undertaken to ensure the reclamation amendments are achieving the goals of the reclamation plan. tabs., figs.

Selection of Liner Materials and Design of Hazardous Water Facilities in Saudi Arabia

Directory of Open Access Journals (Sweden)

Sahel N. Abduljauwad

2001-12-01

Full Text Available Rapid development in Saudi Arabia has produced a broad spectrum of wastes.  In the last two decades, several refineries and petrochemical industries have been established. These industries have produced sludges and other toxic wastes which need proper planning for their handling and disposal. This paper covers design and selection of liner materials for two hazardous waste disposal sites. One of them is located in the Eastern Province of Saudi Arabia, while the second one is located in the Western part. The paper will present complete design details of the natural compacted and geosynthetic soil liners and the leachate collection and removal system for primary liners and leak detection/leachate collection and removal system for secondary liners.

Cover systems in the Athabasca oil sands : a summary of the Green Bullet and ten years of reclamation research at Syncrude Canada Ltd

International Nuclear Information System (INIS)

O'Kane, M.

2010-01-01

This PowerPoint presentation discussed the use of a dry cover system over oil sand tailings as land reclamation strategy. Dry covers can range from a single layer of earthen material to several layers of different material types, including native soils, non-reactive tailings or waste rock, geosynthetic materials, and oxygen consuming organic materials. The 3 prototype covers used in the Athabasca deposit in northern Alberta include peat, glacial till and sedge-sphagnum open bog (SSOB). The hydraulic role of the covers was described. This presentation also described how the physical reclamation works, with particular reference to how the area is contoured to ensure proper drainage. Soil and vegetation assessments are undertaken to ensure the reclamation amendments are achieving the goals of the reclamation plan. tabs., figs.

Stability analysis criteria in landfill design based on the Spanish code

International Nuclear Information System (INIS)

Estaire Gepp, J.; Pardo de Santayana, F.

2014-01-01

The design of a landfill requires performing stability analyses. To perform such analyses it is necessary to define different design situations and their corresponding safety factors. Geo synthetics are normally used to construct the lining system of the landfills, causing critical slip surfaces to pass along one of the different geosynthetic interfaces. Determination of the shear strength of such critical interfaces is, therefore, an extremely important issue. In this paper, these aspects are analysed based on what is set in the Spanish codes and in the technical literature. As a result of the study, some tables are presented which relate the different design situations (normal, accidental or extraordinary) to the shear strength of the lining system to be used (peak or residual) and define the minimum factor of safety to be accomplished. (Author)

Stability Analysis and Stabilization of Miduk Heap Leaching Structure, Iran

Directory of Open Access Journals (Sweden)

Mehdi Amini

2013-06-01

Full Text Available To construct copper heap leaching structures, a stepped heap of ore is placed over an isolated sloping surface and then washed with sulphuric acid. The isolated bed of such a heap consists of some natural and geosynthetic layers. Shear strength parameters between these layers are low, so they form the possible sliding surfaces of the heaps. Economic and environmental considerations call for studying such slides. In this study, firstly, results of the laboratory tests carried on the materials of the heap leaching structures bed are presented. Then, the instability mechanisms of such structures are investigated and proper approaches are summarized for their stabilization. Finally, stability of the Miduk copper heap is evaluated as a case history, and appropriate approaches and their effects are discussed for its stabilization.

Electrokinetic Stabilisation Method of Soft Clay in Pure System using Electrokinetic Geosynthetic Electrode

Science.gov (United States)

Azhar, A. T. S.; Jefferson, I.; Madun, A.; Abidin, M. H. Z.; Rogers, C. D. F.

2018-04-01

Electrokinetic stabilisation (EKS) method has the ability to solve the problems of soft highly compressibility soil. This study will present the results from an experimental study of EKS on soft soils using inactive kaolinite clay, inert electrode and distilled water (DW) as a pure system mechanism before any chemical stabilisers being used in this research. Therefore, this will provide a baseline study to improve the efficiency of EKS approach. The test model was using inert electrode of Electrokinetic Geosythentic (EKG) developed at the Newcastle University to apply a constant voltage gradient of 50 V/m across a soil sample approximately 400 mm. Distilled water was used at the pore electrolyte fluid compartments supplied under zero hydraulic gradient conditions for the periods of 3, 7 and 14 days. Throughout the monitoring, physical and chemical characteristics were measured. Results from the monitoring data, physical and chemical properties of the pure system showed the development of pH gradient, the changes of electrical conductivity and chemical concentrations with regards to the distance from anode and treatment periods due to the electrochemical effects even though there was no chemical stabilisers were introduced or released from the degradation of electrodes.

LABORATORY TESTING OF BENTONITE CLAYS FOR LANDFILL DESIGN AND CONSTRUCTION

Directory of Open Access Journals (Sweden)

Biljana Kovačević Zelić

2007-12-01

Full Text Available Top and bottom liners are one of the key construction elements in every landfill. They are usually made as compacted clay liners (CCLs composed of several layers of compacted clay with strictly defined properties or by the use of alternative materials such as: GCL – geosynthetic clay liner, BES – bentonite enhanced soils or bentonite/polymer mixtures. Following the state of the art experiences in the world, GCLs are used in Croatian landfills for several years, as well. Depending upon the location and the obeying function, GCLs have to fulfill certain conditions. A legislated compatibility criterion has to be proven by various laboratory tests. In the paper are presented the results of direct shear and chemical compatibility tests of GCLs as well as the results of permeability measurement of kaolin clay (the paper is published in Croatian .

Alternate cap designs under RCRA regulations

International Nuclear Information System (INIS)

Manrod, W.E. III; Yager, R.E.; Craig, P.M.

1988-01-01

Low-level radioactive waste and mixed wastes have been disposed of in several sites in the vicinity of the Oak Ridge Y-12 Plant in Tennessee. Most of these materials have been placed in shallow land burial pits (SLB). Closure plans have been developed and approved by appropriate regulatory agencies for several of these sites. A variety of cap (final cover) designs for closure of these sites were investigated to determine their ability to inhibit infiltration of precipitation to the waste. The most effective designs are those that use synthetic materials as drainage layers and/or impermeable liners. The more complex, multi-layer systems perform no better than simpler covers and would complicate construction and increase costs. Despite the successful analytical results described in this paper, additional considerations must be factored into use of geosynthetic as well as natural materials

Environmental aspects of the implementation of geogrids for pavement optimisation

Science.gov (United States)

Kawalec, Jacek; Gołos, Michał; Mazurowski, Piotr

2018-05-01

Technological developments in highway construction should not only result in durable, safe and cost-effective solutions for roads and pavements but also, and perhaps above all, lead to solutions that minimise the negative impact of construction on the environment. One of the ways to ensure these requirements are met is to apply technology using geosynthetics. This paper discusses the stabilisation of aggregate with hexagonal geogrids and the benefits - from the point of view of reducing the emission of harmful gases to the atmosphere - which can be realised from this approach, compared with traditional approaches. Solutions for the improvement of weak subgrades and optimisation of the entire pavement structure are discussed, along with the presentation of sample calculations of greenhouse gas emissions, carried out with the use of specialized software related to the construction of the structures in various technologies.

Construction quality assurance report

International Nuclear Information System (INIS)

Roscha, V.

1994-01-01

This report provides a summary of the construction quality assurance (CQA) observation and test results, including: The results of the geosynthetic and soil materials conformance testing. The observation and testing results associates with the installation of the soil liners. The observation and testing results associated with the installation of the HDPE geomembrane liner systems. The observation and testing results associated with the installation of the leachate collection and removal systems. The observation and testing results associated with the installation of the working surfaces. The observation and testing results associated with in-plant manufacturing process. Summary of submittal reviews by Golder Construction Services, Inc. The submittal and certification of the piping material specifications. The observation and verification associated of the Acceptance Test Procedure results of the operational equipment functions. Summary of the ECNs which are incorporated into the project

Proceedings of GeoHalifax 2009 : the 62. Canadian geotechnical conference and 10. joint CGS/IAH-CNC groundwater conference

Energy Technology Data Exchange (ETDEWEB)

Lake, C.; Fenton, G. [Dalhousie Univ., Halifax, NS (Canada); Taylor, B. [Stantec Consulting Ltd., Surrey, BC (Canada); Ferguson, G. [Saint Francis Xavier Univ., Antigonish, NS (Canada)] (comps.) (and others)

2009-07-01

More than 500 delegates from industry, government, universities and research centres attended this conference to exchange professional knowledge on research and development that affects all sectors of geotechnical engineering, applied geology and hydrogeology. The conference also highlighted recent geoenvironmental achievements. The geotechnical sessions were entitled: soil mechanics; soil mechanics and brownfields; foundation engineering; landslide and slopes engineering; rock mechanics; risk assessment; reliability-based design; geoenvironmental issues; transportation geotechniques; marine geotechniques and geohazards; non-textbook soils and waste soils; covers and liners; instrumentation; harbour and shoreline geotechniques; geosynthetic mechanically stabilized earth (MSE) systems; cold regions and climate change; computer applications; regional hydrogeology; groundwater-surface water interaction; well hydraulics; radioactive waste management; groundwater sustainability; source water protection; mine waters; field techniques in hydrogeology; and hydrogeology of fractured rocks. The conference featured more than 230 presentations, of which 37 have been catalogued separately for inclusion in this database. refs., tabs., figs.

Back-Analyses of Landfill Instability Induced by High Water Level: Case Study of Shenzhen Landfill

Directory of Open Access Journals (Sweden)

Ren Peng

2016-01-01

Full Text Available In June 2008, the Shenzhen landfill slope failed. This case is used as an example to study the deformation characteristics and failure mode of a slope induced by high water levels. An integrated monitoring system, including water level gauges, electronic total stations, and inclinometers, was used to monitor the slope failure process. The field measurements suggest that the landfill landslide was caused by a deep slip along the weak interface of the composite liner system at the base of the landfill. The high water level is considered to be the main factor that caused this failure. To calculate the relative interface shear displacements in the geosynthetic multilayer liner system, a series of numerical direct shear tests were carried out. Based on the numerical results, the composite lining system simplified and the centrifuge modeling technique was used to quantitatively evaluate the effect of water levels on landfill instability.

Proceedings of OttawaGeo 2007 : the Diamond Jubilee 60. Canadian Geotechnical Conference and 8. Joint CGS/IAH-CNC Groundwater Conference : Breaking Ground in the Nation's Capital

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-07-01

This conference provided a forum for more than 600 delegates from industry, government universities and research centres to share their professional knowledge on research and development that affects all sectors of geotechnical engineering, applied geology and hydrogeology. Accomplishments in the geoenvironmental field were also highlighted. The geotechnical themes included buried structures; cold region engineering; computer modelling; earthquake engineering; engineering geology; foundation engineering; landfills and contaminated sites; mining geotechniques and the environment; slope stability/landslides; unsaturated soils; geosynthetics; problematic soils; rock mechanics; soil dynamics and liquefaction; and, soil-structure interactions. The hydrogeology themes included applications of geophysics to hydrogeology; aquifer case studies; hydrogeology of the Canadian Shield; hydrogeology of the Great Lakes Basin and St. Lawrence Lowlands; quantitative performance assessment of contaminant remediation; radioactive waste management; and, source water protection. The conference featured more than 320 presentations, of which 35 have been catalogued separately for inclusion in this database. refs., tabs., figs.

Back-Analyses of Landfill Instability Induced by High Water Level: Case Study of Shenzhen Landfill

Science.gov (United States)

Peng, Ren; Hou, Yujing; Zhan, Liangtong; Yao, Yangping

2016-01-01

In June 2008, the Shenzhen landfill slope failed. This case is used as an example to study the deformation characteristics and failure mode of a slope induced by high water levels. An integrated monitoring system, including water level gauges, electronic total stations, and inclinometers, was used to monitor the slope failure process. The field measurements suggest that the landfill landslide was caused by a deep slip along the weak interface of the composite liner system at the base of the landfill. The high water level is considered to be the main factor that caused this failure. To calculate the relative interface shear displacements in the geosynthetic multilayer liner system, a series of numerical direct shear tests were carried out. Based on the numerical results, the composite lining system simplified and the centrifuge modeling technique was used to quantitatively evaluate the effect of water levels on landfill instability. PMID:26771627

Fluid migration through geo-membrane seams and through the interface between geo-membrane and geo-synthetic clay liner; Contribution a l'etude des transferts de masse au niveau des joints de geomembrane et a l'interface entre geomembrane et geosynthetique bentonitique

Energy Technology Data Exchange (ETDEWEB)

Barroso, M

2005-03-15

Composite liners are used to limit the contamination migration from landfills. Their successful performance is closely related with the geo-membrane as it provides the primary barrier to diffusive and advective transport of contaminants. Critical issues on the performance of the geo-membranes are the seams between geo-membrane panels and the inevitable defects resulting, for instance, from inadequate installation activities. In landfills, where high density polyethylene geo-membranes are usually used, seams are typically made by the thermal-hot dual wedge method. A literature review on quality control of the seams showed that, in situ, fluid-tightness of seams is evaluated in qualitative terms (pass/failure criteria), despite their importance to ensure appropriate performance of the geo-membranes as barriers. In addition, a synthesis of studies on geo-membrane defects indicated that defects varying in density from 0.7 to 15.3 per hectare can be found in landfills. Defects represent preferential flow paths for leachate. Various authors have developed analytical solutions and empirical equations for predicting the flow rate through composite liners due to defects in the geo-membrane. The validity of these methods for composite liners comprising a geo-membrane over a geo-synthetic clay liner (GCL) over a compacted clay liner (CCL) has never been studied from an experimental point of view. To address the problem of fluid migration through the geo-membrane seams, an attempt is made to provide a test method, herein termed as 'gas permeation pouch test', for assessing the quality of the thermal-hot dual wedge seams. This test consists of pressurizing the air channel formed by the double seam with a gas to a specific pressure and, then, measuring the decrease in pressure over time. From the pressure decrease, both the gas permeation coefficients, in steady state conditions, and the time constant, in unsteady state conditions, can be estimated. Experiments were

Low-level radioactive mixed waste land disposal facility -- Permanent disposal

International Nuclear Information System (INIS)

Erpenbeck, E.G.; Jasen, W.G.

1993-03-01

Radioactive mixed waste (RMW) disposal at US Department of Energy (DOE) facilities is subject to the Resource Conservation and Recovery Act of 1976 (RCRA) and the Hazardous and Solid Waste Amendments of 1984 (HSWA). Westinghouse Hanford Company, in Richland, Washington, has completed the design of a radioactive mixed waste land disposal facility, which is based on the best available technology compliant with RCRA. When completed, this facility will provide permanent disposal of solid RMW, after treatment, in accordance with the Land Disposal Restrictions. The facility includes a double clay and geosynthetic liner with a leachate collection system to minimize potential leakage of radioactive or hazardous constituents from the landfill. The two clay liners will be capable of achieving a permeability of less than 1 x 10 -7 cm/s. The two clay liners, along with the two high density polyethylene (HDPE) liners and the leachate collection and removal system, provide a more than conservative, physical containment of any potential radioactive and/or hazardous contamination

Secondary containment systems for bulk oil storage facilities

International Nuclear Information System (INIS)

Carr, B.A.

1996-01-01

The United States Environmental Protection Agency has conducted site inspections at several onshore bulk oil above ground storage facilities, to ensure that owners follow the spill prevention, control and countermeasure regulations. The four violations which were most frequently cited at these facilities were: (1) lack of a spill prevention plan, (2) lack of appropriate containment equipment to prevent discharged oil from reaching a navigable water course, (3) inadequate secondary containment structures, and (4) lack of an adequate quick drainage system in the facility tank loading/unloading area. Suggestions for feasible designs which would improve the impermeability of secondary containment for above ground storage tanks (AST) included the addition of a liner, retrofitting the bottom of an AST with a second steel plate, using a geosynthetic liner on top of the original bottom, installing a leak detection system in the interstitial space between the steel plates, or installing an under-tank liner with a leak detection system during construction of a new AST. 2 refs

Application of geocomposite placed beneath ballast bed to improve ballast quality and track stability

Science.gov (United States)

Horníček, Leoš; Břešt'ovský, Petr; Jasanský, Petr

2017-09-01

The article deals with the application of a stabilization hexagonal geocomposite for the improvement of poor stability of railway tracks caused by undesirable migration of fine soil particles from the subgrade into the ballast bed. The establishment of a test railway section on a single-line track situated near Domazlice and its long-term monitoring programme are described. Evaluation is aimed especially at track geometry parameters, the load-bearing capacity of the ballast bed, elastic rail deflection during train passages and the durability of geocomposite’s physical properties. The data taken from the test section during five measurement campaigns are compared with both adjacent sections. In one of them, only the ballast bed renovation was carried out, whereas in the second one no intervention was performed at all. The usage of a pioneering geosynthetic product in combination with new trends in ballast bed restoration seems to be an innovative as well as effective solution to analogous problematic spots on railway tracks in the Czech Republic.

Proceedings of GeoSask 2005 : The 58. Canadian Geotechnical Conference and 6. Joint CGS-IAH Groundwater Specialty Conference

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

The Canadian and international geotechnical community gathered at this conference to exchange information on recent research and development concerning all sectors of geotechnical engineering, applied geology and hydrogeology. The technical sessions addressed a wide range of geotechnical engineering issues such as soil mechanics and geodynamics; geoenvironmental issues associated with contaminant transport in landfills; hydrogeology issues such as aquifer properties, hydrogeochemistry, groundwater resources, hydrogeological mapping, contaminants and remediation; geosynthetics; geotechnical modelling; rock engineering; engineering geology; mining geotechnics; buried structures; unsaturated soils and aquitards. The presentations included several geotechnical case studies that focused on broad issues such as hydraulic properties of sedimentary rock aquifers, design criteria for geotextile filters used in agricultural drainage, the long term performance of containment systems, slope stability analysis of landfills, methane emissions from landfills, shear zones in weak rocks and tailings at oil sands operations. The conference featured approximately 200 presentations, of which 17 have been catalogued separately for inclusion in this database. refs., tabs., figs.

Numerical modelling of the reinforcing effect of geosynthetic material used in a ballasted railway tracks

Czech Academy of Sciences Publication Activity Database

Jiroušek, Ondřej; Jíra, J.; Hrdlička, Ondřej; Kunecký, Jiří; Kytýř, Daniel; Vyčichl, J.; Doktor, Tomáš

2010-01-01

Roč. 224, č. 4 (2010), s. 259-267 ISSN 0954-4097 Institutional research plan: CEZ:AV0Z20710524 Keywords : railway track bed * reinforcing geogrid * finite-element modelling * settlement reduction * contact analysis * ballast material Subject RIV: JN - Civil Engineering Impact factor: 0.389, year: 2010 http://journals.pepublishing.com/content/k561040632411117/

Laboratory Evaluation of Interactions in the Degradation of a Polypropylene Geotextile in Marine Environments

Directory of Open Access Journals (Sweden)

José Ricardo Carneiro

2018-01-01

Full Text Available The long-term behaviour of geosynthetics applied in coastal engineering structures can be adversely affected by many agents. This paper studies the resistance of a nonwoven polypropylene geotextile against some degradation agents present in marine environments and evaluates the existence of interactions between them. For that purpose, the geotextile was exposed to some laboratory degradation tests: immersion tests (in seawater, deionised water, and sodium chloride 35 g·L−1, thermooxidation, and artificial weathering. The geotextile was (1 exposed separately to each degradation test and (2 exposed successively to combinations of two or three degradation tests. The damage caused by the degradation tests was evaluated by monitoring the tensile properties of the geotextile. Based on the changes occurred in tensile strength, reduction factors were determined. The reduction factors obtained directly in the multiple exposures were compared with those obtained by the traditional methodology for the combined effect of the degradation agents. The results, among other findings, showed the existence of relevant interactions between the degradation agents and showed that the reduction factors obtained by the traditional methodology were unable to represent accurately (by underestimating the degradation occurred in the geotextile.

Analytical and Numerical Evaluation of Limit States of MSE Wall Structure

Directory of Open Access Journals (Sweden)

Drusa Marián

2016-12-01

Full Text Available Simplification of the design of Mechanically Stabilized Earth wall structures (MSE wall or MSEW is now an important factor that helps us not only to save a time and costs, but also to achieve the desired results more reliably. It is quite common way in practice, that the designer of a section of motorway or railway line gives order for design to a supplier of geosynthetics materials. However, supplier company has experience and skills, but a general designer does not review the safety level of design and its efficiency, and is simply incorporating into the overall design of the construction project. Actually, large number of analytical computational methods for analysis and design of MSE walls or similar structures are known. The problem of these analytical methods is the verification of deformations and global stability of structure. The article aims to clarify two methods of calculating the internal stability of MSE wall and their comparison with FEM numerical model. Comparison of design approaches allows us to draft an effective retaining wall and tells us about the appropriateness of using a reinforcing element.

On the performance of capillary barriers as landfill cover

Science.gov (United States)

Kämpf, M.; Montenegro, H.

Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m). In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.

On the performance of capillary barriers as landfill cover

Directory of Open Access Journals (Sweden)

M. Kämpf

1997-01-01

Full Text Available Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m. In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.

Diffusion of multiwall carbon nanotubes (MWCNTs) through a high density polyethylene (HDPE) geomembrane.

Science.gov (United States)

Saheli, P T; Rowe, R K; Petersen, E J; O'Carroll, D M

2017-05-01

The new applications for carbon nanotubes (CNTs) in various fields and consequently their greater production volume have increased their potential release to the environment. Landfills are one of the major locations where carbon nanotubes are expected to be disposed and it is important to ensure that they can limit the release of CNTs. Diffusion of multiwall carbon nanotubes (MWCNTs) dispersed in an aqueous media through a high-density polyethylene (HDPE) geomembrane (as a part of the landfill barrier system) was examined. Based on the laboratory tests, the permeation coefficient was estimated to be less than 5.1×10 -15 m 2 /s. The potential performance of a HDPE geomembrane and geosynthetic clay liner (GCL) as parts of a composite liner in containing MWCNTs was modelled for six different scenarios. The results suggest that the low value of permeation coefficient of an HDPE geomembrane makes it an effective diffusive barrier for MWCNTs and by keeping the geomembrane defects to minimum during the construction (e.g., number of holes and length of wrinkles) a composite liner commonly used in municipal solid waste landfills will effectively contain MWCNTs.

Determination of membrane behaviour during transport of pollutants n clay barriers

International Nuclear Information System (INIS)

Musso, M.; Pejon, O.

2010-01-01

The study of the transport of contaminants in clay barriers had a extensive development in environmental geotechnics. The most studied transport processes are solutes by advection - dispersion and diffusion generated by hydraulic and chemical gradients respectively. Greater attention should be given to the chemical - osmotic flow and behavior membrane clay barriers, since in one case the water molecules move through the existence of a chemical gradient and on the other the means totally or partially inhibits the passage of solutes. The team developed to measure these processes was constructed based on items international literature and performance was verified using two types of materials KCl solution . One material is a bentonite geocomposite (Geosynthetic Clay Liner GCL ) similar to that used by other researchers. The other material is a soil barrier compacted clay (Compacted Clay Liner CCL) Fm. Corumbataí (Permian), belonging to the Paraná basin in the state of Sao Paulo, Brazil . The results show the proper performance of the equipment built . Osmotic pressure generation and membrane performance was verified for both samples. Further corroborated influence of the type of clay mineral in the osmotic pressure generated value and membrane behavior

Investigations of Geosynthetic Interlayer Bonding in Asphalt Layers / Badania Połaczen Miedzywarstwowych W Warstwach Asfaltowych Z Geosyntetykiem

Directory of Open Access Journals (Sweden)

Zielinski P.

2011-12-01

Full Text Available Problem zwiazania miedzywarstwowego jest jednym z powazniejszych problemów wykonawczych w budowie nawierzchni asfaltowych, zwłaszcza w sytuacji zastosowania geosyntetyków, które sa bardzo wrazliwe na błedy aplikacji. Brak zapewnienia dobrego połaczenia warstw skutkuje zmniejszeniem trwałosci całej konstrukcji nawierzchni. Problemem badawczym jest wiec okreslenie jak spadek połaczenia warstw wpływa na trwałosc zmeczeniowa konstrukcji nawierzchni. Badania takie zostały wykonane w ramach 2 grantów badawczych, natomiast niniejszy artykuł prezentuje tylko czesc dotyczaca badan połaczen miedzywarstwowych. Badania te zostały wykonane metoda scinania opracowana na Politechnice Krakowskiej, w dwóch wybranych temperaturach tj. -2°C i + 25°C. Jako czynniki determinujace sczepnosc miedzywarstwowa przebadano wpływy rodzaju geosyntetyku, rodzaju lepiszcza stosowanego do połaczenia warstw, rodzaju mieszanki mineralno-asfaltowej a takze ilosci lepiszcza stosowanej do skropienia miedzywarstwowego. Istotnosc wpływów poszczególnych czynników na parametry zwiazania miedzywarstwowego okreslono z wykorzystaniem metod statystycznych z zastosowaniem programu Statgraphics Plus v.5.1. Stwierdzono pozytywny wpływ zastosowania geosyntetyków wstepnie impregnowanych srodkiem adhezyjnym, jako lepiszcze do nasycania i przyklejania geosyntetyku najbardziej efektywny okazał sie asfalt na goraco badz emulsja modyfikowana, stosowanie emulsji niemodyfikowanych dało gorsze rezultaty. Bardzo istotny okazał sie wpływ ilosci lepiszcza stosowanego do nasycania i przyklejania geosyntetyków. Wykazano, ze dla kazdego rodzaju warstwy posredniej istnieje optymalna ilosc skropienia miedzywarstwowego, przy której wytrzymałosc na scinanie i sztywnosc scinania jest najwieksza. Zarówno zwiekszenie jak i zmniejszenie tej ilosci lepiszcza powoduje spadek parametrów zwiazania miedzywarstwowego. W aspekcie praktycznym wyniki te pokazuja koniecznosc indywidualnego doboru rodzaju i ilosci lepiszcza do skropienia miedzywarstwowego dla konkretnego rodzaju geosyntetyku oraz warstw mineralno-asfaltowych, w których bedzie ułozony.

The effect of deep excavation-induced lateral soil movements on the behavior of strip footing supported on reinforced sand

Directory of Open Access Journals (Sweden)

Mostafa El Sawwaf

2012-10-01

Full Text Available This paper presents the results of laboratory model tests on the influence of deep excavation-induced lateral soil movements on the behavior of a model strip footing adjacent to the excavation and supported on reinforced granular soil. Initially, the response of the strip footings supported on un-reinforced sand and subjected to vertical loads (which were constant during the test due to adjacent deep excavation-induced lateral soil movement were obtained. Then, the effects of the inclusion of geosynthetic reinforcement in supporting soil on the model footing behavior under the same conditions were investigated. The studied factors include the value of the sustained footing loads, the location of footing relative to the excavation, the affected depth of soil due to deep excavation, and the relative density of sand. Test results indicate that the inclusion of soil reinforcement in the supporting sand significantly decreases both vertical settlements and the tilts of the footings due to the nearby excavation. However, the improvements in the footing behavior were found to be very dependent on the location of the footing relative to excavation. Based on the test results, the variation of the footing measured vertical settlements with different parameters are presented and discussed.

Modeling Stone Columns.

Science.gov (United States)

Castro, Jorge

2017-07-11

This paper reviews the main modeling techniques for stone columns, both ordinary stone columns and geosynthetic-encased stone columns. The paper tries to encompass the more recent advances and recommendations in the topic. Regarding the geometrical model, the main options are the "unit cell", longitudinal gravel trenches in plane strain conditions, cylindrical rings of gravel in axial symmetry conditions, equivalent homogeneous soil with improved properties and three-dimensional models, either a full three-dimensional model or just a three-dimensional row or slice of columns. Some guidelines for obtaining these simplified geometrical models are provided and the particular case of groups of columns under footings is also analyzed. For the latter case, there is a column critical length that is around twice the footing width for non-encased columns in a homogeneous soft soil. In the literature, the column critical length is sometimes given as a function of the column length, which leads to some disparities in its value. Here it is shown that the column critical length mainly depends on the footing dimensions. Some other features related with column modeling are also briefly presented, such as the influence of column installation. Finally, some guidance and recommendations are provided on parameter selection for the study of stone columns.

Performance characteristics of a self-sealing/self-healing barrier

International Nuclear Information System (INIS)

McGregor, R.G.; Stegemann, J.A.

1997-01-01

Environment Canada and the Netherlands Energy Research Foundation are co-developers of a patented Self-Sealing/Self-Healing (SS/SH) Barrier system for containment of wastes which is licensed to Water Technology International Corporation. The SS/SH Barrier is intended for use as either a liner or cover for landfills, contaminated sites, secondary containment areas, etc., in the industrial, chemical, mining and municipal sectors, and also as a barrier to hydraulic flow for the transportation and construction industry. The SS/SH Barrier's most significant feature is its capability for self-repair in the event of a breach. By contrast, conventional barrier systems, such as clay, geomembrane, or geosynthetic clay liners can not be repaired without laborious excavation and reconstruction. Laboratory investigations have shown that the SS/SH Barrier concept will function with a variety of reactive materials. Self-Sealing/Self-Healing Barriers are cost competitive and consistently exhibit hydraulic conductivities ranging from 10 -9 to 10 -13 m/s, which decrease with time. These measurements meet or exceed the recommended hydraulic conductivity required by EPA for clay liners ( -9 m/s) used in landfills and hazardous waste sites. Results of mineralogical examination of the seal, diffusion testing, hydraulic conductivity measurement, and durability testing, including wet/dry, freeze/thaw cycling and leachate compatibility are also presented

Effects of Geofoam Panels on Static Behavior of Cantilever Retaining Wall

Directory of Open Access Journals (Sweden)

Navid Hasanpouri Notash

2018-01-01

Full Text Available Geofoam is one of the geosynthetic products that can be used in geotechnical applications. According to researches, expanded polystyrene (EPS geofoam placed directly against a rigid retaining wall has been proposed as a strategy to reduce static loads on the wall. This study employed a finite difference analysis using a 2-D FLAC computer program by considering yielding and nonyielding states for retaining walls to explore the effectiveness of geofoam panels in improving the static performance of cantilever retaining walls. Retaining walls at heights of 3, 6, and 9 meters and geofoam panels with densities of 15, 20, and 25 (kg/m3 at three relative thicknesses of t/H = 0.05, 0.2, and 0.4 were modelled in this numerical study. In addition, the performance of the double EPS buffer system, which involves two vertical geofoam panels, in retaining walls’ stability with four panel spacing (50, 100, 150, and 200 cm was also evaluated in this research. The results showed that use of EPS15 with density equal to 15 (kg/m3 which has the lowest density among other geofoam panels has a significant role in reduction of lateral stresses, although the performance of geofoam in nonyielding retaining walls is better than yielding retaining walls.

Introduction of Microbial Biopolymers in Soil Treatment for Future Environmentally-Friendly and Sustainable Geotechnical Engineering

Directory of Open Access Journals (Sweden)

Ilhan Chang

2016-03-01

Full Text Available Soil treatment and improvement is commonly performed in the field of geotechnical engineering. Methods and materials to achieve this such as soil stabilization and mixing with cementitious binders have been utilized in engineered soil applications since the beginning of human civilization. Demand for environment-friendly and sustainable alternatives is currently rising. Since cement, the most commonly applied and effective soil treatment material, is responsible for heavy greenhouse gas emissions, alternatives such as geosynthetics, chemical polymers, geopolymers, microbial induction, and biopolymers are being actively studied. This study provides an overall review of the recent applications of biopolymers in geotechnical engineering. Biopolymers are microbially induced polymers that are high-tensile, innocuous, and eco-friendly. Soil–biopolymer interactions and related soil strengthening mechanisms are discussed in the context of recent experimental and microscopic studies. In addition, the economic feasibility of biopolymer implementation in the field is analyzed in comparison to ordinary cement, from environmental perspectives. Findings from this study demonstrate that biopolymers have strong potential to replace cement as a soil treatment material within the context of environment-friendly construction and development. Moreover, continuing research is suggested to ensure performance in terms of practical implementation, reliability, and durability of in situ biopolymer applications for geotechnical engineering purposes.

Green technologies in natural and synthetic surfaces use for dumps reclamation

Science.gov (United States)

Klimkina, Iryna; Fedotov, Viacheslav; Heilmeier, Hermann

2016-04-01

Last 50 years coal dumps reclamation in Ukraine was based on two- or three-layer models. These models use a fertile substratum underneath a black soil (chernozem) layer 0.5 m thick (Model 1) or 0.70-1 m thick (Model 2). Model 3 has 3 layers. The deepest layer is a substrate which is phytotoxic or unfavourable for crop growth (coal-bearing substrates with a high content of pyrite, saline substrates). The second layers acts as a protective shield and consist of loess (0.5 m). The third is the layer of fertile chernozem (0.3-0.8 m). However, due to the situation of a shortage of fertile soils, a lack of nutrient elements in the waste rock, and a moisture deficit with strong rock acidification, it is considered important to develop new non-traditional reclamation methods based on the geo-synthetic materials used in conjunction with sowing lawn grasses or grass seeds inside. The geogrids and biogeotextiles made from natural materials such as hemp, flax, jute, coconut and other plant biopolymer fibers are recommended for bioremediation. The biodegradable carcass of reclamation covering materials stabilises the slopes, effectively restraints the soil particles from leaching and blowing, and prevents wash-out of the plant seeds, as well as protecting them from being eaten by animals. The research object of the presented work was the coal dumps of sulfide rocks in Western Donbass (Ukraine). These rocks are characterized by low level of the maximum hygroscopic moisture (4.3%) and moisture content not available for plant growth (5-6%). Also the rock has an average level of salinity, mainly of the sulphate type. The main goal of the study was to justify the use of some non-traditional materials such as burlap (jute cloth), agricultural fibers (light non-woven material from polypropylene fiber of spun-bond type) and a padding of polyester in the capacity of a geosynthetic substrate as a basis for the mixed grass crop that enable a reduction in the bioremediation costs (in

Cyclic settlement behavior of strip footings resting on reinforced layered sand slope

Directory of Open Access Journals (Sweden)

Mostafa A. El Sawwaf

2012-10-01

Full Text Available The paper presents a study of the behavior of model strip footings supported on a loose sandy slope and subjected to both monotonic and cyclic loads. The effects of the partial replacement of a compacted sand layer and the inclusion of geosynthetic reinforcement were investigated. Different combinations of the initial monotonic loads and the amplitude of cyclic loads were chosen to simulate structures in which loads change cyclically such as machine foundations. The affecting factors including the location of footing relative to the slope crest, the frequency of the cyclic load and the number of load cycles were studied. The cumulative cyclic settlement of the model footing supported on a loose sandy slope, un-reinforced and reinforced replaced sand deposits overlying the loose slope were obtained and compared. Test results indicate that the inclusion of soil reinforcement in the replaced sand not only significantly increases the stability of the sandy slope itself but also decreases much both the monotonic and cumulative cyclic settlements leading to an economic design of the footings. However, the efficiency of the sand–geogrid systems depends on the properties of the cyclic load and the location of the footing relative to the slope crest. Based on the test results, the variation of cumulative settlements with different parameters is presented and discussed.

Biodegradation of paper waste using Eisenia foetida by vermicomposting Technology

Science.gov (United States)

Mathivanan, Mahalakshmi; Aravind Vishnu Saravanan, G.; Baji, Aravindh; Manoj kumar, J.

2017-07-01

The paper wastes are being a big concern over past decades. The process of reuse of the paper wastes is employed by ‘eisenia foetida’ in Vermiculture. The paper waste in SASTRA is collected around 50kg and organic wastes like vegetable wastes and cow dung wastes are also collected. In the adjacent area of Nirman Vihar, SASTRA, the experimental setup is done in a Geosynthetic polymer bag. The area is divided into three segments and in each segment appropriate amount of paper waste and organic waste were added along with 25 numbers of earthworms. The setup is watered daily and monitored periodically and it is kindled for proper aeration. The soil samples were collected on 20 days, 45 days and 60 days from the day the earthworms were added. After 60 days of the experiment, the paper wastes, compost and earthworms are separated. The quantity of the wastes was compared to the initial amount and the composts are collected. The elemental analysis of the soil used as Vermi-bed is analyzed for improvement of soil nutrients. The vermiwashed water of the setup is analyzed for total protein. The number of earthworm is also compared to initial quantity. Out of all, the loss percentage of the organic waste and paper waste shows the degradation of the paper wastes.

SCIENTIFIC SUPPORT OF SURVEY, DESIGN, CONSTRUCTION AND OPERATION OF THE MOTHER OF GOD DITCH OF SERAPHIMO-DIVEEVSKY MONASTERY

Directory of Open Access Journals (Sweden)

Darchiya Valentina Ivanovna

2018-02-01

Full Text Available Subject: the article describes the structure, technologies of construction, gardening and exploitation of the Holy Trinity Seraphimo-Diveevsky Monastery - the ancient linear fortification consisting of a ditch and an earth embankment that is located directly above the ditch. Research objectives: ensure the stability of slopes, create a technique for gardening of steep slopes in difficult microclimatic conditions, ensure drainage of water. Materials and methods: the computational techniques were used to ensure stability of slopes, and experimental techniques were applied for their phyto-fixation; geosynthetics, rebar grids, varietal herbs, gooseberries and thuja were used. Results: for recreation of the unique structure, a special set of design, survey and construction works was developed, as well as works to maintain the structure during its exploitation. In particular, we have developed the method of detection of the recreated ditch based on the stratification of bulk soils by their age; the methods for fastening the slopes; lawn grass mixture formula for slopes with angles of 45° and 65°; drainage system. Conclusions: owing to the research work, for the first time this construction was completed with the required parameters, while the earlier recreation attempts failed due to erosion and landslide processes. The developed methods can be applied for recreation of other ancient defensive fortifications on the fields of great battles and for landscaping the territories with complex relief.

Removal of Historic Low-Level Radioactive Sediment from the Port Hope Harbour - 13314

Energy Technology Data Exchange (ETDEWEB)

Kolberg, Mark [Baird and Associates, 1267 Cornwall Rd., Suite 100, Oakville ON, L6J7T5 (Canada); Case, Glenn [Atomic Energy of Canada Limited, Port Hope, ON (Canada); Ferguson Jones, Andrea [MMM Group Limited, Thornhill, ON (Canada)

2013-07-01

At the Port Hope Harbour, located on the north shore of Lake Ontario, the presence of low-level radioactive sediment, resulting from a former radium and uranium refinery that operated alongside the Harbour, currently limits redevelopment and revitalization opportunities. These waste materials contain radium-226, uranium, arsenic and other contaminants. Several other on-land locations within the community of Port Hope are also affected by the low-level radioactive waste management practices of the past. The Port Hope Project is a community initiated undertaking that will result in the consolidation of an estimated 1.2 million cubic metres of the low-level radioactive waste from the various sites in Port Hope into a new engineered above ground long-term waste management facility. The remediation of the estimated 120,000 m{sup 3} of contaminated sediments from the Port Hope Harbour is one of the more challenging components of the Port Hope Project. Following a thorough review of various options, the proposed method of contaminated sediment removal is by dredging. The sediment from the dredge will then be pumped as a sediment-water slurry mixture into geo-synthetic containment tubes for dewatering. Due to the hard substrate below the contaminated sediment, the challenge has been to set performance standards in terms of low residual surface concentrations that are attainable in an operationally efficient manner. (authors)

Bentonite-amended soil special study

International Nuclear Information System (INIS)

1989-12-01

This special study was conducted to assess the viability of soil with a high percentage of bentonite added as an infiltration barrier in the cover of Uranium Mill Tailings Remedial Action (UMTRA) Project disposal cells. To achieve maximum concentration limits (MCLs) at several UMTRA Project sites, covers with a very low permeability are needed. If alternate concentration limits (ACLs) are the appropriate site groundwater compliance strategy, the US Department of Energy (DOE) is required to demonstrate, among other things, that the infiltration to the disposal cell is as low as reasonably achievable, and hence that the cover has a very low permeability. When the study discussed here was begun, the lowest permeability element available was CLAYMAX R , a manufactured liner material constructed of natural material (bentonite clay) between two geosynthetics.The strength of soil-bentonite mixes was measured to see if they could be placed on sideslopes and not pose stability problems. Also evaluated were the hydraulic conductivities of soil-bentonite mixes. If the strengths and permeabilities of soils with a high percentage of bentonite are favorable, the soils may be used as infiltration barriers in current cover designs without changing pile geometries. The scope of work for this study called for a literature review and a two-phased laboratory testing program. This report presents the results of the literature review and the first phase of the testing program

Removal of Historic Low-Level Radioactive Sediment from the Port Hope Harbour - 13314

International Nuclear Information System (INIS)

Kolberg, Mark; Case, Glenn; Ferguson Jones, Andrea

2013-01-01

At the Port Hope Harbour, located on the north shore of Lake Ontario, the presence of low-level radioactive sediment, resulting from a former radium and uranium refinery that operated alongside the Harbour, currently limits redevelopment and revitalization opportunities. These waste materials contain radium-226, uranium, arsenic and other contaminants. Several other on-land locations within the community of Port Hope are also affected by the low-level radioactive waste management practices of the past. The Port Hope Project is a community initiated undertaking that will result in the consolidation of an estimated 1.2 million cubic metres of the low-level radioactive waste from the various sites in Port Hope into a new engineered above ground long-term waste management facility. The remediation of the estimated 120,000 m 3 of contaminated sediments from the Port Hope Harbour is one of the more challenging components of the Port Hope Project. Following a thorough review of various options, the proposed method of contaminated sediment removal is by dredging. The sediment from the dredge will then be pumped as a sediment-water slurry mixture into geo-synthetic containment tubes for dewatering. Due to the hard substrate below the contaminated sediment, the challenge has been to set performance standards in terms of low residual surface concentrations that are attainable in an operationally efficient manner. (authors)

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.

Cover and liner system designs for mixed-waste disposal

International Nuclear Information System (INIS)

MacGregor, A.

1994-01-01

Land disposal of mixed waste is subject to a variety of regulations and requirements. Landfills will continue to be a part of waste management plans at virtually all facilities. New landfills are planned to serve the ongoing needs of the national laboratories and US Department of Energy (DOE) facilities, and environmental restoration wastes will ultimately need to be disposed in these landfills. This paper reviews the basic objectives of mixed-waste disposal and summarizes key constraints facing planners and designers of these facilities. Possible objectives of cover systems include infiltration reduction; maximization of evapotranspiration; use of capillary barriers or low-permeability layers (or combinations of all these); lateral drainage transmission; plant, animal, and/or human intrusion control; vapor/gas control; and wind and water erosion control. Liner system objectives will be presented, and will be compared to the US Environmental Protection Agency-US Nuclear Regulatory Commission guidance for mixed-waste landfills. The measures to accomplish each objective will be reviewed. Then, the design of several existing or planned mixed-waste facilities (DOE and commercial) will be reviewed to illustrate the application of the various functional objectives. Key issues will include design life and performance period as compared/contrasted to postclosure care periods, the use (or avoidance) of geosynthetics or clays, intermediate or interim cover systems, and soil erosion protection in contrast to vegetative enhancement. Possible monitoring approaches to cover systems and landfill installations will be summarized as well

Analysis on the Long Term Effect of Trial Test Road Constructed on Batu Pahat Soft Clay (BPSC) at Recess UTHM

Science.gov (United States)

Idrus, M. M. M.; Edayu, A. E.; Adnan, Z.; Ismail, B.

2016-07-01

The reinforcement used in soil for construction of roads on the soft clay is very important as it will determine the level of service of the road after it was built. Damage or defects on the road surface to be an indicator of the level of the road has dropped and shows the deformation of the road. For this research, an analysis has carried out on the long-term effect of trial test road constructed on Batu Pahat Soft Clay (BPSC) at RECESS UTHM. Through this research, the reinforcement using Rawell Geosynthetic Clay Liner (RGCL) was the best with the stability is 14964 N, a low flow is 2.69mm, stiffness modulus is 1766 MPa, the peak load is 739.4 N and a lower horizontal deformation which is 1.71 µm compared Woven Geotextile section and section without geotextile [1] [9]. In terms of deformation can be seen clearly from physical observations that section without geotextile suffered significant damage than others. Settlement of road can also be analyzed by a longitudinal section that plotted based on the result of leveling work. After that, settlements are more visible way on the right side of the road trial. Through lab tests conducted, it indicate that the coring samples obtained from sites of each section meets the specifications set by the Jabatan Kerja Raya (JKR) in terms of stability, flow and stiffness [1]. Through this study, a trial road built on soft soil can be used as a test site because of the uniqueness of these roads which has three different types of reinforcements.

Methane mass balance at three landfill sites: What is the efficiency of capture by gas collection systems?

International Nuclear Information System (INIS)

Spokas, K.; Bogner, J.; Chanton, J.P.; Morcet, M.; Aran, C.; Graff, C.; Golvan, Y. Moreau-Le; Hebe, I.

2006-01-01

Many developed countries have targeted landfill methane recovery among greenhouse gas mitigation strategies, since methane is the second most important greenhouse gas after carbon dioxide. Major questions remain with respect to actual methane production rates in field settings and the relative mass of methane that is recovered, emitted, oxidized by methanotrophic bacteria, laterally migrated, or temporarily stored within the landfill volume. This paper presents the results of extensive field campaigns at three landfill sites to elucidate the total methane balance and provide field measurements to quantify these pathways. We assessed the overall methane mass balance in field cells with a variety of designs, cover materials, and gas management strategies. Sites included different cell configurations, including temporary clay cover, final clay cover, geosynthetic clay liners, and geomembrane composite covers, and cells with and without gas collection systems. Methane emission rates ranged from -2.2 to >10,000 mg CH 4 m -2 d -1 . Total methane oxidation rates ranged from 4% to 50% of the methane flux through the cover at sites with positive emissions. Oxidation of atmospheric methane was occurring in vegetated soils above a geomembrane. The results of these studies were used as the basis for guidelines by the French environment agency (ADEME) for default values for percent recovery: 35% for an operating cell with an active landfill gas (LFG) recovery system, 65% for a temporary covered cell with an active LFG recovery system, 85% for a cell with clay final cover and active LFG recovery, and 90% for a cell with a geomembrane final cover and active LFG recovery

Study of long term chemo-hydro-mechanic behaviour of hydraulic barrier reinforced by polymer

International Nuclear Information System (INIS)

Razakamanantsoa, Andry Rico

2009-01-01

Passive barrier for landfill liners are designed with bentonite material as Geo-synthetic Clay Liners (GCL's) or Sand Bentonite Mixtures (SBM). This thesis is focused on the experimental study of the long term Chemo-Hydro-Mechanic behaviour of polymer treated geo-materials. Tests are performed with two powder polyelectrolyte polymers (P1, P2). Soil and one selected type of bentonite from a set of six are used. The corresponding testing fluid is composed with: synthesized leachate, CaCl_2 and NaCl. This first step of the study is to select the suitable bentonite (B) and the corresponding polymer concentration (2%) that gives the best swelling ability to the bentonite. Compatibility test of the bentonite polymer mixture with synthesized leachable is done. Tests are performed by fabricating GL's, with filter press and oedo-permeameter. Results show that hydraulic performance grows with the bentonite concentration. And the LS aggressiveness occurs immediately in a case of bentonite. The effects of polymer treatment are different: P1 increases the swelling ability of bentonite by flocculation, P2 increases the hydraulic performance of the bentonite by dispersion. The long term hydraulic performance tests with SBM are carried out with a rigid wall permeameter. Tests results show that pre-hydration delays only the fluid aggressiveness in spite of reducing the corresponding effects. The long term effect of polymer treatment reveals benefits to geo-material behaviour by increasing water retention and reducing the undesired effects of pollutant. The chemical index is proposed to forecast the geo-material degradation. (author)

Engineered covers for mud pit closures Central Nevada Test Area, Nevada

International Nuclear Information System (INIS)

Madsen, D.D.

2000-01-01

Two abandoned drilling mud pits impacted with petroleum hydrocarbons were determined to require closure action at the Central Nevada Test Area. The UC-4 Mud Pit C is approximately 0.12 hectares (0.3 acres) and 1.2 meters (4 feet) in depth. The UC-1 Central Mud Pit (CMP) is approximately 1.54 hectares (3.8 acres) and 2.4 meters (8 feet) in depth. Both mud pits contain bentonite drilling muds with a thin dry crust, low shear strength, low permeability, and high moisture content. The following closure methodologies were evaluated: stabilization by mixing/injection with soil, fly ash, and lime; excavation and disposal; on-site drying; thermal destruction; wick drains; administrative closure (postings and land-use restrictions); and engineered covers. Based upon regulatory closure criteria, implementation, and cost considerations, the selected remedial alternative was the construction of an engineered cover. A multilayered cover with a geo-grid and geo-synthetic clay liner (GCL) was designed and constructed over the UC-4 Mud Pit C to evaluate the constructability and applicability of the design for the CMP cover. The geo-grid provided structural strength for equipment and material loads during cover construction, and the GCL was used as a moisture infiltration barrier. The design was determined to be constructable and applicable. To reduce project costs for the CMP cover, a vegetative cover was designed with drainage toward the center of the cover rather than the perimeter. The vegetative cover with the internal drainage design resulted in a fill volume reduction of approximately 63 percent compared to the multilayered cover design with a GCL

Laboratory testing of closure cap repair techniques

International Nuclear Information System (INIS)

Persoff, P.; Moridis, G.; Tuck, D.M.

1996-10-01

Landfill design requires a low permeability closure cap as well as a low permeability liner. The Savannah River Site, in South Carolina, has approximately 85 acres of mixed waste landfills covered with compacted kaolin clay. Maintaining low permeability of the clay cap requires both that the permeability of the compacted clay itself remain low and that the integrity of the barrier be maintained. Barrier breaches typically result from penetration by roots or animals, and especially cracks caused by uneven settling or desiccation. In this study, clay layers, 0.81 m in diameter and 7.6 cm thick, were compacted in 7 lysimeters to simulate closure caps. The hydraulic conductivity of each layer was measured, and the compacted clay layers (CCL's) were cracked by drying. Then various repair techniques were applied and the effectiveness of each repair was assessed by remeasuring the hydraulic conductivity. Finally the repaired CCL was again dried and measured to determine how the repair responded to the conditions that caused the original failure. For a full report of this investigation see Persoff et al. Six repair techniques have been tested, four of which involve the use of injectable barrier liquids colloidal silica (CS) and polysiloxane (PSX) described below: (I) covering the crack with a bentonite geosynthetic clay liner (GCL), (ii) recompaction of new kaolinite at STD+3 moisture content joined to existing kaolinite that had dried and shrunk, (iii) direct injection of colloidal silica to a crack, (iv) injection of colloidal silica (CS) to wells in an overlying sand layer, (v) direct injection of polysiloxane to a crack, and (vi), injection of polysiloxane (PSX) to wells in an overlying soil layer

Inferred performance of surface hydraulic barriers from landfill operational data

International Nuclear Information System (INIS)

Gross, B.A.; Bonaparte, R.; Othman, M.A.

1997-01-01

There are few published data on the field performance of surface hydraulic barriers (SHBs) used in waste containment or remediation applications. In contrast, operational data for liner systems used beneath landfills are widely available. These data are frequently collected and reported as a facility permit condition. This paper uses leachate collection system (LCS) and leak detection system (LDS) liquid flow rate and chemical quality data collected from modem landfill double-liner systems to infer the likely hydraulic performance of SHBs. Operational data for over 200 waste management unit liner systems are currently being collected and evaluated by the authors as part of an ongoing research investigation for the United States Environmental Protection Agency (USEPA). The top liner of the double-liner system for the units is either a geomembrane (GMB) alone, geomembrane overlying a geosynthetic clay liner (GMB/GCL), or geomembrane overlying a compacted clay liner (GMB/CCL). In this paper, select data from the USEPA study are used to: (i) infer the likely efficiencies of SHBs incorporating GMBs and overlain by drainage layers; and (ii) evaluate the effectiveness of SHBs in reducing water infiltration into, and drainage from, the underlying waste (i.e., source control). SHB efficiencies are inferred from calculated landfill liner efficiencies and then used to estimate average water percolation rates through SHBs as a function of site average annual rainfall. The effectiveness of SHBs for source control is investigated by comparing LCS liquid flow rates for open and closed landfill cells. The LCS flow rates for closed cells are also compared to the estimated average water percolation rates through SHBs presented in the paper

An analytical model for solute transport through a GCL-based two-layered liner considering biodegradation

Energy Technology Data Exchange (ETDEWEB)

Guan, C. [Institute of Hydrology and Water Resources Engineering, Zhejiang University, Hangzhou 310058 (China); Xie, H.J., E-mail: xiehaijian@zju.edu.cn [Institute of Hydrology and Water Resources Engineering, Zhejiang University, Hangzhou 310058 (China); MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058 (China); Wang, Y.Z.; Chen, Y.M.; Jiang, Y.S.; Tang, X.W. [MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058 (China)

2014-01-01

An analytical model for solute advection and dispersion in a two-layered liner consisting of a geosynthetic clay liner (GCL) and a soil liner (SL) considering the effect of biodegradation was proposed. The analytical solution was derived by Laplace transformation and was validated over a range of parameters using the finite-layer method based software Pollute v7.0. Results show that if the half-life of the solute in GCL is larger than 1 year, the degradation in GCL can be neglected for solute transport in GCL/SL. When the half-life of GCL is less than 1 year, neglecting the effect of degradation in GCL on solute migration will result in a large difference of relative base concentration of GCL/SL (e.g., 32% for the case with half-life of 0.01 year). The 100-year solute base concentration can be reduced by a factor of 2.2 when the hydraulic conductivity of the SL was reduced by an order of magnitude. The 100-year base concentration was reduced by a factor of 155 when the half life of the contaminant in the SL was reduced by an order of magnitude. The effect of degradation is more important in approving the groundwater protection level than the hydraulic conductivity. The analytical solution can be used for experimental data fitting, verification of complicated numerical models and preliminary design of landfill liner systems. - Highlights: •Degradation of contaminants was considered in modeling solute transport in GCL/SL. •Analytical solutions were derived for assessment of GCL/SL with degradation. •Degradation in GCL can be ignored as half-life is larger than 1 year. •Base concentration is more sensitive to half-life of SL than to permeability of SL.

Definitive design report: Design report project W-025, Radioactive Mixed Waste (RMW) Land Disposal Facility NON-DRAG-OFF. Revision 1, Volume 1 and 2

International Nuclear Information System (INIS)

Roscha, V.

1994-01-01

The purpose of this report is to describe the definitive design of the Radioactive Mixed Waste (RMW) Non-Drag-Off disposal facility, Project W-025. This report presents a n of the major landfill design features and a discussion of how each of the criteria is addressed in the design. The appendices include laboratory test results, design drawings, and individual analyses that were conducted in support of the design. Revision 1 of this document incorporates design changes resulting from an increase in the required operating life of the W-025 landfill from 2 to 20 years. The rationale for these design changes is described in Golder Associates Inc. 1991a. These changes include (1) adding a 1.5-foot-thick layer of compacted admix directory-under the primary FML on the floor of the landfill to mitigate the effects of possible stress cracking in the primary flexible membrane liner (FML), and (2) increasing the operations layer thickness from two to three feet over the entire landfill area, to provide additional protection for the secondary admix layer against mechanical damage and the effects of freezing and desiccation. The design of the W-025 Landfill has also been modified in response to the results of the EPA Method 9090 chemical compatibility testing program (Golder Associates Inc. 1991b and 1991c), which was completed after the original design was prepared. This program consisted of testing geosynthetic materials and soil/bentonite admix with synthetic leachate having the composition expected during the life of the W-025 Landfill., The results of this program indicated that the polyester geotextile originally specified for the landfill might be susceptible to deterioration. On this basis, polypropylene geotextiles were substituted as a more chemically-resistant alternative. In addition, the percentage of bentonite in the admix was increased to provide sufficiently low permeability to the expected leachate

An analytical model for solute transport through a GCL-based two-layered liner considering biodegradation

International Nuclear Information System (INIS)

Guan, C.; Xie, H.J.; Wang, Y.Z.; Chen, Y.M.; Jiang, Y.S.; Tang, X.W.

2014-01-01

An analytical model for solute advection and dispersion in a two-layered liner consisting of a geosynthetic clay liner (GCL) and a soil liner (SL) considering the effect of biodegradation was proposed. The analytical solution was derived by Laplace transformation and was validated over a range of parameters using the finite-layer method based software Pollute v7.0. Results show that if the half-life of the solute in GCL is larger than 1 year, the degradation in GCL can be neglected for solute transport in GCL/SL. When the half-life of GCL is less than 1 year, neglecting the effect of degradation in GCL on solute migration will result in a large difference of relative base concentration of GCL/SL (e.g., 32% for the case with half-life of 0.01 year). The 100-year solute base concentration can be reduced by a factor of 2.2 when the hydraulic conductivity of the SL was reduced by an order of magnitude. The 100-year base concentration was reduced by a factor of 155 when the half life of the contaminant in the SL was reduced by an order of magnitude. The effect of degradation is more important in approving the groundwater protection level than the hydraulic conductivity. The analytical solution can be used for experimental data fitting, verification of complicated numerical models and preliminary design of landfill liner systems. - Highlights: •Degradation of contaminants was considered in modeling solute transport in GCL/SL. •Analytical solutions were derived for assessment of GCL/SL with degradation. •Degradation in GCL can be ignored as half-life is larger than 1 year. •Base concentration is more sensitive to half-life of SL than to permeability of SL

Experimental Studies on Geocells and Mat Systems for Stabilization of Unpaved Shoulders and Temporary Roads

Science.gov (United States)

Guo, Jun

Geosynthetics have been used to improve the performance of geomaterials, especially when weak soil exists in roadway applications. In this study, two types of geosynthetic materials, geocell and a mat system, were studied for their applications for unpaved roads and shoulders. The study of geocell was focused on its application for unpaved shoulders. The ability of geocell to improve different geomaterials over intermediate strength subgrade and its possible effect on vegetation were investigated. The study of the mat system was focused on investigating the performance of the mat system over soft and intermediate subgrade with different strengths under cyclic loading to simulate temporary roadway conditions. In the study of geocell for the application for unpaved shoulders, six large scale plate loading tests were conducted on a single type of geocell on target 5% CBR subgrade to investigate the benefits of geocell reinforcement on different base course and topsoil combinations. Different base course and topsoil combinations were investigated including: 200-mm thick unreinforced aggregate, 200-mm thick soil-aggregate mixture (50% aggregate and 50% top soil) with and without geocell reinforcement, 200-mm thick geocell-reinforced topsoil, 50-mm thick aggregate over 150-mm soil-aggregate mixture (50% aggregate and 50% top soil), and 50-mm thick top soil over 150-mm thick geocell-reinforced soil-aggregate mixture (50% aggregate and 50% top soil). Earth pressure cells were install at the interface between subgrade and base course to monitor the load distribution. The cyclic plate loading tests showed that geocell effectively reduced the permanent deformation and the geocell-reinforced soil-aggregate mixture slightly outperformed the unreinforced aggregate at the same thickness. The plate loading tests also suggested the topsoil cover resulted in large permanent deformations. A one-year long outdoor field vegetation test was conducted on base courses with different

Corrective Action Plan for Corrective Action Unit 417: Central Nevada Test Area Surface, Nevada

Energy Technology Data Exchange (ETDEWEB)

K. Campbell

2000-04-01

This Corrective Action Plan provides methods for implementing the approved corrective action alternative as provided in the Corrective Action Decision Document for the Central Nevada Test Area (CNTA), Corrective Action Unit (CAU) 417 (DOE/NV, 1999). The CNTA is located in the Hot Creek Valley in Nye County, Nevada, approximately 137 kilometers (85 miles) northeast of Tonopah, Nevada. The CNTA consists of three separate land withdrawal areas commonly referred to as UC-1, UC-3, and UC-4, all of which are accessible to the public. CAU 417 consists of 34 Corrective Action Sites (CASs). Results of the investigation activities completed in 1998 are presented in Appendix D of the Corrective Action Decision Document (DOE/NV, 1999). According to the results, the only Constituent of Concern at the CNTA is total petroleum hydrocarbons (TPH). Of the 34 CASs, corrective action was proposed for 16 sites in 13 CASs. In fiscal year 1999, a Phase I Work Plan was prepared for the construction of a cover on the UC-4 Mud Pit C to gather information on cover constructibility and to perform site management activities. With Nevada Division of Environmental Protection concurrence, the Phase I field activities began in August 1999. A multi-layered cover using a Geosynthetic Clay Liner as an infiltration barrier was constructed over the UC-4 Mud Pit. Some TPH impacted material was relocated, concrete monuments were installed at nine sites, signs warning of site conditions were posted at seven sites, and subsidence markers were installed on the UC-4 Mud Pit C cover. Results from the field activities indicated that the UC-4 Mud Pit C cover design was constructable and could be used at the UC-1 Central Mud Pit (CMP). However, because of the size of the UC-1 CMP this design would be extremely costly. An alternative cover design, a vegetated cover, is proposed for the UC-1 CMP.

Simultaneous sorption of As, B, Cr, Mo and Se from coal fly ash leachates by Al(sup3+)-pillared bentonite clay: implication for the construction of activated geo-synthetic clay liner

CSIR Research Space (South Africa)

Masindi, Vhahangwele

2017-03-01

Full Text Available successfully removed oxyanion species from generated coal FA leachates. This study shows that Al(sup3+)-modified bentonite clay is an effective adsorbent for oxyanion species in coal FA leachates and could be applied as a reactive barrier in coal FA retention...

A hybrid method for quasi-three-dimensional slope stability analysis in a municipal solid waste landfill.

Science.gov (United States)

Yu, L; Batlle, F

2011-12-01

Limited space for accommodating the ever increasing mounds of municipal solid waste (MSW) demands the capacity of MSW landfill be maximized by building landfills to greater heights with steeper slopes. This situation has raised concerns regarding the stability of high MSW landfills. A hybrid method for quasi-three-dimensional slope stability analysis based on the finite element stress analysis was applied in a case study at a MSW landfill in north-east Spain. Potential slides can be assumed to be located within the waste mass due to the lack of weak foundation soils and geosynthetic membranes at the landfill base. The only triggering factor of deep-seated slope failure is the higher leachate level and the relatively high and steep slope in the front. The valley-shaped geometry and layered construction procedure at the site make three-dimensional slope stability analyses necessary for this landfill. In the finite element stress analysis, variations of leachate level during construction and continuous settlement of the landfill were taken into account. The "equivalent" three-dimensional factor of safety (FoS) was computed from the individual result of the two-dimensional analysis for a series of evenly spaced cross sections within the potential sliding body. Results indicate that the hybrid method for quasi-three-dimensional slope stability analysis adopted in this paper is capable of locating roughly the spatial position of the potential sliding mass. This easy to manipulate method can serve as an engineering tool in the preliminary estimate of the FoS as well as the approximate position and extent of the potential sliding mass. The result that FoS obtained from three-dimensional analysis increases as much as 50% compared to that from two-dimensional analysis implies the significance of the three-dimensional effect for this study-case. Influences of shear parameters, time elapse after landfill closure, leachate level as well as unit weight of waste on FoS were also

Design of the Long-term Waste Management Facility for Historic LLRW Port Hope Project - 13322

International Nuclear Information System (INIS)

Campbell, Don; Barton, David; Case, Glenn

2013-01-01

The Municipality of Port Hope is located on the northern shores of Lake Ontario approximately 100 km east of Toronto, Ontario, Canada. Starting in the 1930's, radium and later uranium processing by Eldorado Gold Mines Limited (subsequently Eldorado Nuclear Limited) (Eldorado) at their refinery in Port Hope resulted in the generation of process residues and wastes that were disposed of indiscriminately throughout the Municipality until about the mid-1950's. These process residues contained radium (Ra- 226), uranium, arsenic and other contaminants. Between 1944 and 1988, Eldorado was a Federal Crown Corporation, and as such, the Canadian Federal Government has assumed responsibility for the clean-up and long-term management of the historic waste produced by Eldorado during this period. The Port Hope Project involves the construction and development of a new long-term waste management facility (LTWMF), and the remediation and transfer of the historic wastes located within the Municipality of Port Hope to the new LTWMF. The new LTWMF will consist of an engineered above-ground containment mound designed to contain and isolate the wastes from the surrounding environment for the next several hundred years. The design of the engineered containment mound consists of a primary and secondary composite base liner system and composite final cover system, made up of both natural materials (e.g., compacted clay, granular materials) and synthetic materials (e.g., geo-synthetic clay liner, geo-membrane, geo-textiles). The engineered containment mound will cover an area of approximately 13 hectares and will contain the estimated 1.2 million cubic metres of waste that will be generated from the remedial activities within Port Hope. The LTWMF will also include infrastructure and support facilities such as access roads, administrative offices, laboratory, equipment and personnel decontamination facilities, waste water treatment plant and other ancillary facilities. Preliminary

Design of the Long-term Waste Management Facility for Historic LLRW Port Hope Project - 13322

Energy Technology Data Exchange (ETDEWEB)

Campbell, Don; Barton, David [Conestoga-Rovers and Associates, 651 Colby Drive, Waterloo, Ontario N2V 1C2 (Canada); Case, Glenn [Atomic Energy of Canada Limited, 115 Toronto Road, Port Hope, Ontario L1A 3S4 (Canada)

2013-07-01

The Municipality of Port Hope is located on the northern shores of Lake Ontario approximately 100 km east of Toronto, Ontario, Canada. Starting in the 1930's, radium and later uranium processing by Eldorado Gold Mines Limited (subsequently Eldorado Nuclear Limited) (Eldorado) at their refinery in Port Hope resulted in the generation of process residues and wastes that were disposed of indiscriminately throughout the Municipality until about the mid-1950's. These process residues contained radium (Ra- 226), uranium, arsenic and other contaminants. Between 1944 and 1988, Eldorado was a Federal Crown Corporation, and as such, the Canadian Federal Government has assumed responsibility for the clean-up and long-term management of the historic waste produced by Eldorado during this period. The Port Hope Project involves the construction and development of a new long-term waste management facility (LTWMF), and the remediation and transfer of the historic wastes located within the Municipality of Port Hope to the new LTWMF. The new LTWMF will consist of an engineered above-ground containment mound designed to contain and isolate the wastes from the surrounding environment for the next several hundred years. The design of the engineered containment mound consists of a primary and secondary composite base liner system and composite final cover system, made up of both natural materials (e.g., compacted clay, granular materials) and synthetic materials (e.g., geo-synthetic clay liner, geo-membrane, geo-textiles). The engineered containment mound will cover an area of approximately 13 hectares and will contain the estimated 1.2 million cubic metres of waste that will be generated from the remedial activities within Port Hope. The LTWMF will also include infrastructure and support facilities such as access roads, administrative offices, laboratory, equipment and personnel decontamination facilities, waste water treatment plant and other ancillary facilities

A hybrid method for quasi-three-dimensional slope stability analysis in a municipal solid waste landfill

International Nuclear Information System (INIS)

Yu, L.; Batlle, F.

2011-01-01

Highlights: → A quasi-three-dimensional slope stability analysis method was proposed. → The proposed method is a good engineering tool for 3D slope stability analysis. → Factor of safety from 3D analysis is higher than from 2D analysis. → 3D analysis results are more sensitive to cohesion than 2D analysis. - Abstract: Limited space for accommodating the ever increasing mounds of municipal solid waste (MSW) demands the capacity of MSW landfill be maximized by building landfills to greater heights with steeper slopes. This situation has raised concerns regarding the stability of high MSW landfills. A hybrid method for quasi-three-dimensional slope stability analysis based on the finite element stress analysis was applied in a case study at a MSW landfill in north-east Spain. Potential slides can be assumed to be located within the waste mass due to the lack of weak foundation soils and geosynthetic membranes at the landfill base. The only triggering factor of deep-seated slope failure is the higher leachate level and the relatively high and steep slope in the front. The valley-shaped geometry and layered construction procedure at the site make three-dimensional slope stability analyses necessary for this landfill. In the finite element stress analysis, variations of leachate level during construction and continuous settlement of the landfill were taken into account. The 'equivalent' three-dimensional factor of safety (FoS) was computed from the individual result of the two-dimensional analysis for a series of evenly spaced cross sections within the potential sliding body. Results indicate that the hybrid method for quasi-three-dimensional slope stability analysis adopted in this paper is capable of locating roughly the spatial position of the potential sliding mass. This easy to manipulate method can serve as an engineering tool in the preliminary estimate of the FoS as well as the approximate position and extent of the potential sliding mass. The result that

Comparison of slope stability in two Brazilian municipal landfills.

Science.gov (United States)

Gharabaghi, B; Singh, M K; Inkratas, C; Fleming, I R; McBean, E

2008-01-01

The implementation of landfill gas to energy (LFGTE) projects has greatly assisted in reducing the greenhouse gases and air pollutants, leading to an improved local air quality and reduced health risks. The majority of cities in developing countries still dispose of their municipal waste in uncontrolled 'open dumps.' Municipal solid waste landfill construction practices and operating procedures in these countries pose a challenge to implementation of LFGTE projects because of concern about damage to the gas collection infrastructure (horizontal headers and vertical wells) caused by minor, relatively shallow slumps and slides within the waste mass. While major slope failures can and have occurred, such failures in most cases have been shown to involve contributory factors or triggers such as high pore pressures, weak foundation soil or failure along weak geosynthetic interfaces. Many researchers who have studied waste mechanics propose that the shear strength of municipal waste is sufficient such that major deep-seated catastrophic failures under most circumstances require such contributory factors. Obviously, evaluation of such potential major failures requires expert analysis by geotechnical specialists with detailed site-specific information regarding foundation soils, interface shearing resistances and pore pressures both within the waste and in clayey barrier layers or foundation soils. The objective of this paper is to evaluate the potential use of very simple stability analyses which can be used to study the potential for slumps and slides within the waste mass and which may represent a significant constraint on construction and development of the landfill, on reclamation and closure and on the feasibility of a LFGTE project. The stability analyses rely on site-specific but simple estimates of the unit weight of waste and the pore pressure conditions and use "generic" published shear strength envelopes for municipal waste. Application of the slope stability

Properties of the bentonite from Lieskovec deposit and their possible environmental applications

International Nuclear Information System (INIS)

Andrejkovicova, S.

2008-01-01

The community increasingly focuses on broader uses of raw materials, occurring in relatively sufficient amounts. Among them, bentonite play very important role in the environmental applications. Results presented herein are related to the yet comprehensively unexplored Fe-rich bentonite from Lieskovec deposit, Central Slovakia. The objective of this study was complex investigation of Lieskovec bentonite deposit. This bentonite was developed from andesitic pyroclastics; the dominant mineral in all the samples is iron-rich montmorillonite, covering 29 to 56 mass % in the samples. The accessory minerals include kaolinite (5-17 mass %), quartz (3-28 mass %), muscovite/illite (3-16 mass %), volcanic glass (6-14 mass %), orthoclase (1-12 mass %), opal (1-8 mass %) and cristobalite (1-3 mass %). Structural Fe(III) is mainly in phyllosilicates accounting for 70 % to 90 % of the total Fe in the unfractionated samples; less than 5 % is Fe(II). The remainder of the Fe is present in oxide and/or oxyhydroxide phases dominated by poorly ordered goethite and hematite with possibly some maghemite. Basic properties of bentonites result from the structure of the smectites. Size fractionation did not lead to pure smectite. Kaolinite and mica were not successfully removed. Quartz and feldspars were dismantled effectively. Non-clay minerals contribution decreased. Smectite content increased after separation up to 75 mass %. Low cation exchange capacities between 35 and 61 meq/100 g are caused also by low magnesium content in the octahedral sheets of montmorillonite, suggesting lower isomorphic Mg for Al substitution in the octahedral sheets of smectite and thus its lower octahedral charge. The main factor influencing CECs is smectite content affecting dominantly also the geotechnical properties. Geotechnical properties of Lieskovec bentonite, such as liquid limit in range 64-80 % and water adsorption by Enslin test 123-265 % were insufficient for utilization in geo-synthetic clay

Diffusion, sorption, and retardation processes of anions in bentonite and organo-bentonites for multibarrier systems

Science.gov (United States)

Schampera, Birgit; Dultz, Stefan

2013-04-01

experiments with NO3- will support the understanding of sorption behavior of the anions. All hydrophilic samples have a higher retardation capacity, indicated by diffusion coefficients of 2.44 x 10-11 m/s2 for original bentonite and ˜2.1 x 10-11m/s2 for hydrophilic organo-clays. For hydrophobic organo-clays the H2O diffusion can be higher and is increased at high bulk density (1-1.5 g/m3) up to 2.76 x 10-10m2/s. Experiments with NO3- at bulk density of 1.5 g/m3 reveal that the apparent diffusion coefficients of nitrate are with results up to 5.61 x 1012 m2/s distinctively lower than free diffusion of nitrate in pure water (6.46 x 1010 m2/s at experimental conditions) and nitrate diffusion in natural bentonite (2.63 x 1011 m2/s). The measurements allow the interpretation of the different sorption mechanisms, retardation capacity and diffusion behavior of the analyzed clays at different anion concentrations. Ongoing molecular dynamic simulations will contribute understanding of diffusion processes in organo-clays including the conditions at the interface of the clay minerals and in solution. References: [1] Shackelford, C.D., Moore S.M. (2013) Fickian diffusion of radionuclides for engineered containment barriers: Diffusion coefficients, porosities, and complicating issues. Engineering Geology, 152, 133-147. [2] Rytwo, G., Nir, S., Shuali, U. (2012) Clay and water treatment. Applied Clay Science, 67-68, 117-118. [3] Lorenzetti, R.L., Bartelt-Hunt, S.L., Burns, S.E., Smith, J.A. (2005) Hydraulic conductivities and effective diffusion coefficients of geosynthetic clay liners with organobentonite amendments. Geotextiles and Geomembranes, 23, 385-400. [4] Schampera, B., Dultz, S. (2011) H2O self-diffusion in compacted clays as influenced by surface charge and wettability - obstruction effects of bound H2O layers. Clay and Clay Minerals,59, 42-57.

POST CLOSURE INSPECTION AND MONITORING REPORT FOR CORRECTIVE ACTION UNIT 417: CENTRAL NEVADA TEST AREA - SURFACE, HOT CREEK VALLEY, NEVADA; FOR CALENDAR YEAR 2005

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-04-01

bentonite during the first quarter of 2006 and monitored during subsequent inspections. The cover vegetation was healthy and well established. No issues were identified with the CMP fence, gate, or subsidence monuments. No issues were identified with the warning signs and monuments at the other two UC-1 locations. The inspections at UC-3 indicated that the sites are in excellent condition. All monuments and signs showed no displacement, damage, or removal. A small erosion gully from spring rain runoff was observed during the June inspection, but it did not grow to an actionable level during 2005. No other issues or concerns were identified. Inspections performed at UC-4 Mud Pit C cover revealed that erosion rills were formed during March and September exposing the geosynthetic clay liner. Both erosion rills were repaired within 90 days of reporting. Sparse vegetation is present on the cover. The overall condition of the monuments, fence, and gate are in good condition. No issues were identified with the warning signs and monuments at the other four UC-4 locations. Subsidence surveys were conducted at UC-1 CMP and UC-4 Mud Pit C in March and September of 2005. The results of the subsidence surveys indicate that the covers are performing as expected, and no unusual subsidence was observed. The June vegetation survey of the UC-1 CMP cover and adjacent areas indicated that the revegetation has been very successful. The vegetation should continue to be monitored to document any changes in the plant community and identify conditions that could potentially require remedial action in order to maintain a viable vegetative cover on the site. Vegetation surveys should be conducted only as required. Precipitation during 2005 was above average, with an annual rainfall total of 21.79 centimeters (8.58 inches). Soil moisture content data show that the UC-1 CMP cover is performing as designed, with evapotranspiration effectively removing water from the cover. It is recommended to continue