Dynamic interaction between the soil and an anchored sheet pile during seismic excitation
Degrande, G.; Praet, E.; van Zegbroeck, B.; van Marcke, P.
2002-05-01
A subdomain approach for dynamic soil-structure interaction is proposed for the linear elastic seismic analysis of an anchored sheet pile, retaining a horizontally layered soil on rigid bedrock. A hybrid solution technique is used, employing a finite element formulation for the generalized sheet pile, a thin layer formulation for the soil and a direct stiffness formulation for the tieback; the displacement vectors of the sheet pile and the soil are decomposed, using the eigenmodes of the sheet pile and the propagating or decaying modes in the soil. The discretization can be limited to the interface(s), where pointwise continuity of the displacements is enforced, whereas a weak variational formulation is used for the stress equilibrium. The solution technique is illustrated by means of a numerical example, where the harmonic response of a flexible anchored sheet pile is considered and compared to the case where no tieback is present.
Increasing pull-out capacity of granular pile anchors in expansive soils using base geosynthetics
Energy Technology Data Exchange (ETDEWEB)
Phani Kumar, B.R.; Ramachandra Rao, N. [JNTU College of Engineering, Kakinada (India)
2000-08-04
Expansive soils react to changes in moisture regimes by swelling and shrinking. As a result civil engineering structures such as foundations, retaining walls, pavements, canal beds and linings built on them can suffer damage. Granular pile anchors are new and effective ways to resist the uplift pressure exerted on the foundation by swelling expansive soil. The foundation of the anchors is cemented at the bottom of a granular pile to a plate using a steel rod which renders the granular pile tension-resistant and allows it to resist the uplift force. This resistance depends mostly on the shear parameters of the pile-soil interface and the lateral swelling pressure of the soil. Placing a base geosynthetic above the anchor can further increase the resistance to uplift. The increase in resistance results from the friction between the geosynthetic and the confining media when the uplift load acts on the pile and the geosynthetic moves along with the pile. The effects of these parameters on pull-out load, rate of heave, and relative ground movement near the pile surface were discussed. 11 refs., 3 tabs., 14 figs.
Prediction of the initial normal stress in piles and anchors constructed using expansive cements
Haberfield, C. M.
2000-03-01
Uses for expansive cements and additives have extended well beyond off-setting the shrinkage characteristics of grout and concrete to include enhancement of rock anchor and pile performance, providing an alternative form of connection for tubular members in off-shore structures and as an excavation tool in open-pit mines. In each case, the design rules governing the quantity of expansive additive to be used are based on guesswork or empiricism. This paper presents analytical solutions for estimating the degree of expansion and the level of normal stress developed for a range of different boundary conditions and expansive additive contents. The expansion process is modelled as a thermal expansion and is governed by one parameter that depends on the type of expansive additive and its dosage. Simple laboratory procedures for determining this property are outlined. Predictions from the analytical solutions are compared with laboratory experiments.
Physical and numerical modelling of earth pressure on anchored sheet pile walls in sand
DEFF Research Database (Denmark)
Krogsbøll, Anette Susanne; Fuglsang, Leif D
The influence of wall flexibility on earth pressure, bending moments and failure modes is studied. Numerical models are compared to results from model tests carried out in a geotechnical centrifuge. The back-fill is dry sand and failure is introduced by allowing the wall to rotate around the anchor......-model showed the right behaviour in pre-failure as well as failure for both flexible and stiff walls, whereas the MC-model showed some shortcomings when stiff walls were modelled....
地震动对锚索桩的响应特性研究%Dynamic Response Characteristics of Anchor Cable Piles under Ground Motion
Institute of Scientific and Technical Information of China (English)
曲宏略; 胡焕国; 张建经; 朱大鹏
2015-01-01
汶川地震震害调查表明使用预应力锚索的桩板墙变形协调性好，抗震性能高，但目前在预应力锚索桩板墙的抗震设计理论研究方面仍比较落后。鉴于此，利用 FLAC3D 对预应力锚索桩板墙的地震响应特征进行研究，包括桩身土压力分布、桩身变位及锚索内锚段应力的动力响应特性等，并通过改变地震动参数进行多种工况的分析，系统研究地震动参数对桩-土-锚动力耦合相互作用规律的影响。研究成果可加强对预应力锚索桩板墙抗震表现的认识，也为深化抗震机理研究提供可靠的依据。%Prestressed anchor sheet pile wall is a light-weight retaining structure.As a new style of retaining structure,the stressed form of a prestressed anchor sheet pile is similar to a beam-style structure.This is deemed to be more reasonable than the stressed form of a cantilever that is usu-ally used for stabilizing piles.In addition,because of advanced deformation compatibility and bet-ter seismic performance,the prestressed anchor sheet pile is widely used in landslide treatment. An investigation of seismic hazards in the Wenchuan earthquake suggests that a stabilizing pile has many advantages in terms of landslide treatment.Because this structure plays an important role in landslide treatment,many researchers have performed analysis on static design and loading characteristics;however,there is limited research on the seismic design theory of prestressed an-chor sheet pile walls.The FLAC3D model was used to study the seismic response of this struc-ture,including the distribution of seismic earth pressure along the pile,deflection of the pile,and dynamic characteristics of cable stress in the anchor.In addition,the analyses of multiple cases were completed using various parameters of ground motion;thus,the influence of the parameters on the dynamic interaction law of pile-soil-anchor was systematically derived.Through FLAC3D and a
Discussion about pile-anchor retaining structure design in foundation pit%基坑桩锚支护结构设计问题探讨
Institute of Scientific and Technical Information of China (English)
李鹏; 李坤生; 张昊坤
2012-01-01
As an important form,pile-anchor retaining structure is widely used in foundation pit,but some problems still exist in design schemes that will cause hidden danger and unnecessary waste because structure calculation and constructional measures are unreasonable.Through the discussion about some easily confused problems in question such as pile in row,anchor(cable),top beam,middle beam,this article obtains some design work experience for readers' reference.%桩锚支护结构作为基坑支护的重要形式应用较广,但不少设计方案中涉及结构计算与构造措施的内容不甚恰当,造成设计安全隐患或不必要的浪费.通过对桩锚支护结构中排桩、锚杆（索）、冠梁、腰梁等构件受力、变形计算及部分易混淆问题的探讨,得出部分设计经验供参考.
Institute of Scientific and Technical Information of China (English)
王志远
2014-01-01
According to the engineering projects with narrow construction site,proposed buildings near highway or other buildings,this paper compared and analyzed the used pre-stressed anchor cable retaining pile support and un-support slope excavation in deep foundation pit construc-tion,and briefly introduced the construction technology and quality control of pre-stressed anchor cable retaining wall support method,the prac-tice showed that the support method achieved higher social benefit and economic benefit,worthy of popularization and application.%针对施工场地狭小，拟建建筑物临近公路或其他建筑物的工程项目，在深基坑施工中采用预应力锚索护壁桩支护与不支护放坡开挖进行了对比分析，并对预应力锚索护壁支护法的施工工艺及质量控制作了简述，实践表明该支护方法取得了较高的社会效益和经济效益，值得推广应用。
Institute of Scientific and Technical Information of China (English)
马郧; 徐光黎
2013-01-01
A new retaining structure,namely SMW + reinforced cement soil pile anchor,is put forward to support the soft soil deep excavation pit.It makes full use of the advantages of SMW and pile anchor.The new method can solve the problem of insufficient lateral force in the soft soil and confined environment conditions.The first application in a soft soil excavation pit,which is located in the first Yangtze River's terrace in Wuhan,shows that the new supporting structure is reasonable and effective,not only can provide maximum space for pit and basement construction,but also can ensure the safety of excavation pit and surrounding buildings.It is concluded that SMW + pile anchor retaining structure is a new way for the excavation pit with complex geological conditions and surroundings.%本文提出了SMW+斜向加筋水泥土桩的一种新型支护结构,用于软弱地层、周围环境受限制条件下的基坑工程支护.它充分利用了SMW工法的优点,配以斜向加筋水泥土桩锚支撑,解决了周边环境受限制条件下的侧向抗力不足的问题.在武汉长江Ⅰ级阶地汉口一基坑工程中的首次应用表明,该新型支护结构合理安全,可为基坑及地下室的施工提供最大空间,又可确保了基坑和紧邻周边建筑物的安全,是复杂地质条件与环境下基坑支护的一次非常有益的尝试.
Energy Technology Data Exchange (ETDEWEB)
Levkovich, P.Ye.; Sal' nikov, V.K.; Savich, N.S.
1980-11-30
An anchor reinforcement includes an anchor shaft, an elastic jig with a separator wall having compartments placed parallely along it and filled with reinforcement material and a device for destroying the jig wall separator. To quickly put the anchor in place and increase the reliability of the reinforcement by mixing the reinforcement material components better, the device for destroying the jig separator wall was made in the shape of a shovel, fastened to the anchor shaft and the separator wall has a longitudinal hollow for holding the anchor shaft/shovel.
Optimal Design of Sheet Pile Wall Embedded in Clay
Das, Manas Ranjan; Das, Sarat Kumar
2015-09-01
Sheet pile wall is a type of flexible earth retaining structure used in waterfront offshore structures, river protection work and temporary supports in foundations and excavations. Economy is an essential part of a good engineering design and needs to be considered explicitly in obtaining an optimum section. By considering appropriate embedment depth and sheet pile section it may be possible to achieve better economy. This paper describes optimum design of both cantilever and anchored sheet pile wall penetrating clay using a simple optimization tool Microsoft Excel ® Solver. The detail methodology and its application with examples are presented for cantilever and anchored sheet piles. The effects of soil properties, depth of penetration and variation of ground water table on the optimum design are also discussed. Such a study will help professional while designing the sheet pile wall penetrating clay.
Mooring Anchors for Marine Renewable Energy Foundations
Stevens, Robert F.; Rahim, Amir
2014-01-01
With the increasing use of offshore wind turbines, it has become necessary to explore deep-water sites for locating wind farms. Floating turbines are an ideal choice for these locations. Such turbines are anchored with mooring chains to the sea floor using suction anchors, driven piles or gravity foundations. This paper presents design methods for these types of foundations. Moored gravity foundations have been used for the much larger floating oil and gas installations. These concrete founda...
The tensile capacity of steel pipe piles drilled into the bedrock
Sirén, Rosa
2015-01-01
This Master’s thesis focuses on drilled pipe piles and their ability to transfer tensile forces. The tensile forces affecting pile foundations are usually transferred to the bedrock by rock anchors. If drilled pipe piles could transfer some of these tension forces, foundation work would be faster, easier and more cost-effective. This thesis is a continuation of a study published in 2014, which also investigated the tensile capacity of drilled pipe piles. This thesis consists of two main ...
Institute of Scientific and Technical Information of China (English)
贺星新; 李爱群; 李建慧; 苏骥
2014-01-01
为研究土桩结构相互作用对独塔自锚式悬索桥动力特性及地震响应的影响规律，利用有限元软件Midas/Civil建立了2个空间有限元成桥状态模型，分别采用J．Penzien集中质量模型模拟的桩土边界和承台底部固结边界，并对结构进行了动力特性分析和不同地震工况下的非线性时程分析．研究结果表明，土桩结构相互作用延长了结构自振周期，且对主塔参与的振型影响很大．与基础固结模型相比，考虑土桩结构相互作用的结构在地震作用下的内力响应减小20％左右，而桥塔位移响应增大约50％，主梁位移响应增大约3％．因此，此类结构抗震设计时需基于不同控制目标选择不同的基础处理方式．%To study the influences of soil-pile-structure interaction on the dynamic characteristics and seismic response of a self-anchored suspension bridge with single-tower,two spatial finite element models of this structure were established based on the software Midas/Civil.By using the J.Penzien lumped mass model,one model simulated the soil-pile interaction and the other chose fixed boundary under the pile cap.Then,the dynamic characteristics analysis and nonlinear time history analysis under seismic motions were investigated.The research results show that the soil-pile-structure interaction ex-tends the natural vibration period and has a great influence on the tower dominant vibration model. Compared with the fixed foundation model,the seismic force responses of the structure with soil-pile-structure interaction decrease more than 20%,while the displacement responses on the tower increase about 50%and those on the girder increase about 3%.Thus,during the aseismic design period of this kind of structures,different boundary models should be chosen for different performance objectives.
Design of anti-slide piles for slope stabilization in Wanzhou city, Three Gorges Area, China
Zhou, Chunmei; van Westen, Cees
2013-04-01
This study is related to the design of anti-slide piles for several landslides in Wanzhou city located in the Three Gorges area. Due to the construction of the Three Gorges Reservoir the hydro-geological conditions in this area have deteriorated significantly, leading to larger instability problems. China has invested a lot of money in slope stabilization measures for the treatment of landslides in the Three Gorges area. One of the methods for the stabilization of large landslides is the design of anti-sliding piles. This paper focuses on extensive slope stability analysis and modeling of the mechanical behavior of the landslide masses, and the parameters required for designing the number, size and dimensions of reinforced concrete stabilization piles. The study focuses on determining the rock parameters, anchor depth, and the pile and soil interaction coefficient. The study aims to provide guidelines for anti-slide pile stabilization works for landslides in the Wanzhou area. The research work contains a number of aspects. First a study is carried out on the distribution of pressures expected on the piles, using two different methods that take into account the expected pore water pressure and seismic acceleration. For the Ercengyan landslide , the Limit Equilibrium Method and Strength Reduction Method of FEM are compared through the results of the landslide pressure distributions on the piles and stress fields in the piles. The second component is the study of the required anchor depth of antislide piles, which is carried out using a statistical analysis with data from 20 landslides that have been controlled with anti-sliding piles. The rock characteristics of the anchor locations were obtained using laboratory tests, and a classification of rock mass quality is made for the anchors of antislide piles. The relationship between the critical anchor height and the angle of the landslide slip surface is determined. Two different methods are presented for the length
Horizontal vibrations of piles in a centrifuge
International Nuclear Information System (INIS)
The aim of the thesis is the study of soil dynamics for important structures like nuclear power plants, offshore platforms, dams etc. Experimental results of horizontal vibrations on a pile partially anchored in a soil scale model put into a centrifuge are presented. Mechanical similitude conditions from equilibrium equations or rheologic laws are described. After a description of testing equipment (centrifuge, electrodynamic excitator) experimental results are interpreted with a model. Non-linearities on frequency response curves are characterized
Monitoring ground anchor using non-destructive ground anchor integrity test (NDT-GRANIT)
International Nuclear Information System (INIS)
Monitoring at ground anchor commonly uses a pull out test method, therefor we developing a non-destructive ground anchor integrity testing (NDT-GRANIT). NDT-GRANIT using the principle of seismic waves that have been modified into form of sweep signal, the signal will be demodulated, filtered, and Fourier transformation (inverse discrete Fourier transform) so the data can be interpreted reflected wave from the ground anchor. The method was applied to determine whether the ground anchor still gripped in the subsurface by looking the attenuation of the wave generated sources. From the result we can see that ground anchor does not grip. To validate the results of the comparison method of measurement used pile integrity test
Hsu, Shu-Wei
2010-01-01
We present a method for directly modeling piles of objects in multi-body simulations. Piles of objects represent some of the more interesting, but also most time-consuming portion of simulation. We propose a method for reducing computation in many of these situations by explicitly modeling the piles that the objects may form into. By modeling pile behavior rather than the behavior of all individual objects, we can achieve realistic results in less time, and without directly modeling the frictional component that leads to desired pile shapes. Our method is simple to implement and can be easily integrated with existing rigid body simulations. We observe notable speedups in several rigid body examples, and generate a wider variety of piled structures than possible with strict impulse-based simulation. © 2010 ACM.
International Nuclear Information System (INIS)
The programme of the high flux laboratory pile EL3 was laid down in october 1954. It is a heavy-water moderated and cooled pile. The fuel rods are of uranium metal with 1.6 per cent - 2 per cent of molybdenum, with aluminium canning. The maximum thermal flux in the moderator is 1014 n/cm2/s. Studies began in january 1955, construction in may 1955, and the first divergence took place in July 1957. This report gives a general description of the pile and its adjacent buildings, the physical study of the pile, and certain technological studies carried out for the construction of EL3. (author)
Vertical Equilibrium of Sheet Pile Walls with Emphasis on Toe Capacity and Plugging
DEFF Research Database (Denmark)
Iversen, Kirsten Malte; Augustesen, Anders Hust; Nielsen, Benjaminn Nordahl
Constructions including retaining walls are normally established in areas where it is impossible to conduct an excavation with inclined sides. Due to large excavation depths and due to restrictions on the deformations of the wall, it is often necessary to anchor the wall. The limited space makes it...... at the pile toe to fulfil vertical equilibrium. The paper describes a case study of sheet pile walls in Aalborg Clay, and the amount of loads transferred as point loads at the pile toe for free and anchored walls is estimated. A parametric study is made for the free wall with regards to the height...... and the roughness of the wall. Due to limitations of the calculation method, the study of the anchored wall only includes variation of the roughness. For the case study, it is found that the vertical equilibrium is fulfilled for the considered free wall. An anchored wall needs a plug forming at the...
BEHAVIOR OF LATERALLY LOADED PILE
Ashish Mehta; P.D.Pachpor
2010-01-01
A finite element analysis is done to predict the responses for single pile subjected to lateral load in layered soils, with consideration of pile soil interaction. Pile and soil are simulated by Solid-3D element. In the computational model, contact surfaces between pile and soil are created. The displacements are determined for pile soil system with linearly constants and linearly varying with depth cases is considered. The engineering properties for soil and pile are considered as variable f...
Basal Reinforced Piled Embankments
Van Eekelen, S.J.M.
2015-01-01
A basal reinforced piled embankment consists of a reinforced embankment on a pile foundation. The reinforcement consists of one or more horizontal layers of geosynthetic reinforcement (GR) installed at the base of the embankment. The design of the GR is the subject of this thesis. A basal reinforce
Pile Instrumentation Using Retrievable Sensors
Faisal H. Ali; Bujang B.K. Huat; Lee S. Kai
2008-01-01
Strain gauges are normally used to monitor the shortening or compression of pile during static pile load test. For concrete spun pile, the technique used either by incorporating high temperature-resistant strain gauges into the heat-cured production process of the spun piles or by installing an instrumented steel pipe into the hollow core of the spun piles followed by cement grout infilling. The former is extremely unpopular due to high cost of these gauges and the uncertainty over their abil...
Soil-Pile Interaction in the Pile Vertical Vibration Based on Fictitious Soil-Pile Model
Guodong Deng; Jiasheng Zhang; Wenbing Wu; Xiong Shi; Fei Meng
2014-01-01
By introducing the fictitious soil-pile model, the soil-pile interaction in the pile vertical vibration is investigated. Firstly, assuming the surrounding soil of pile to be viscoelastic material and considering its vertical wave effect, the governing equations of soil-pile system subjected to arbitrary harmonic dynamic force are founded based on the Euler-Bernoulli rod theory. Secondly, the analytical solution of velocity response in frequency domain and its corresponding semianalytical solu...
Soil-Pile Interaction in the Pile Vertical Vibration Based on Fictitious Soil-Pile Model
Directory of Open Access Journals (Sweden)
Guodong Deng
2014-01-01
Full Text Available By introducing the fictitious soil-pile model, the soil-pile interaction in the pile vertical vibration is investigated. Firstly, assuming the surrounding soil of pile to be viscoelastic material and considering its vertical wave effect, the governing equations of soil-pile system subjected to arbitrary harmonic dynamic force are founded based on the Euler-Bernoulli rod theory. Secondly, the analytical solution of velocity response in frequency domain and its corresponding semianalytical solution of velocity response in time domain are derived by means of Laplace transform technique and separation of variables technique. Based on the obtained solutions, the influence of parameters of pile end soil on the dynamic response is studied in detail for different designing parameters of pile. Lastly, the fictitious soil-pile model and other pile end soil supporting models are compared. It is shown that the dynamic response obtained by the fictitious soil-pile model is among the dynamic responses obtained by other existing models if there are appropriate material parameters and thickness of pile end soil for the fictitious soil-pile model.
Hypersensitivity to Suture Anchors
Directory of Open Access Journals (Sweden)
Masafumi Goto
2013-01-01
Full Text Available Hypersensitivity to suture anchor is extremely rare. Herein, we present a case in which hypersensitivity to suture anchor was strongly suspected. The right rotator cuff of a 50-year-old woman was repaired with a metal suture anchor. Three weeks after the surgery, she developed erythema around her face, trunk, and hands, accompanied by itching. Infection was unlikely because no abnormalities were detected by blood testing or by medical examination. Suspicious of a metallic allergy, a dermatologist performed a patch testing 6 months after the first surgery. The patient had negative reactions to tests for titanium, aluminum, and vanadium, which were the principal components of the suture anchor. The anchor was removed 7 months after the first surgery, and the erythema disappeared immediately. When allergic symptoms occur and persist after the use of a metal anchor, removal should be considered as a treatment option even if the patch test result is negative.
Pile Instrumentation Using Retrievable Sensors
Directory of Open Access Journals (Sweden)
Faisal H. Ali
2008-01-01
Full Text Available Strain gauges are normally used to monitor the shortening or compression of pile during static pile load test. For concrete spun pile, the technique used either by incorporating high temperature-resistant strain gauges into the heat-cured production process of the spun piles or by installing an instrumented steel pipe into the hollow core of the spun piles followed by cement grout infilling. The former is extremely unpopular due to high cost of these gauges and the uncertainty over their ability to survive the pile production and driving processes. The shortcoming of the other technique is the infilling of cement grout substantially alters the structural properties of the piles, thus rendering their load-response behaviour significantly different from that of the actual working piles. To address the difficulties of the above techniques a new method was recently developed by the authors, which uses retrieval sensors instead of strain gauges (which have to be sacrificed in every test. The method also has the ability to monitor loads and displacements at various levels along the pile shaft and toe of instrumented piles. Results of field tests show high quality, reliable and consistent data, clearly far exceeding the capability of both conventional and approximate methods of using strain gauges.
Grouting for Pile Foundation Improvement
Van der Stoel, A.E.C.
2001-01-01
The aim of this research was to examine the use of grouting methods for pile foundation improvement, a generic term that is used here to define both foundation renovation (increasing the bearing capacity of a pile foundation that has insufficient bearing capacity) and foundation protection (safeguarding the piles of the foundation against possible damage resulting from underground construction activities in the vicinity). A full-scale test, of which the general set-up and consistency check ar...
Susceptibility to anchoring effects
Directory of Open Access Journals (Sweden)
Todd McElroy
2007-02-01
Full Text Available Previous research on anchoring has shown this heuristic to be a very robust psychological phenomenon ubiquitous across many domains of human judgment and decision-making. Despite the prevalence of anchoring effects, researchers have only recently begun to investigate the underlying factors responsible for how and in what ways a person is susceptible to them. This paper examines how one such factor, the Big-Five personality trait of openness-to-experience, influences the effect of previously presented anchors on participants' judgments. Our findings indicate that participants high in openness-to-experience were significantly more influenced by anchoring cues relative to participants low in this trait. These findings were consistent across two different types of anchoring tasks providing convergent evidence for our hypothesis.
Piled Embankment Design Comparison
Directory of Open Access Journals (Sweden)
Drusa Marián
2015-05-01
Full Text Available There are currently several national standards or regulations for the design of the piled embankment, providing suitable solutions for foundation of transport structure on soft, high compressible subsoil, [1]. The most widely used and the best-known standard is British Standard BS8006 [2], which was confronted with another analytical design methodologies (Ebgeo, CUR. Today’s popularity and versatility of FEM numerical models brings many advantages, which analytical methods cannot achieved, but must be verified by proposed scaled physical model, which was currently being developed by Department of Geotechnics, University of Žilina.
Piled Embankment Design Comparison
Drusa, Marián; Kais, Ladislav; Vlček, Jozef; Mečár, Martin
2015-05-01
There are currently several national standards or regulations for the design of the piled embankment, providing suitable solutions for foundation of transport structure on soft, high compressible subsoil, [1]. The most widely used and the best-known standard is British Standard BS8006 [2], which was confronted with another analytical design methodologies (Ebgeo, CUR). Today's popularity and versatility of FEM numerical models brings many advantages, which analytical methods cannot achieved, but must be verified by proposed scaled physical model, which was currently being developed by Department of Geotechnics, University of Žilina.
Pressured Grouting Method (PGM) in Pile Engineering
Institute of Scientific and Technical Information of China (English)
吴兴序; 于志强; 王旭
2002-01-01
Application of pressured grouting method (PGM) in pile engineering can tackle problems encountered during construction of bored piles. Bearing capacity of piles can be increased through compaction of subsoils around piles. This paper reports research efforts of this technique by the pile research team in Southwest Jiaotong University in last decade with respect to the construction process, test findings, and primary research conclusions. The social-economical benefits of this method and application market in pile engineering are also analyzed.
Anchoring visions in organizations
DEFF Research Database (Denmark)
Simonsen, Jesper
1999-01-01
This paper introduces the term 'anchoring' within systems development: Visions, developed through early systems design within an organization, need to be deeply rooted in the organization. A vision's rationale needs to be understood by those who decide if the vision should be implemented as well as...... anchoring is considered to be a main activity, is outlined. The task of anchoring visions is described, and techniques and activities are suggested with respect to those actors that have to act on the visions and the recommendations from a design proposal. The paper concludes that obtaining appropriate...
Finite element analysis of soil-sheet pile interaction
Nyby, D. W.
A finite element model which accurately and economically models soil-sheet pile structures was developed. The model was used to analyze cantilever and anchored sheet pile walls. The finite element model includes transition and interface elements. The transition element has the capability of conforming to the displaced shape of the sheet pile elements on one side (cubic element) and soil elements on the other sides (bilinear element). The interface element models the frictional resistance between the soil and the sheet pile. It behaves elastically below a threshold force level (Coulomb friction) and perfectly plastic above this value. The soil is modeled using nonlinear constitutive relations. These relations are used for both the transition elements and the bilinear elements. The economy of the finite element model was increased in two ways. Closed-form integration was used to reduce the computational effort and an equation solver was used which takes advantage of the banded, symmetric, and positive-definite characteristics of the global stiffness matrix.
Susceptibility to anchoring effects
Todd McElroy; Keith Dowd
2007-01-01
Previous research on anchoring has shown this heuristic to be a very robust psychological phenomenon ubiquitous across many domains of human judgment and decision-making. Despite the prevalence of anchoring effects, researchers have only recently begun to investigate the underlying factors responsible for how and in what ways a person is susceptible to them. This paper examines how one such factor, the Big-Five personality trait of openness-to-experience, influences the effect of previously p...
Grouted Pile and Its Bearing Capacity
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The grouting method applied in bored pile is an improvement to the conventional bored pile. Load tests have proved that grouting under the bored pile tip is an effective method to enhance the bearing capacity of the pile and to reduce the pile settlement. In this paper, the grouting technology is described and pile-load test results are discussed. In order to put the grouting method into design practice, the authors analyze the working mechanism of soil compaction. And, based on the theory of cavities expansion in soil mass, approximate formulae are proposed for estimating the bearing capacity of the grouted pile. The theoretical prediction agrees well with the load test results.
Settlement and bearingcapacity of long pile
Ter-Martirosyan Zaven Grigor’evich; Ter-Martirosyan Armen Zavenovich; Trinh Tuan Viet; Luzin Ivan Nikolaevich
2015-01-01
When a long pile is interacting with the soil, the combined force applied to the pile head is distributed among the side face and the pile toe inhomogeneously. The toe gets not more than 30 % from the general force, which doesn’t let using the reserves of the bearing capacity of relatively firm soil under the fifth pile. Account for the depth of the pile toe and the dead load of the soil allows increasing the bearing capacity of the soil under the pile toe and decrease the pile settlement in ...
Viscoelastic behavior of concrete pile
Institute of Scientific and Technical Information of China (English)
丁科; 唐小弟
2008-01-01
Based on constitutive theory of viscoelasticity,the viscoelastic behaviour of concrete pile was investigated.The influence of viscosity coefficient on the stress,displacement and velocity response was discussed.With the increase of viscosity coefficient,the amplitude of stress wave decreases,and the maximum value of the stress wave shifts to deeper position of the pile.In other words,the viscosity coefficient behaves as lag effect to stress wave.
Simulation analysis for O-cell test of pile and the interaction of upper pile and lower pile
Institute of Scientific and Technical Information of China (English)
ZHENG Ying-jie; ZHANG Ke-xu; ZHANG Er-qi
2009-01-01
In this paper, the soil-pile system of O-cell test of pile is simplified as an axi-symmetrie problem.By using aggregation of quadrilateral isoparametrie elements to simulate pile and soil, setting Goodman' s elements between pile and soils, a method of numerical simulation analysis on O-cell test of pile is presented with the consideration of nonlinear mechanical behavior of soils and pile-soil interface.The method is applied to the a-nalysis of a case of O-cell test of pile.The load-displacement curves and axial force curves of upper pile and lower pile obtained from the O-cell test of pile are fitted, and parameters of the mechanical model of soils and interface are determined.Analysis results validate that the numerical simulation analysis method put forward in this paper is applicable.Furthermore, the interaction and influence of upper pile and lower pile in the O-cell test are also studied with the method.The result shows that if load box is located in a soil layer with fine me-chanical behavior, the interaction of upper pile and lower pile in O-cell test can be ignored generally.
Anchoring the Deficit of the Anchor Deficit: Dyslexia or Attention?
Willburger, Edith; Landerl, Karin
2010-01-01
In the anchoring deficit hypothesis of dyslexia ("Trends Cogn. Sci.", 2007; 11: 458-465), it is proposed that perceptual problems arise from the lack of forming a perceptual anchor for repeatedly presented stimuli. A study designed to explicitly test the specificity of the anchoring deficit for dyslexia is presented. Four groups, representing all…
Analysis of Interaction Factors Between Two Piles
Institute of Scientific and Technical Information of China (English)
CAO Ming; CHEN Long-zhu
2008-01-01
A rigorous analytical method is presented for calculating the interaction factor between two identical piles subjected to vertical loads. Following the technique proposed by Muki and Sternberg, the problem is decomposed into an extended soil mass and two fictitious piles characterized respectively by Young's modulus of the soil and that of the difference between the pile and soil. The unknown axial forces along fictitious piles are determined by solving a Fredholm integral equation of the second kind, which imposes the compatibility condition that the axial strains of the fictitious piles are equal to those corresponding to the centroidal axes of the extended soil. The real pile forces and displacements can subequally be calculated based on the determined fictitious pile forces, and finally, the desired pile interaction factors may be obtained. Results confirm the validity of the proposed approach and portray the influence of the governing parameters on the pile interaction.
Axially Loaded Behavior of Driven PC Piles
Hsu, Shih-Tsung
2010-05-01
To obtain a fair load-settlement curve of a driven pile, and to evaluate the ultimate pile capacity more accurately, a numerical model was created to simulate the ground movements during a pile being driven. After the procedure, the axially loaded behaviors of the piles in silty sand were analyzed. The numerical results are compared with those results by full scale pile load tests. It was found, although the loads added on the tested piles are different from those by the numerical analyses which applied displacement increments on piles, the load-settlement behaviors of piles calculated from the numerical model were close to those measured from field tests before the piles stressed to peak. Total load, shaft friction, and point bearing do not reach peak values at the same pile settlement; furthermore, the point bearing slowly increases all the while, with no peak. However, the point bearing only contributes 10˜20% of ultimate pile capacity. No matter which relative density of silty sand, pile diameter, and pile length increased, ultimate pile capacity increased as well.
Ultimate limit state design of sheet pile walls by finite elements and nonlinear programming
DEFF Research Database (Denmark)
Krabbenhøft, Kristian; Damkilde, Lars; Krabbenhøft, Sven
2005-01-01
The design of sheet pile walls by lower bound limit analysis is considered. The design problem involves the determination of the necessary yield moment of the wall, the wall depth and the anchor force such that the structure is able to sustain the given loads. This problem is formulated as a nonl......The design of sheet pile walls by lower bound limit analysis is considered. The design problem involves the determination of the necessary yield moment of the wall, the wall depth and the anchor force such that the structure is able to sustain the given loads. This problem is formulated...... as a nonlinear programming problem where the yield moment of the wall is minimized subject to equilibrium and yield conditions. The finite element discretization used enables exact fulfillment of these conditions and thus, according to the lower bound theorem, the solutions are safe....
Ultimate Limit State Design Of Sheet Pile Walls By Finite Elements And Nonlinear Programming
DEFF Research Database (Denmark)
Krabbenhøft, Kristian; Damkilde, Lars; Krabbenhøft, Sven
2005-01-01
The design of sheet pile walls by lower bound limit analysis is considered. The design problem involves the determination of the necessary yield moment of the wall, the wall depth and the anchor force such that the structure is able to sustain the given loads. This problem is formulated as a nonl......The design of sheet pile walls by lower bound limit analysis is considered. The design problem involves the determination of the necessary yield moment of the wall, the wall depth and the anchor force such that the structure is able to sustain the given loads. This problem is formulated...... as a nonlinear programming problem where the yield moment of the wall is minimized subject to equilibrium and yield conditions. The finite element discretization used enables exact fulfillment of these conditions and thus, according to the lower bound theorem, the solutions are safe...
Energy piles. A fundamental energy pile; Energiepfaehle. Eine fundamentale Energiequelle
Energy Technology Data Exchange (ETDEWEB)
Kaiser, Holger; Beldermann, Nico [GF-Tec GmbH, Roedermark (Germany)
2013-03-01
The Maintower, the new airport in Berlin/Brandenburg, a lot of Ikea buildings, and also small office buildings or residential buildings may exchange energy with the underground by means of pile fundaments. At the correct planning and execution, energy piles are low-cost geothermal power plants which sustainable generate heating and cooling for the buildings standing on them. Even more energy can be generated safely under compliance with the groundwater protection by means of a new development of the material and the transfer.
Instrumented model pile tests on sand plugs
Energy Technology Data Exchange (ETDEWEB)
Haaren, L.J.C. van; Verruijt, A. [Delft Univ. of Technology (Netherlands); Kolk, H.J. [Fugro Engineers B.V., Leidschendam (Netherlands)
1995-12-31
0pen ended piles develop internal frictional resistance between the internal soil plug end the pile wall during axial loading. Current pipe pile design practice assumes that the ultimate internal skin friction is of the same order of magnitude as the outer skin friction. This paper describes a series of laboratory pile load tests on instrumented model pipe piles, designed to investigate the development of plug stresses and skin friction along the plug length during pile loading. The piles contain sand columns of various relative densities and of different heights. The soil plugs are loaded to failure under fully drained conditions. The test data indicate that internal skin friction in sand can be substantially higher than assumed in conventional design practice. This finding could lead to significant economical savings on future pipe pile foundations in sand.
Influence of vertical loads on lateral pile group response considering soil-pile-cap interactions
Hussien, Mahmoud N.; Tobita, Tetsuo; Iai, Susumu
This paper presents the results of a numerical investigation conducted to study the effect of vertical loads on lateral response of a free head and a capped pile group in sand. A coupled soil-pile system is idealized through 2D finite elements with soil models idealized by a hyperbolic type multiple shear mechanism. The analysis focuses on the five piles in the middle row of a 3x5 pile group spaced at 3.92-pile diameters. The interaction between a pile and the surrounding soil in the 3D type is idealized in the 2D analysis using soil-pile interaction springs with a hysteretic non-linear load displacement relationship. The presence of vertical loads on free head piles increases the confining pressures in the sand deposit confined by the piles but the rate of increase in those outside the group is relatively small, resulting in the difference in a balance of lateral soil pressures acting at the back of and in front of individual piles. A vertical load applied to a group pile with a uniform vertical displacement of 0.1 pile diameter decreases the lateral resistance of the leading pile (pile 1) by 10 % and increases the lateral resistance of piles 3 and 5 by 14 and 35 %, respectively. The same trend with higher percentages of increase or decrease is observed in the capped pile group case.
Analysis of pile foundations under dynamic loads
International Nuclear Information System (INIS)
A method is presented for the analysis of pile foundations which are subjected to horizontal dynamic loads from earthquakes, airplane impact, gas explosion or other sources. The motion of the pile cap and the pile forces are computed. - The loads may be applied to the pile cap or directly to the piles (e.g. by earthquake wave motion). The soil may be stratified and is considered to be an elastic or visco-elastic medium. The piles are assumed vertical. The method makes use of an approximate fundamental solution for displacements caused by a dynamic point load in a layered visco-elastic medium. The approximation involves a discretization of the medium in the vertical direction. In horizontal directions the medium is treated by continuum theory. The soil medium supports each pile at about 10 to 20 nodes. A dynamic flexiblity matrix for the soil is derived which relates the elastic, damping and inertial forces of the soil to the displacements at each node. It includes effects of radiation damping. All piles are coupled through the soil flexibility matrix. The piles are modelled by beam elements. Transient response is computed using fast discrete Fourier transforms. The arrangement of the piles is arbitrary. However, simple and double symmetry can be accounted for by the computer program. When the pile arrangement is axisymmetric, the degrees of freedom can be reduced to only those of two piles per ring. The influence of the number of piles and the influence of the pile spacing on group stiffness and on pile forces is presented for two soil profiles. Dynamic effects on pile forces of a foundation for a reactor building are studied. They are significant when soils are soft. (orig.)
Directory of Open Access Journals (Sweden)
Ter-Martirosyan ZavenGrigorevich
2012-10-01
It is proven that the above properties produce a substantial impact onto the stress-strain state of soils that interact with the pile and the grid, and the impact values make it possible to assess the rigidity of the slab-pile foundation that is needed to solve the problems of the multiplicity of piles as well as the problems of distribution of the total load between the piles and the grid.
Settlement and bearingcapacity of long pile
Directory of Open Access Journals (Sweden)
Ter-Martirosyan Zaven Grigor’evich
2015-05-01
Full Text Available When a long pile is interacting with the soil, the combined force applied to the pile head is distributed among the side face and the pile toe inhomogeneously. The toe gets not more than 30 % from the general force, which doesn’t let using the reserves of the bearing capacity of relatively firm soil under the fifth pile. Account for the depth of the pile toe and the dead load of the soil allows increasing the bearing capacity of the soil under the pile toe and decrease the pile settlement in general. For the quantitative estimation of these factors it is necessary to solve the task on the interaction of the rigid long pile with the surrounding soil, which includes under the pile toe, which is absolutely rigid round stamp.The article presents the formulation and analytical solution to a quantification of the settlement of a circular foundation with the due account for its depth, basing on the development of P. Mindlin’s studies as well as the interactions between a long rigid pile and surrounding soils, including under pile toe.It is proposed to compare the estimated value of stresses under the heel of pile with the initial critical load for the round foundation to check the condition that the estinated value is less than the intial critical one.
International Nuclear Information System (INIS)
The energy spectrum containing the effects of all orders of pulse pileup is predicted for an idealized x-ray pulse-height-analysis system measuring randomly occurring events. Two simplifying assumptions used are first a fixed pulse resolution time and second that the measured energy of piled-up pulses is the algebraic sum of the energy associated with each pulse
Decommissioning of Windscale pile 1
International Nuclear Information System (INIS)
The Windscale Piles were constructed in the late 1940's primarily for the production of plutonium in support of the British atomic weapons programme. In 1957 Pile 1 suffered a fire during the routine release of stored Wigner energy by nuclear heating. Following the fire as much material as possible was recovered, an inventory and status report prepared and the pile sealed and placed under surveillance and maintenance, the only practicable option at the time. Over the last decade in addition to general improvements in routine monitoring equipment there has been extensive investigative work carried out to better understand the damage caused by the fire and assess the options for further action. These studies concluded that the preferred option was for the Pile core to be removed, treated and packaged for intermediate storage prior to final disposal. The paper will describe the core investigations, the assessed conditions, and the options considered. It will also describe the tendering process to allow contractors to propose solutions against a cardinal point specification, the outline of the preferred solution and the progress of the work to date. (author)
Pullout capacity of batter pile in sand
Directory of Open Access Journals (Sweden)
Ashraf Nazir
2013-03-01
Full Text Available Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21–31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18–75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.
DRIVEN POLYSTRONG REINFORCED CONCRETE PILES AND NEW DESIGN OF PILE CAPS
Directory of Open Access Journals (Sweden)
I. I. Bekbasarov
2015-05-01
Full Text Available The paper presents constructional and technological features for manufacturing driven piles with variable strength of pile shaft. Economical efficiency of their production has been shown in the paper. The paper provides a pile cap design that ensures perception of hammer impacts with the help of lateral edges of the pile cap. Driven reinforced concrete piles which are manufactured from three shaft sections having various strength have been proposed in the paper. Material strength (concrete grade and diameter of bars and length of shaft sections are given on a case by case basis in accordance with nature and rate of stresses in piles during their driving process. Manufacturing of polystrong piles provides an opportunity to select them for a particular construction site with due account of their preservation during driving process.A pile cap has been developed that as opposed to existing analogous designs makes it possible to transmit impact efforts from a hammer to the pile through lateral surface of its head part. The pile cap provides the possibility to increase an area for perception of hammer impact efforts by the pile and in doing so it is possible significantly to reduce a damage risk and destruction of pile concrete during its driving. Application of polystrong piles and their driving with the help of new pile cap are considered as a basis for defect-free and resource-saving technology for pile foundations in the construction.
Pile Load Capacity – Calculation Methods
Directory of Open Access Journals (Sweden)
Wrana Bogumił
2015-12-01
Full Text Available The article is a review of the current problems of the foundation pile capacity calculations. The article considers the main principles of pile capacity calculations presented in Eurocode 7 and other methods with adequate explanations. Two main methods are presented: α – method used to calculate the short-term load capacity of piles in cohesive soils and β – method used to calculate the long-term load capacity of piles in both cohesive and cohesionless soils. Moreover, methods based on cone CPTu result are presented as well as the pile capacity problem based on static tests.
DEFF Research Database (Denmark)
Simonsen, Jesper
1998-01-01
This paper introduces the term 'anchoring' within systems development: Visions, developed through early systems design within an organization, need to be deeply rooted in the organization. A vision's rationale needs to be understood by those who decide if the vision should be implemented as well as...... by those involved in the actual implementation. A model depicting a recent trend within systems development is presented: Organizations rely on purchasing generic software products and/or software development outsourced to external contractors. A contemporary method for participatory design, where...
Pile Model Tests Using Strain Gauge Technology
Directory of Open Access Journals (Sweden)
Krasiński Adam
2015-09-01
Full Text Available Ordinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine the total bearing capacity of the pile, without the knowledge of its distribution into the shaft and base resistances. Much more information can be obtained by carrying out a test of instrumented pile equipped with a system for measuring the distribution of axial force along its core. In the case of pile model tests the use of such measurement is difficult due to small scale of the model.
Thermal Conductivity Of Rubble Piles
Luan, Jing
2015-01-01
Rubble piles are a common feature of solar system bodies. They are composed of monolithic elements of ice or rock bound by gravity. Voids occupy a significant fraction of the volume of a rubble pile. They can exist up to pressure $P\\approx \\epsy\\mu$, where $\\epsy$ is the monolithic material's yield strain and $\\mu$ its rigidity. At low $P$, contacts between neighboring elements are confined to a small fraction of their surface areas. As a result, the effective thermal conductivity of a rubble pile, $\\kcon\\approx k(P/(\\epsy\\mu))^{1/2}$, can be orders of magnitude smaller than, $k$, the thermal conductivity of its monolithic elements. In a fluid-free environment, only radiation can transfer energy across voids. It contributes an additional component, $\\krad=16\\ell\\sigma T^3/3$, to the total effective conductivity, $\\keff=\\kcon +\\krad$. Here $\\ell$, the inverse of the opacity per unit volume, is of order the size of the elements and voids. An important distinction between $\\kcon$ and $\\krad$ is that the former i...
Optimization Mathematical Model of Pile Forces for Offshore Piled Breasting Dolphins
Institute of Scientific and Technical Information of China (English)
周锡礽; 王东芹; 王晖; 朱福明
2004-01-01
An optimization mathematical model of the pile forces for piled breasting dolphins in the open sea under various loading conditions is presented. The optimum layout with the well distributed pile forces and the least number of piles is achieved by the multiplier penalty function method. Several engineering cases have been calculated and compared with the result of the conventional design method. It is shown that the number of piles can be reduced at least by 10% ～ 20%and the piles' bearing state is improved greatly.
Analysis of the Effect of Pile Skin Resistance Verses Pile Diameter Based on Experimental Research
Directory of Open Access Journals (Sweden)
S. M. Marandi
2009-01-01
Full Text Available In spite of the many recent advances in pile design and execution methods, the quantitative effects of grouted pile skin resistance and form on subsequent pile behavior remains an area for research. There are many parameters involved in the analysis of the bearing capacity of piles and descriptive method theory of the loading effect for each parameter is very complex. Many of these parameters are interrelated and investigation of the relationships leads to complex equations, which cannot be easily solved. The only reliable solution is to study the influence of each parameter by experimental model tests in equipped laboratories. This research presents the results of static compression tests on two model groups of pipe and grouted pile shafts (35mm, 50mm and 60 mm in diameters and 900 mm in length installed into beds of Yazd siliceous sand (located in southeast Iran. The findings of the experimental research were to the average ultimate loads at failure for grouted piles were approximately 12% higher than for the pipe piles. The pile skin resistance is an effective factor on pile bearing capacity, the load transfer response appears to be more plastic with increasing pile diameter in siliceous sand and the skin resistance of the pile was not linearly proportional to the pile diameter and varied with increase in pile diameter.
Pile Model Tests Using Strain Gauge Technology
Krasiński, Adam; Kusio, Tomasz
2015-09-01
Ordinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine the total bearing capacity of the pile, without the knowledge of its distribution into the shaft and base resistances. Much more information can be obtained by carrying out a test of instrumented pile equipped with a system for measuring the distribution of axial force along its core. In the case of pile model tests the use of such measurement is difficult due to small scale of the model. To find a suitable solution for axial force measurement, which could be applied to small scale model piles, we had to take into account the following requirements: - a linear and stable relationship between measured and physical values, - the force measurement accuracy of about 0.1 kN, - the range of measured forces up to 30 kN, - resistance of measuring gauges against aggressive counteraction of concrete mortar and against moisture, - insensitivity to pile bending, - economical factor. These requirements can be fulfilled by strain gauge sensors if an appropriate methodology is used for test preparation (Hoffmann [1]). In this paper, we focus on some aspects of the application of strain gauge sensors for model pile tests. The efficiency of the method is proved on the examples of static load tests carried out on SDP model piles acting as single piles and in a group.
Numerical Modeling of Laterally Loaded Piles
S. T. Kok; B. B.k. Huat
2008-01-01
Design of laterally loaded piles due to soil movement relies on a number of theoretical and numerical approaches. However, the magnitude of soil movement is difficult to estimate with reasonable confidence and accuracy. Finite Element Analysis (FEA) offers an excellent alternative to study pile-soil interaction and piles response under lateral loading due to soil movement. This research presents published analytical results and case history modeled in a 2D finite element environment in the ca...
Suro, S. M.; Bakar, I.; Sulaeman, A.
2016-07-01
Short Piled Raft is a modified piled raft foundation system, which represents combination between raft foundation and pile foundation, but the length of pile is relatively shorter. The basic concept of the Short Piled Raft foundation system considers the passive soil pressure creating a stiff condition of slab-pile system. This means that the thin concrete slab floats on the supporting soil, while the piles serve as stiffeners concrete slab and also to reduce settlement of the foundation. Slab to pile ratio of such system has been mentioned by several researchers, however the optimum pile spacing of stability performance for obtaining minimum settlement on peat haven't been clearly discussed. In this study, finite element method to simulate the stability performance related to settlement of Short Piled Raft foundation system was used. Short Piled Raft foundation system with concrete slab of 7.0 m x 7.0 m square was assumed to be built on peat with the thickness of 3.5 m. The material properties of pile and raft were constant. The outer diameter of galvanized steel pipe as pile was 0.30 m; raft thickness was considered to be constant of 0.15 m and the length of pile was 3.0 m, while the pile spacing varied from 0.50 to 3.00 m. Point load varied from 0 to 100 kN with increment of 20 kN was also considered as a static load, acted on the centre of the concrete slab. Optimization was done by comparing each numerical result of simulations, thus conclusion can easily be drawn. The optimum pile spacing was 1.00 m which produced minimum settlement of 30.11 mm under the load of 100 kN.
Safety precautions in atomic pile control (1962)
International Nuclear Information System (INIS)
We have been led to study the problem of safety in atomic pile control as a result of our participation on the one hand in the planning of C.E.A. atomic piles, and on the other hand in the pile safety sub omission considering atomic pile safety of operational or planned C.E.A. piles. We have thus had to consider the wishes occurring in piles during their operation and also their behaviour in the dynamic state The present work deals mainly with the importance of intrinsic safety devices, with the influence of reactivity variations on the power fluctuations during accidental operation, and with the development of robust and reliable safety appliances. The starting p accident has been especially studied both for low-flux piles where a compromise is necessary between the response time of the safety appliances and the statistical fluctuations and for high lux piles where xenon poisoning has an effect on the lower limit of the velocity of reactivity liberation. The desirability has been stressed of automation as a safety factor in atomic pile control. The details required for an understanding of the diagrams of the apparatus are given. (author)
Point resistance of piles in sand
Miura, Norihiko
1983-01-01
Mechanism of point resistance of pile in sand was investigated mainly from the viewpoint of the particle-crushing of sand at the pile tip. It is shown that the work dissipated in the particle-crushing of sand is as large as 66 percent of the total work done by the external force, hence the point resistance of a pile in sand greatly depends on the particle-crushing property of the sand. It is also shown that the relationship between point resistance and vertical pressure of a pile can be predi...
Soil stress field around driven piles
Allard, Marie-Agnes
1989-01-01
The description, equipment, and results of a series of pile-driving experiments conducted in a centrifuge using a model pile driven in dry sand are presented. The work was conceived on the basis of the modelling of a soil-structure system under an artificially generated gravitational field, and motivated by the need for experimental data for a better understanding of the complex phenomena involved in the pile-soil interaction during driving. The behavior of the pile itself has been the fo...
Influence of reaction piles on test pile response in a static load test
Institute of Scientific and Technical Information of China (English)
Qian-qing ZHANG; Shu-cai LI; Zhong-miao ZHANG
2013-01-01
This work presents a new analytical method to analyze the influence of reaction piles on the test pile response in a static load test.In our method,the interactive effect between soil and pile is simulated using independent springs and the shear displacement method is adopted to analyze the influence of reaction piles on test pile response.Moreover,the influence of the sheltering effect between reaction piles and test pile on the test pile response is taken into account.Two cases are analyzed to verify the rationality and efficiency of the present method.This method can be easily extended to a nonlinear response of an influenced test pile embedded in a multilayered soil,and the validity is also demonstrated using centrifuge model tests and a computer program presented in the literature.The present analyses indicate that the proposed method will lead to an underestimation of the test pile settlement in a static load test if the influence of the presence of reaction piles on the test pile response is neglected.
In-Pile instrumentation development
International Nuclear Information System (INIS)
A proper interpretation of data from advanced irradiations in research reactors requires the on-line monitoring of neutron fluxes, gamma dose rates, central fuel rod temperatures, fission gas release pressures, small geometry changes, etc. Our activities in this field aim at a thorough understanding of the sensors' behaviour under the irradiation conditions in order to extract reliable real-time information. The objectives of the work reported upon are On-line in-pile measurement of thermal and fast neutron fluxes and gamma heating rate and to study parasitic currents and voltages in instrumentation cables due to radiation and temperature effects
Bone Anchored Hearing Treatment Procedure
Full Text Available ... skin to allow removal of some of the soft tissue where the screwlike fixture will be anchored. The ... screen, acting as a hinge. Beneath that the soft tissue consisting of fat and some muscle is removed. ...
Bone Anchored Hearing Treatment Procedure
Full Text Available ... to allow removal of some of the soft tissue where the screwlike fixture will be anchored. The ... series of slides demonstrates the removal of the tissue beneath the skin flap. You can see in ...
Bone Anchored Hearing Treatment Procedure
Full Text Available ... The Baha system consists of a bone-anchored titanium fixture that is implanted in the mastoid bone, ... the -- great. I'm going to grab the titanium implant. And what I want you to notice ...
Bone Anchored Hearing Treatment Procedure
Full Text Available ... of the bone oscillator is superficial on the skin, the transference of that energy is less efficient, ... slides, is to mark the location in the skin where the screwlike fixture will be anchored. Subsequent ...
Grouted jetted precast concrete sheet piles: Method, experiments, and applications
Xu, GH; Yue, ZQ; Liu, DF; He, FR
2006-01-01
This paper introduces an innovative technology - grouted jetted precast concrete piling - that increases the efficiency of piling operations in coastal regions. The technology includes the following steps: (i) casting concrete piles factory-designed especially for jetting and grouting; (ii) jetting to drive the concrete piles with a crane on a floating ship or platform into soil; and (iii) grouting to enhance the sheet pile connections and to increase the pile bearing capacity. This technolog...
Tension Tests On Bored Piles In Sand
DEFF Research Database (Denmark)
Krabbenhøft, Sven; Clausen, Johan; Damkilde, Lars
2006-01-01
The lengths of the bored piles varied from 2 m to 6 m and all were of a diameter of 140 mm. The piles were tested to failure in tension and the load-displacement relations were recorded. The investigation has shown pronounced differences between the load bearing capacities obtained by different d...
Steel Sheet Pile Walls in Soft Soil
Kort, D.A.
2002-01-01
For almost a century, steel sheet pile walls are applied worldwide as earth retaining structures for excavations and quay walls. Within the framework of the development of European structural codes for Civil Engineering works, the Eurocodes, Eurocode 3 Part 5 for design of steel sheet pile walls was
Effect of pile-cap connection on behavior of torsionally loaded pile groups
Institute of Scientific and Technical Information of China (English)
Ling-gang KONG; Li-min ZHANG
2008-01-01
To evaluate the respouses of fixed and pinned pile groups under torsiun, a method is presented to analyze the nonlinear behavior of free-standing pile groups with rigid pile caps. The method is capable of simulating the nonlinear soil response in the near field usingp-y and τ-θ curves, the far-field interactions through Mindlin's and Randolph's elastic solutions, and the coupling effect of lateral resistance on torsional resistance of the individual piles using an empirical factor. Based on comparisons of the solutions for fixedand pinned-head, 1×2, 2×2, and 3×3 pile groups subjected to torsion, it was found that pile-cap connection significantly influences the torsional capacity of pile groups and the assignment of applied torques in the pile groups. In this study, the applied torques for the pinned-head pile groups are only 44%～64% of those for the corresponding fixed-head pile groups at a twist angle of 2°. Such a difference is mainly due to the change of the lateral resistances of individual piles in the groups.
A Study of Horizontal Displacement of Laterally Loaded Piles
Directory of Open Access Journals (Sweden)
Aram M. Raheem
2013-05-01
Full Text Available A theoretical approach is used to analyze single pile and pile in group under lateral loading using two programs. The first one used the finite element method for single pile depending on plain strain condition while the second one used the characteristic load method for pile in group. Horizontal displacement for pile in group is measured while both horizontal displacement and shear stress for single pile are measured. A comparison between the results of horizontal displacement for both single pile and pile in group with the actual practical values are produced and shows a good agreement.
Model Tests of Pile Defect Detection
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The pile, as an important foundation style, is being used in engineering practice. Defects of different types and damages of different degrees easily occur during the process of pile construction. So,dietecting defects of the pile is very important. As so far, there are some difficult problems in pile defect detection. Based on stress wave theory, some of these typical difficult problems were studied through model tests. The analyses of the test results are carried out and some significant results of the low-strain method are obtained, when a pile has a gradually-decreasing crosssection part, the amplitude of the reflective signal originating from the defect is dependent on the decreasing value of the rate of crosssection β. No apparent signal reflected from the necking appeares on the velocity response curve when the value of β is less than about 3.5 %.
Investigation on the Effect of Drained Strength when Designing Sheet Pile Walls
DEFF Research Database (Denmark)
Iversen, Kirsten Malte; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust
the height, anchor force, and the maximum bending moment in the wall can be lowered significantly when the effective cohesion is increased above zero. However, as the cohesion increases, the drop in the moment levels off, which implies that the benefit obtained from investigations increasing the......Long sheet pile walls are constructed in the cities as an integrated part of deep excavations for e.g. parking lots, pumping stations, reservoirs, and cut and cover tunnels. To minimise costs, the strength of the soil needs to be determined in the best possible way. The drained strength of clay...... expressed by c and ϕ is often estimated as c 10% = 10%・cu, and found by estimations based on the soil describtion, respectively. However, due to possible slicken slides and tension cracks, c = 0 is used on the back side of the sheet pile wall. This reduces the strength significantly. A parametric study is...
3D finite element analysis on pile-soil interaction of passive pile group
Institute of Scientific and Technical Information of China (English)
ZHAO Ming-hua; LIU Dun-ping; ZHANG Ling; JIANG Chong
2008-01-01
The interaction between pile and soft soil of the passive pile group subjected to soil movement was analyzed with three-dimensional finite element model by using ANSYS software. The soil was assumed to be elastic-plastic complying with the Drucker-Prager yield criterion in the analysis. The large displacement of soil was considered and contact elements were used to evaluate the interaction between pile and soil. The influences of soil depth of layer and number of piles on the lateral pressure of the pile were investigated, and the lateral pressure distributions on the (2×1) pile group and on the (2×2) pile group were compared. The results show that the adjacent surcharge may result in significant lateral movement of the soft soil and cousiderable pressure on the pile. The pressure acting on the row near the surcharge is higher than that on the other row, due to the "barrier" and arching effects in pile groups. The passive load and its distribution should be taken into account in the design of the passive piles.
Institute of Scientific and Technical Information of China (English)
ZHOU Hongbo; CHEN Zhuchang
2007-01-01
Based on the comparative analysis of end effect on skin friction of displacement-pile (driven pile),the end effect on skin friction of bored pile is studied.The end effect on skin friction between driven pile and bored pile is different and the end effect on skin friction of bored pile is reduce of skin friction in the soil layer adjacent to the pile end.The degradation degree of skin friction is deduced with the increase of the distance from pile end.The concept of additional mud cake formed by the effect of cushion at the bottom of borehole during pouring concrete is introduced to explain the mechanism of end effect on skin friction of the bored pile.The test results of post-grouting piles indicate that the post-grouting technique is an effective way to improve the end effect on skin friction of bored pile.
Energy Technology Data Exchange (ETDEWEB)
Furet, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1962-07-01
We have been led to study the problem of safety in atomic pile control as a result of our participation on the one hand in the planning of C.E.A. atomic piles, and on the other hand in the pile safety sub omission considering atomic pile safety of operational or planned C.E.A. piles. We have thus had to consider the wishes occurring in piles during their operation and also their behaviour in the dynamic state The present work deals mainly with the importance of intrinsic safety devices, with the influence of reactivity variations on the power fluctuations during accidental operation, and with the development of robust and reliable safety appliances. The starting p accident has been especially studied both for low-flux piles where a compromise is necessary between the response time of the safety appliances and the statistical fluctuations and for high lux piles where xenon poisoning has an effect on the lower limit of the velocity of reactivity liberation. The desirability has been stressed of automation as a safety factor in atomic pile control. The details required for an understanding of the diagrams of the apparatus are given. (author) [French] Nous avons aborde le probleme de la securite dans le controle des piles atomiques a la suite de notre participation d'une part aux avant rojets de piles atomiques du CE.A. et d'autre part a l'examen au sein de la sous ommission de surete des piles, de la securite des piles du CE.A. en fonctionnement ou en projet. Nous avons ete amenes a nous interesser alors aux risques encourus par les piles pendant leur fonctionnement et par la meme a leur comportement en regime dynamique. Ce travail traite principalement de l'importance des securites intrinseques, de l'influence des variations de reactivite sur les evolutions de puissance en regime d'accident et du developpement d'appareillages de securite robustes et de fonctionnement tres sur. L'accident de demarrage a ete particulierement
Test Setup for Axially Loaded Piles in Sand
DEFF Research Database (Denmark)
Thomassen, Kristina
The test setup for testing axially static and cyclic loaded piles in sand is described in the following. The purpose for the tests is to examine the tensile capacity of axially loaded piles in dense fully saturated sand. The pile dimensions are chosen to resemble full scale dimension of piles used...
Numerical Analysis of Piles in Layered Soils: A Parametric Study
Directory of Open Access Journals (Sweden)
Ravi Kumar Reddy C
2015-04-01
Full Text Available In this paper, numerical analysis of a pile-soil interaction problem is presented considering the parameters influencing the axial load-deformation behavior of the pile embedded in a layered soil medium. The analysis is demonstrated with parametric solutions of a pile with underlain model soil strata under the axial force. An attempt is made to ascertain the extent of influence of elastic properties of the pile, geometry of the pile, end conditions of the pile and the elastic properties of the underlain soil strata on the response of the piles under axial loads lying in a model soil layers in terms of the settlement of the pile and the internal deformation of the pile. The study revealed that the increase in modulus of elasticity of pile improves the settlement resistance of the pile, increase in the ratio of cross sectional dimensions causes decrease in the top deformations of the pile, the settlement of the pile reduced to a great extent when the cross section of the pile adopted is non circular instead of circular and increase in the elastic modulii of top and bottom layers of soil has decreased the settlement of the pile to a great extent, but elastic modulus of soil layers other than top and bottom has got negligible influence on the settlement of the pile.
Mechanical mechanism analysis of tension type anchor based on shear displacement method
Institute of Scientific and Technical Information of China (English)
XIAO Shu-jun; CHEN Chang-fu
2008-01-01
Based on the fact that the shear stress along anchorage segment is neither linearly nor uniformly distributed, the load transfer mechanism of the tension type anchor was studied and the mechanical characteristic of anchorage segment was analyzed. Shear stress-strain relationship of soil surrounding anchorage body was simplified into three-folding-lines model consisting of elastic phase, elasto-plastic phase and residual phase considering its softening eharaeteristic. Meanwhile, shear displacement method that has been extensively used in the analysis of pile foundation was introduced. Based on elasto-plastic theory, the distributions of displacement, shear stress and axial force along the anchorage segment of tension type anchor were obtained, and the formula for calculating the elastic limit load was also developed accordingly. Finally, an example was given to discuss the variation of stress and displacement in the anchorage segment with the loads exerted on the anchor, and a program was worked out to calculate the anchor maximum bearing capacity. The influence of some parameters on the anchor bearing capacity was discussed, and effective anchorage length was obtained simultaneously. The results show that the shear stress first increases and then decreases and finally trends to theresidual strength with increase of distance from bottom of the anchorage body, the displacement increases all the time with theincrease of distance from bottom of the anchorage body, and the increase of velocity gradually becomes greater.
Permanent ground anchors: Nicholson design criteria
Nicholson, P. J.; Uranowski, D. D.; Wycliffe-Jones, P. T.
1982-09-01
The methods used by Nicholson Construction Company in the design of permanent ground anchors specifically as related to retaining walls are discussed. Basic soil parameters, design concepts, drilling and grouting methods for ground anchors are discussed. Particular emphasis is placed on anchors founded in soil rather than rock formations. Also, soil properties necessary for the proper design of anchored retaining walls are detailed. The second chapter of the report is devoted to a general discussion of retaining wall and anchor design. In addition, a design example of an anchored retaining wall is presented in a step by step manner.
INTERACTION BETWEEN LONG PILES AND THE SOIL BODY AS PART OF THE SLAB-PILE FOUNDATION
Ter-Martirosyan ZavenGrigorevich; Trinh Tuan Viet
2012-01-01
The paper provides a definition of and a solution to the problems of interaction between long piles and the soil body as part of the slab-pile foundation with the due account for the interval between the piles, the length of piles and their correlations, as well as the nonlinear properties of soil identified by analytical and numerical methods through the application of Plaxis-2d software. It is proven that the above properties produce a substantial impact onto the stress-strain state of s...
Modelling the dynamic pile-soil-pile interaction in a multi-layered half-space
Hamad, Waleed; Ntotsios, Evangelos; Hunt, Hugh; Hussein, M.F.M.; Thompson, D. J.; Talbot, James
2015-01-01
Within the context of railway ground-borne vibration, the dynamic pile-soil-pile interaction remains an area that has not been sufficiently investigated. Whilest a number of researchers have scrutinised the vibration response of piled-foundations, their approaches exhibit a compromise between computation time and solution accuracy. In this paper, two models of piled-foundations in a multi-layered half-space are presented; one is an efficient semi-analytical model and another is a fully-couple...
Local Scour Around Piles Under Wave Action
Institute of Scientific and Technical Information of China (English)
陈国平; 左其华; 黄海龙
2004-01-01
The model tests are performed with regular waves, and the effect of wave height, wave period, water depth, scdiment size and pile diameter is evaluated. The shape and size of local scour around piles are studied. There are three typical scour patterns due to wave action. It is found that a relationship exists between the erosion depth and the wave number. An empirical formula of the maximum local scour is thus derived.
Seismic soil pile interaction:experimental evidence
Moccia, Flaviana
2009-01-01
The comprehension of the real behaviour of pile foundations under earthquake loading is very important, since it can significantly affect the performance of the superstructure. As a matter of fact the experience of recent earthquake has confirmed that piles can suffer extreme damage and failure under earthquake loading. The case histories from Kobe earthquake (1995) indicate that not only the inertial actions but also the kinematic ones, due to ground movements, which was overlooked in design...
Pulse pile-up. I: Short pulses
International Nuclear Information System (INIS)
The search for rare large pulses against an intense background of smaller ones involves consideration of pulse pile-up. Approximate methods are presented, based on ruin theory, by which the probability of such pile-up may be estimated for pulses of arbitrary form and of arbitrary pulse-height distribution. These methods are checked against cases for which exact solutions are available. The present paper is concerned chiefly with short pulses of finite total duration. (Author) (5 refs., 24 figs.)
Physical and numerical modelling of earth pressure on anchored sheet pile walls in sand
DEFF Research Database (Denmark)
Krogsbøll, Anette Susanne; Fuglsang, Leif D
The influence of wall flexibility on earth pressure, bending moments and failure modes is studied. Numerical models are compared to results from model tests carried out in a geotechnical centrifuge. The back-fill is dry sand and failure is introduced by allowing the wall to rotate around the anch...
Physical and numerical modelling of earth pressure on anchored sheet pile walls in sand
DEFF Research Database (Denmark)
Krogsbøll, Anette Susanne; Fuglsang, Leif D
2006-01-01
The influence of wall flexibility on earth pressure, bending moments and failure modes is studied. Numerical models are compared to results from model tests carried out in a geotechnical centrifuge. The back-fill is dry sand and failure is introduced by allowing the wall to rotate around the anch...
Grouting of uranium mill tailings piles
International Nuclear Information System (INIS)
A program of remedial action was initiated for a number of inactive uranium mill tailings piles. These piles result from mining and processing of uranium ores to meet the nation's defense and nuclear power needs and represent a potential hazard to health and the environment. Possible remedial actions include the application of covers to reduce radon emissions and airborne transport of the tailings, liners to prevent groundwater contamination by leachates from the piles, physical or chemical stabilization of the tailings, or moving the piles to remote locations. Conventional installation of liners would require excavation of the piles to emplace the liner; however, utilization of grouting techniques, such as those used in civil engineering to stabilize soils, might be a potential method of producing a liner without excavation. Laboratory studies on groutability of uranium mill tailings were conducted using samples from three abandoned piles and employing a number of particulate and chemical grouts. These studies indicate that it is possible to alter the permeability of the tailings from ambient values of 10-3 cm/s to values approaching 10-7 cm/s using silicate grouts and to 10-8 cm/s using acrylamide and acrylate grouts. An evaluation of grouting techniques, equipment required, and costs associated with grouting were also conducted and are presented. 10 references, 1 table
Pile foundation of nuclear power plant structures
International Nuclear Information System (INIS)
The subject of pile foundation used for nuclear power plant structures, considering the experience gained by the designers of the Angra Nuclear Power Plant, Units 2 and 3 in Brazil is dealt with. The general concept of the pile foundations, including types and execution of the piles, is described briefly. Then the two basic models, i.e. the static model and the dynamic one, used in the design are shown, and the pertinent design assumptions as related to the Angra project are mentioned. The criteria which established the loading capacity of the piles are discussed and the geological conditions of the Angra site are also explained briefly, justifying the reasons why pile foundations are necessary in this project. After that, the design procedures and particularly the tools - i.e. the computer programs - are described. It is noted that the relatively simple but always time consuming job of loading determination calculations can be computerized too, as it was done on this project through the computer program SEASA. The interesting aspects of soil/structure interaction, applicable to static models, are covered in detail, showing the theoretical base wich was used in the program PILMAT. Then the advantage resulting from computerizing of the job of pile reinforcement design are mentioned, describing briefly the jobs done by the two special programs PILDES and PILTAB. The point is stressed that the effort computerizing the structural design of this project was not so much due to the required accuracy of the calculations, but mainly due to the need to save on the design time, as to allow to perform the design task within the relatively tight time schedule. A conclusion can be drawn that design of pile foundations for nuclear power plant structures is a more complex task than the design of bearing type of foundation for the same structures, but that the task can be always made easier when the design process can be computerized. (Author)
The Effect of the Propeller Jet on Pile Groups
Institute of Scientific and Technical Information of China (English)
Kubilay Cihan
2014-01-01
The objective of this study is to determine the effect of jet propeller on the damage of berthing structures combined of armoured slope with pile groups. For this purpose, scour measurements were performed for four types berthing structures, which were armoured slope with tandem arrangements of piles for two and three piles and with side by side arrangements of piles for two and three piles. The effect of gap between piles on damage was investigated. The damage level induced by propeller jet between piles was determined. The gaps were 1, 2, 3, and 4 times the pile diameter. Three different values of Rpm (690, 820, and 950) were chosen for the tests. The diameter of circular piles is 40 mm. The slope ratio was 1/3 and the diameter of propeller was 10 cm.
Seismic behavior analysis of piled drums
International Nuclear Information System (INIS)
In general, low level radioactive waste is packed in drums and stored in a warehouse being piled vertically, or laid horizontally. To observe the behavior of piled drums during an earthquake, an experimental study was reported. The experimental study is limited by the vibrating platform capacity. To carry out these tests up to the supporting limit is not recommended, in view of the vibrating platform curing as well as the operators' security. It is very useful to develop the analytical method for simulating the behavior of the drums. In this report, a computer program of piled drum's dynamic motion is shown, and the analytical result is referred to the experimental result. From the result of experiment on piled drums, the sliding effect has been found to be very important for the stability of drum, and the rocking motion observed, showing a little acceleration is less than the static estimated value. Behavior of piled drums is a complex phenomena comprising of sliding, rocking and jumping
Anchoring in numeric judgments of visual stimuli
Directory of Open Access Journals (Sweden)
Linda eLangeborg
2016-02-01
Full Text Available This article investigates effects of anchoring in age estimation and estimation of quantities, two tasks which to different extents are based on visual stimuli. The results are compared to anchoring in answers to classic general knowledge questions that rely on semantic knowledge. Cognitive load was manipulated to explore possible differences between domains. Effects of source credibility, manipulated by differing instructions regarding the selection of anchor values (no information regarding anchor selection, information that the anchors are randomly generated or information that the anchors are answers from an expert on anchoring were also investigated. Effects of anchoring were large for all types of judgments but were not affected by cognitive load or by source credibility in either one of the researched domains. A main effect of cognitive load on quantity estimations and main effects of source credibility in the two visually based domains indicate that the manipulations were efficient. Implications for theoretical explanations of anchoring are discussed. In particular, because anchoring did not interact with source credibility or cognitive load, the results imply that the process behind anchoring in visual tasks is predominantly automatic and unconscious.
Inconspicuous anchoring effects generated by false information
Institute of Scientific and Technical Information of China (English)
Chen Qu; Jun Wang; Yuejia Luo
2008-01-01
The impact of false information on numerical judgments was examined on young normal subjects by an event-related potential (ERP) experiment. To imitate the judgments in real world, we ensured the subjects acknowledged of the target task. The behavioral results found that both uncertain information and false information assimilated the final estimates: higher after higher anchors and lower after lower anchors; and false information caused a weaker anchoring bias than uncertain information. ERP results provided further electrophysiological evidence for the mechanism of anchoring. In the early phrase, it was an accessibility-dominated process in which two kinds of anchors elicited an N300 component related to the accessibility of anchors propositions. The knowledge relevant to targets joined the process in the late phrase, which caused a larger amplitude of late positive component (LPC) for implausible lower anchors than that for plausible higher anchors. Source analysis showed that medial frontal gyrus, whose activity was suggested to signal the need of adjustment, was more reliable to explain the LPC elicited by implausible lower anchors. Therefore, we suggest that accessibility is facilitated when the external anchor is consistent with the world knowledge, and adjustment is initiated when the external anchor is inconsistent.
Anchoring in Numeric Judgments of Visual Stimuli.
Langeborg, Linda; Eriksson, Mårten
2016-01-01
This article investigates effects of anchoring in age estimation and estimation of quantities, two tasks which to different extents are based on visual stimuli. The results are compared to anchoring in answers to classic general knowledge questions that rely on semantic knowledge. Cognitive load was manipulated to explore possible differences between domains. Effects of source credibility, manipulated by differing instructions regarding the selection of anchor values (no information regarding anchor selection, information that the anchors are randomly generated or information that the anchors are answers from an expert) on anchoring were also investigated. Effects of anchoring were large for all types of judgments but were not affected by cognitive load or by source credibility in either one of the researched domains. A main effect of cognitive load on quantity estimations and main effects of source credibility in the two visually based domains indicate that the manipulations were efficient. Implications for theoretical explanations of anchoring are discussed. In particular, because anchoring did not interact with cognitive load, the results imply that the process behind anchoring in visual tasks is predominantly automatic and unconscious. PMID:26941684
Anchors and their use in offshore petroleum operations
Energy Technology Data Exchange (ETDEWEB)
1984-01-01
Holding a ship or vessel in a fixed position over specific spots is essential in drilling subsea wells. Conventional anchors and holding systems have thus been transformed into permanent mooring points capable of withstanding enormous stresses. This book specifies the parameters directly governing behavior of these new anchors, studies the mechanisms involved in anchor/seabed interaction and interprets these in the context of soil mechanics, and draws practical conclusions in the form of methods for predicting holding capacity in different types of subsea soils. Contents are: history of anchors; high-capacity anchoring systems; kinetics of anchors; holding power of anchors; anchoring site survey; choice of an anchor; and anchoring tests.
Transient response of piles-bridge under horizontal excitation
Institute of Scientific and Technical Information of China (English)
朱斌; 陈仁朋; 陈云敏
2003-01-01
Moving ships and other objects drifting on water often impact a bridge's pile foundations. The mechanical model of the piles-bridge structure under horizontal forcing was established, and a time-domain approach based on Finite-difference Method was developed for analyzing the dynamic response of the piles-bridge structure. For a single pile, good agreement between two computed results validated the present approach. The slenderness ratio of the pile, the pile-soil stiffness ratio and the type of the structure influence the dynamic response of the piles-bridge structure. The computed results showed that the stiffness of the structure determines the dynamic response of the piles-bridge structure under horizontal forcing.
Transient response of piles-bridge under horizontal excitation
Institute of Scientific and Technical Information of China (English)
朱斌; 陈仁朋; 陈云敏
2003-01-01
Moving ships and other objects drifting on water often impact a bridge' s pile foundations. The mechanical model of the piles-bridge structure under horizontal forcing was established, and a time-domain approach based on Finite-difference Method was developed for analyzing the dynamic response of the piles-bridge structure. For a single pile, good agreement between two computed results validated the present approach.The slenderness ratio of the pile, the pile-soil stiffness ratio and the type of the structure influence the dynamic response of the piles-bridge structure. The computed results showed that the stiffness of the structure determines the dynamic response of the piles-bridge structure under horizontal forcing.
The Tensile Capacity Of Bored Piles In Frictional Soils
DEFF Research Database (Denmark)
Krabbenhøft, Sven; Andersen, Allan; Damkilde, Lars
2008-01-01
Three series of 10 piles each were installed in two different locations. The length of the piles varied from 2 to 6 m and the diameters were 14 and 25 cm. The piles were constructed above the groundwater table using continuous flight augers and the concrete was placed by gravity free fall. The pi...... piles were tested to failure in axial uplift and the load-displacement relations were recorded....
THE KINEMATIC AND INERTIAL SOIL-PILE INTERACTIONS: CENTRIFUGE MODELLING
Chenaf, Nawel; CHAZELAS, Jean-Louis
2008-01-01
International audience Piles supporting superstructures undergo with the soil two interactions during an earthquake: the kinematic interaction and the inertial interaction. The kinematic soil-pile interaction is the pile loading by the soil displacement produced by the seismic waves propagating. Inertial superstructure-pile-soil interaction results from forces due to the superstructure actuation by the kinematic interaction. These two interactions are superimposed in seismic events and the...
40 CFR 264.554 - Staging piles.
2010-07-01
... Professional Engineer for technical data, such as design drawings and specifications, and engineering studies... operation; (ii) Volumes of wastes you intend to store in the pile; (iii) Physical and chemical characteristics of the wastes to be stored in the unit; (iv) Potential for releases from the unit;...
Global and local scour at pile groups
DEFF Research Database (Denmark)
Sumer, B. Mutlu; Bundgaard, Klavs; Fredsøe, Jørgen
This paper presents the results of an experimental investigation on scour around pile groups with different configurations exposed to steady current. Two kinds of tests were carried out: (1) Rigid-bed tests, and (2) Actual scour tests. In the former tests, the mean and turbulence properties of th...
Global and local scour at pile groups
DEFF Research Database (Denmark)
Sumer, B. Mutlu; Bundgaard, Klavs; Fredsøe, Jørgen
2005-01-01
This paper presents the results of an experimental investigation on scour around pile groups with different configurations exposed to steady current. Two kinds of tests were carried out: rigid-bed tests and actual scour tests. In these, the mean and turbulence properties of the flow were measured...
Underwater noise generated by offshore pile driving
Tsouvalas, A.
2015-01-01
Anthropogenic noise emission in the marine environment has always been an environmental issue of serious concern. In particular, the noise generated during the installation of foundation piles is considered to be one of the most significant sources of underwater noise pollution. This is mainly attri
Modelling Pile Installation Effects: A Numerical Approach
Engin, H.K.
2013-01-01
One of the most traditional methods for supporting structures resting on soft soils is the use of piles. They generally work by transferring the loads to deeper soil layers, which can provide sufficient bearing capacity when mobilised. This type of foundations has been commonly used throughout the w
Amalia, Nadya; Asri, Asifa; Rokhmat, Mamat; Sutisna; Abdullah, Mikrajuddin
2015-01-01
Using a model for concrete piles driven into clays, we compared penetration depths between uncoated piles and piles coated with titanium dioxide (TiO2) nanoparticles. The behavior of surfaces coated with TiO2 changes to superhydrophilic, enabling water molecules to penetrate inside the clay pores. The attraction suppresses or reduces the compression of water inside the clay pores. The absence of bulk pressure from water causes the pile not to bounce (backward movement after striking). Contrar...
Pile – Soil Interaction during Vibratory Sheet Pile Driving : a Full Scale Field Study
Guillement, Claire
2013-01-01
Urban construction sites require strict control of their environmental impact, which, for vibratory sheet pile driving, can include damage to nearby structures due to ground vibrations. However, the lack of knowledge concerning the generation of soil vibrations makes the prediction of ground vibration levels difficult. This MSc. thesis in particular, focuses on a crucial link in the vibration transfer chain: the sheet pile – soil interface, which is also one of the least documented. The aim o...
Shifting Nominal Anchors: The Experience of Mexico
Leonardo Leiderman; Nissan Liviatan; Alfredo Thorne
1995-01-01
In the mid-1980’s Mexico successfully brought down its high rate of inflation by using the exchange rate as nominal anchor in combination with strict fiscal discipline, tight monetary policy, and incomes policy. This paper discusses the role of exchange rate policy as nominal anchor in Mexico and develops the inflation target as the monetary framework for anchoring prices. It also describes how Mexico is applying this frame work while shifting to a more flexible exchange regime and discusses ...
Capital Asset Pricing Model Adjusted for Anchoring
Hammad, Siddiqi
2015-01-01
I show that adjusting CAPM for anchoring provides a unified explanation for the size, value, and momentum effects. Anchoring adjusted CAPM (ACAPM) predicts that stock splits are associated with positive abnormal returns and an increase in return volatility, whereas the reverse stock-splits are associated with negative abnormal returns and a fall in return volatility. Existing empirical evidence strongly supports these predictions. Anchoring has the effect of pushing up the equity premium, a ...
Genetic Effects of Pile Radiations in Rice
International Nuclear Information System (INIS)
In attempts to utilize radiation-induced mutations for rice breeding, it is of primary interest to obtain the fundamental data of the biological effects of pile radiations. Although considerable variation of radiosensitivity was found among rice varieties, Japanese rice was comparatively more susceptible to pile radiations than foreign varieties, and tetraploids were less susceptible as compared with the diploid varieties after irradiation. From die observation of the radiation injury of F1, hybrids it was concluded that, in addition to the contribution of a gene or a gene system, the cytoplasm was related to the intervarietal difference of radiosensitivity. Sterility was more easily induced by pile radiations than X-irradiation. In the X-ray series, chlorophyll mutations on the X1-ear basis reached a maximum frequency at middle doses and decreased at higher doses. In the pile radiation series the frequency increased with increasing doses. The cause of differences of these two series seemed to be a difference of the mean size of mutated sectors between both the radiations. The increment of induced variation on quantitative characters occurred in plus and minus direction with similar frequencies after the treatment of pile radiations. However, the heritable variations did not increase in accordance with neutron flux. The amount of induced variation was more in the progenies of partially sterile X1 ear and less in those which segregated chlorophyll mutants in X2 generation. It was calculated that 1 r of X- and gamma-rays was equivalent to 1-2 x 109 thermal neutrons per cm2 for induction of chlorophyll mutations and of variation on quantitative characters. (author)
Seismic Response Analysis of Portal Water Injection Sheet Pile
Institute of Scientific and Technical Information of China (English)
WANG Yuanbin; GUO Haiyan; ZHANG Chunhui
2007-01-01
To further the study on the newly developed portal water injection sheet pile under static loads, in this paper, by adopting the nonlinear calculation module of FEM software ANSYS, a model for the interaction between the soil and the sheet piles is set up,and the seismic response analysis for this type of space-retaining structure is performed. The effects of the embedded depth and the distance between the front pile and the back pile on the dynamic characteristics of the portal water injection sheet pile are studied.
The Settlement Behavior of Piled Raft Interaction in Undrained Soil
DEFF Research Database (Denmark)
Ghalesari, Abbasali Taghavi; Barari, Amin; Amini, Pedram Fardad;
2013-01-01
, the behavior of a piled raft on undrained soil is studied based on a series of parametric studies on the average and differential settlement of piled raft using three-dimensional finite element analysis. The settlement behavior is found to be dependent on the number of piles and raft thickness.......Offshore piled raft foundations are one of the most commonly used foundations in offshore structures. When a raft foundation alone does not satisfy the design requirements, the addition of piles may improve both the ultimate load capacity and the settlement performance of the raft. In this paper...
The Strength of Rubble Pile Asteroids
Scheeres, D. J.; Sanchez, P.
2012-12-01
The rubble pile hypothesis for small asteroids in the Near Earth and Main Belt populations have been driven by several factors, including the observed high porosity of those bodies whose mass have been measured, the evident limitation on spin rate of asteroids larger than ~500 meters, and direct observation of the surface morphology of these bodies. Given these observations, it has been presumed that small asteroids should evolve as if they were cohesionless collections of grains. Detailed geophysical analysis of these bodies by Holsapple (Icarus 2010) show that cohesionless bodies will evolve under the addition of angular momentum by the YORP effect into more distended and, paradoxically, more slowly rotating bodies. Additional analysis in Holsapple (Icarus 2007) has shown that cohesional strength within a rubble pile could strengthen a collection of grains to the point where they could sustain rapid rotation. In our current talk we use the above as a starting point and incorporate new observations of the asteroid morphology driven by recent analysis of asteroid Itokawa by the Hayabusa science team and research on the mechanics of grains in the space environment (Scheeres et al. 2010). Analysis of images of Itokawa determined a measured size distribution of 1/d^3 for larger grains on asteroid Itokawa (Michikami et al., Earth Planets Space, 60, 13-20, 2008). Analysis of the sample shows the presence of micron sized dust on that asteroid's surface (Tsuchiyama et al., Science 333, 1125, 2011). Combining these observations provides a global indication of grain distribution within rubble piles. Even assuming a less steep distribution of 1/d^2 for dust grains smaller than 1 mm in size, the interior of Itokawa should still be dominated by the finest dust grains, with the mean grain size equal to ~ twice the smallest grain in the distribution. One implication of this result is that fines are present on the surface of the rubble pile Itokawa and thus should be distributed
Numerical analysis of kinematic soil—pile interaction
Castelli, Francesco; Maugeri, Michele; Mylonakis, George
2008-07-01
In the present study, the response of singles pile to kinematic seismic loading is investigated using the computer program SAP2000@. The objectives of the study are: (1) to develop a numerical model that can realistically simulate kinematic soil-structure interaction for piles accounting for discontinuity conditions at the pile-soil interface, energy dissipation and wave propagation; (2) to use the model for evaluating kinematic interaction effects on pile response as function of input ground motion; and (3) to present a case study in which theoretical predictions are compared with results obtained from other formulations. To evaluate the effects of kinematic loading, the responses of both the free-field soil (with no piles) and the pile were compared. Time history and static pushover analyses were conducted to estimate the displacement and kinematic pile bending under seismic loadings.
Institute of Scientific and Technical Information of China (English)
顾寄平
2000-01-01
It introduces the calculation principle for the structures of three 50, 000 dwtcontainer terminals of Yantian Port 2nd-phase Project, types of foundation piles and the structural types, piling control standard, as well as the construction machinery and construction method for embedded piles, anchor piles and embedded-anchor piles. It also gives an introduction to the actural bearing capacity testing by combining high-strain dynamic test with static load test.%介绍盐田港二期3个5万吨级集装箱码头结构的计算原则，基桩类型及其结构型式，沉桩控制标准及嵌岩桩、锚定桩、锚定嵌桩的施工机具和施工方法，还介绍了采用高应变动力试验与静载试验相结合的方法验证工程桩实际承载力的情况。
Method of fabrication of anchored nanostructure materials
Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei
2013-11-26
Methods for fabricating anchored nanostructure materials are described. The methods include heating a nano-catalyst under a protective atmosphere to a temperature ranging from about 450.degree. C. to about 1500.degree. C. and contacting the heated nano-catalysts with an organic vapor to affix carbon nanostructures to the nano-catalysts and form the anchored nanostructure material.
Suction anchors for floating production systems
Energy Technology Data Exchange (ETDEWEB)
Tjelta, T.I.; Rusas, P. [Statoil a.s. (Norway); Edvardsen, G. [HEX a.s. (Norway)
1996-12-31
Since the suction anchor is a recent development in its current use, this work provides a brief historical background. It is shown that the suction anchor throughout evolution today is a competitive foundation solution for many applications. Examples from these categories are included in this paper. Also several installation methods are discussed. 3 refs., 7 figs., 2 tabs.
Li, Qiang; Shi, Qian; Wang, Kuihua
2010-06-01
In this study, a simplified computational model of pile vertical vibration was developed. The model was based on the inhomogeneous radial disturbed zone of soil in the vicinity of a pile disturbed by pile driving. The model contained two regions: the disturbed zone, which was located in the immediate vicinity of the pile, and the undisturbed region, external to the disturbed zone. In the model, excess pore pressure in the disturbed zone caused by pile driving was assumed to follow a logarithmic distribution. The relationships of stress and strain in the disturbed zone were based on the principle of effective stress under plain strain conditions. The external zone was governed by the poroelastic theory proposed by Biot. With the use of a variable separation method, an analytical solution in the frequency domain was obtained. Furthermore, a semi-analytical solution was attained by employing a numerical convolution method. Numerical results from the frequency and time domain indicated that the equivalent radius of the disturbed zone and the ratio of excess pore pressure had a significant effect on pile dynamic response. However, actual interactions between pile and soil will be weaker due to the presence of the radial disturbed zone, which is caused by pile driving. Consequently, the ideal undisturbed model overestimates the interaction between pile and soil; however, the proposed model reflects the interaction of pile and soil better than the perfect contact model. Numerical results indicate that the model can account for the time effect of pile dynamic tests.
Institute of Scientific and Technical Information of China (English)
朱峰; 徐卫亚; 王环玲
2014-01-01
The pile-soil interaction under wave loads is an extremely complex and difficult issue in engineering. In this study, a physical model test is designed based on the principle of the gravity similarity to obtain time histories of wave forces of unsteady regular waves, and to measure the magnitude and the distribution of wave forces acting on the piles. A numerical model and relevant numerical methods for the pile-soil contact surface are adopted based on the principles of elastic dynamics. For a practical project, the time histories of wave forces on the piles are obtained through physical model tests. The deformations of the piles in the pile-soil interactions and the distribution of the bending moment on the piles are studied. It is shown that, with the increase of the period of wave pressures, the absolute value of the horizontal displacement of the piles increases, the embedment depth of the piles increases, and the scope of influence of soils increases. The change of the bending moment on the piles is consistent with that of its theoretical results, and the proposed numerical method can very well simulate the properties of the piles.
Stratified chaos in a sand pile formation
Poortinga, Ate; Ritsema, Coen J
2014-01-01
Sand pile formation is often used to describe stratified chaos in dynamic systems due to self-emergent and scale invariant behaviour. Cellular automata (Bak-Tang-Wiesenfeld model) are often used to describe chaotic behaviour, as simulating physical interactions between individual particles is computationally demanding. In this study, we use a state-of-the-art parallel implementation of the discrete element method on the graphical processing unit to simulate sand pile formation. Interactions between individual grains were simulated using a contact model in an Euler integration scheme. Results show non-linear self-emergent behaviour which is in good agreement with experimental results, theoretical work and self organized criticality (SOC) approaches. Moreover, it was found that the fully deterministic model, where the position and forces on every individual particle can be determined every iteration has a brown noise signal in the x and y direction, where the signal is the z direction is closer to a white noise...
Introduction to Single Piles under Lateral Loading
DEFF Research Database (Denmark)
Augustesen, Anders; Ibsen, Lars Bo
.2). The description is based on results of laboratory tests, full-scale field tests as well as numerical investigations presented in literature. Second, general methods that attempt to model lateral pile response are discussed in section 1.4. Third, focus is paid to a widely used method for prediction of...... Committee for Standardization), DNV (2004b) (Det Norske Veritas), CEN (2004) (European Committee for Standardization), ISO (2001) (International Organization for Standardization) and API (1993) (American Petroleum Institute)....
Soil Structure Interaction in Energy Piles
Chen, Diming
2016-01-01
This study focuses on developing an improved thermo-mechanical soil-structure interaction (i.e., load transfer) analysis to assess the axial strains, stresses, and displacements during thermo-mechanical loading of energy piles in different soils having different end restraint boundary conditions. This study builds on established analyses by (i) incorporating an algorithm to identify the location of the point of zero displacement (i.e., the null point) during changes in temperature, (ii) addin...
Underwater noise generated by offshore pile driving
Tsouvalas, A.
2015-01-01
Anthropogenic noise emission in the marine environment has always been an environmental issue of serious concern. In particular, the noise generated during the installation of foundation piles is considered to be one of the most significant sources of underwater noise pollution. This is mainly attributed to the recent developments in the offshore wind industry. To meet the increasing demand for energy from renewable resources, a large number of offshore wind farms are planned to be constructe...
CENTRIFUGAL VIBRATION TEST OF RC PILE FOUNDATION
Higuchi, Shunichi; Tsutsumiuchi, Takahiro; Otsuka, Rinna; Ito, Koji; Ejiri, Joji
It is necessary that nonlinear responses of structures are clarified by soil-structure interaction analysis for the purpose of evaluating the seismic performances of underground structure or foundation structure. In this research, centrifuge shake table tests of reinforced concrete pile foundation installed in the liquefied ground were conducted. Then, finite element analyses for the tests were conducted to confirm an applicability of the analytical method by comparing the experimental results and analytical results.
Energy piles: site investigation and analysis
Hemmingway, Phil; Long, Michael
2013-01-01
Despite an increasing worldwide use of geothermal energy foundations, there is a lack of published guidelines and results from thermal response testing of such installations. In this paper the results are presented from thermal response, thermal recovery and laboratory thermal testing performed at two sites in Ireland. Some practical issues concerned with the use of thermal response testing rigs, designed for use with deep boreholes, on relatively short piles are discussed and addressed. Give...
不同运动方向两桩间桩-土-桩相互作用%PILE-SOIL-PILE INTERACTION BETWEEN TWO PILES MOVING ALONG DIFFERENT DIRECTIONS
Institute of Scientific and Technical Information of China (English)
孔令刚; 樊继营; 陈仁朋; 陈云敏
2013-01-01
Both centrifuge modeling and numerical simulation are employed to investigate pile-soil-pile interaction between two adjacent piles with pile spacing of 3 times pile diameter moving in different directions. The influence of pile spacing,internal friction angle of sand,and different displacements of the leading and trailing piles on reduction factor are also analyzed based on numerical results. It is found that pile-soil-pile interaction is significant in two adjacent piles undergoing different movement directions. The reduction factor of the trail pile is not larger than that of the leading one in the investigated two cases. It is also found that reduction factors for the leading and trail piles almost linearly increase as pile spacing varies from 3 times pile diameter to 5 times and almost keep constant with internal friction angle. In addition,loading mode has certain effect on reduction factors of the two piles.%通过离心模型试验和数值模拟手段研究不同运动方向下桩间距为3倍桩径的两桩间相互作用规律，并分析桩间距、土体内摩擦角以及不同桩头位移对前、后桩折减系数的影响。通过分析表明，沿不同方向运动的两桩间存在明显的桩-土-桩相互作用，该相互作用效果与桩所在位置有明显关系，前桩的相互作用折减系数明显大于于后桩；当桩间距在3～5倍桩径范围内，前、后桩折减系数随桩间距近似线性变化；砂土内摩察角对折减系数的影响可以忽略。另外，不同加载方式对两桩的折减系数也有一定影响。
Reheating experiment in the 35-ton pile
International Nuclear Information System (INIS)
When the 35-ton pile was started up it was necessary for us, in order to study certain effects (xenon for example), to know the anti reactivity value of the rods as a function of their dimensions. We have made use of the possibility, in the reheating experiment, of raising the temperature of the graphite-uranium block by simple heating, in order to determine the anti reactivity curves of the rods, and from that the overall temperature coefficient. For the latter we have considered two solutions: first, one in which the average temperature of the pile is defined as our arithmetical mean of the different values given by the 28 thermocouples distributed throughout the pile; a second in which the temperature in likened to a poisoning and is balanced by the square of the flux. The way in which the measurements have been made is indicated, and the different instruments used are described. The method of reheating does not permit the separation of the temperature coefficients of uranium and of graphite. The precision obtained is only moderate, and suffers from the changes of various parameters necessary to other manipulations carried out simultaneously (life time modulators for example), and finally it is a function of the comparatively restricted time allowed. It is evident of course that more careful stabilisation at the different plateaux chosen would have necessitated long periods of reheating. (author)
Bearing Behaviors of Stiffened Deep Cement Mixed Pile
Institute of Scientific and Technical Information of China (English)
WU Mai; ZHAO Xin
2006-01-01
A series of investigations were conducted to study the bearing capacity and load transfer mechanism of stiffened deep cement mixed (SDCM) pile.Laboratory tests including six specimens were conducted to investigate the frictional resistance between the concrete core and the cementsoil.Two model piles and twenty-four full-scale piles were tested to examine the bearing behavior of single pile.Laboratory and model tests results indicate that the cohesive strength is large enough to ensure the interaction between core pile and the outer cement-soil.The full-scale test results show that the SDCM piles exhibit similar bearing behavior to bored and cast-in-place concrete piles.In general, with the rational composite structure the SDCM piles can transmit the applied load effectively, and due to the addition of the stiffer core, the SDCM piles possess high bearing capacity.Based on the findings of these experimental investigations and theoretical analysis, a practical design method is developed to predict the vertical bearing capacity of SDCM pile.
FORECASTING PILE SETTLEMENT ON CLAYSTONE USING NUMERICAL AND ANALYTICAL METHODS
Directory of Open Access Journals (Sweden)
Ponomarev Andrey Budimirovich
2016-06-01
Full Text Available In the article the problem of designing pile foundations on claystones is reviewed. The purpose of this paper is comparative analysis of the analytical and numerical methods for forecasting the settlement of piles on claystones. The following tasks were solved during the study: 1 The existing researches of pile settlement are analyzed; 2 The characteristics of experimental studies and the parameters for numerical modeling are presented, methods of field research of single piles’ operation are described; 3 Calculation of single pile settlement is performed using numerical methods in the software package Plaxis 2D and analytical method according to the requirements SP 24.13330.2011; 4 Experimental data is compared with the results of analytical and numerical calculations; 5 Basing on these results recommendations for forecasting pile settlement on claystone are presented. Much attention is paid to the calculation of pile settlement considering the impacted areas in ground space beside pile and the comparison with the results of field experiments. Basing on the obtained results, for the prediction of settlement of single pile on claystone the authors recommend using the analytical method considered in SP 24.13330.2011 with account for the impacted areas in ground space beside driven pile. In the case of forecasting the settlement of single pile on claystone by numerical methods in Plaxis 2D the authors recommend using the Hardening Soil model considering the impacted areas in ground space beside the driven pile. The analyses of the results and calculations are presented for examination and verification; therefore it is necessary to continue the research work of deep foundation at another experimental sites to improve the reliability of the calculation of pile foundation settlement. The work is of great interest for geotechnical engineers engaged in research, design and construction of pile foundations.
Response of shallow geothermal energy pile from laboratory model tests
Marto, A.; Amaludin, A.
2015-09-01
In shallow geothermal energy pile systems, the thermal loads from the pile, transferred and stored in the soil will cause thermally induced settlement. This factor must be considered in the geotechnical design process to avoid unexpected hazards. Series of laboratory model tests were carried out to study the behaviour of energy piles installed in kaolin soil, subjected to thermal loads and a combination of axial and thermal loads (henceforth known as thermo-axial loads). Six tests which included two thermal load tests (35°C and 40°C) and four thermo-axial load tests (100 N and 200 N, combined with 35°C and 40°C thermal loads) were conducted. To simulate the behaviour of geothermal energy piles during its operation, the thermo-axial tests were carried out by applying an axial load to the model pile head, and a subsequent application of thermal load. The model soil was compacted at 90% maximum dry density and had an undrained shear strength of 37 kPa, thus classified as having a firm soil consistency. The behaviour of model pile, having the ultimate load capacity of 460 N, was monitored using a linear variable displacement transducer, load cell and wire thermocouple, to measure the pile head settlement, applied axial load and model pile temperature. The acquired data from this study was used to define the thermo-axial response characteristics of the energy pile model. In this study, the limiting settlement was defined as 10% of the model pile diameter. For thermal load tests, higher thermal loads induced higher values of thermal settlement. At 40°C thermal load an irreversible settlement was observed after the heating and cooling cycle was applied to the model pile. Meanwhile, the pile response to thermo-axial loads were attributed to soil consistency and the magnitude of both the axial and thermal loads applied to the pile. The higher the thermoaxial loads, the higher the settlements occurred. A slight hazard on the model pile was detected, since the settlement
Institute of Scientific and Technical Information of China (English)
LIU Run; YAN Shu-wang; LI Zhi-hua
2009-01-01
Long steel piles with large diameters have been more widely used in the field of ocean engineering.Owing to the pile with a large diameter,soil plug development during pile driving has great influences on pile driveability and beating capacity.The response of soil plug developed inside the open-ended pipe pile during the dynamic condition of pile-driving is different from the response under the static condition of loading during service.This paper addresses the former aspect.A numerical procedure for soil plng effect prediction and pile driveability analysis is proposed and described.By taking into consideration of the pile dimension effect on side and tip resistance,this approach introduces a dimensional coefficient to the conventional static equilibrium equations for the plug differential unit and proposes an improved static equity method for the plug effect prediction.At the same time,this approach introduces a simplified model by use of one-dimensional stress wave equation to simulate the interaction between soft ping and pile inner wall.The proposed approach has been applied in practical engineering analyses.Results show that the calculated plug effect and pile driveability based on the proposed approach agree well with the observed data.
Impedance function of a group of vertical piles
International Nuclear Information System (INIS)
Impedance and transfer functions of a group of vertical piles located in any desired configuration in plan in a horizontally stratified soil layer are derived. Hysteretic and radiation damping are accounted for. The method separates the piles and the soil, introducing unknown interaction forces. The total flexibility matrix of the soil is constructed, superposing the (complex) flexibility coefficients caused by the interaction forces of a single pile only. The dependence of the impedance and transfer functions on the oscllating frequency for foundations with different numbers of piles is investigated. Pile-soil-pile interaction is shown to be very important for all modes of vibration. The procedure is used in the seismic analysis of a reactor building. (Author)
Settlement calculation for long-short composite piled raft foundation
Institute of Scientific and Technical Information of China (English)
ZHAO Ming-hua; ZHANG Ling; YANG Ming-hui
2006-01-01
The mechanism of long-short composite piled raft foundation was discussed. Assuming the relationship between shear stress and shear strain of the surrounding soil was elasto-plastic, shear displacement method was employed to establish the different explicit relational equations between the load and the displacement at the top of pile in either elastic or elasto-plastic period. Then Mylonakis & Gazetas model was introduced to simulate the interaction between two piles or between piles and soil. Considering the effect of cushion, the flexible coefficients of interaction were provided. With the addition of a relevant program, the settlement calculation for long-short composite piled raft foundation was developed which could be used to account for the interaction of piles,soil and cushion. Finally, the calculation method was used to analyze an engineering example. The calculated value of settlement is 10.2 mm, which is close to the observed value 8.8 mm.
Anchored nanostructure materials and method of fabrication
Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei
2012-11-27
Anchored nanostructure materials and methods for their fabrication are described. The anchored nanostructure materials may utilize nano-catalysts that include powder-based or solid-based support materials. The support material may comprise metal, such as NiAl, ceramic, a cermet, or silicon or other metalloid. Typically, nanoparticles are disposed adjacent a surface of the support material. Nanostructures may be formed as anchored to nanoparticles that are adjacent the surface of the support material by heating the nano-catalysts and then exposing the nano-catalysts to an organic vapor. The nanostructures are typically single wall or multi-wall carbon nanotubes.
In-Pile Thermal Conductivity Measurement Methods for Nuclear Fuels
Fox, Brandon S.
2010-01-01
Measuring nuclear fuel thermal conductivity in-pile can provide much needed data for understanding fuel performance during irradiation and yield thermophysical property data needed for simulation codes and fuel databases. The objective of this research is to develop and compare two in-pile thermal conductivity methods in a laboratory setting using surrogate fuel materials. A steady-state radial heat flow method was investigated to understand its viability as an in-pile steady-state thermal...
Influence of heave reducing piles on ground movements around excavations
McNamara, A M
2001-01-01
The research concerns the influence of piles, installed beneath deep excavations, as a means of reducing movements in the surrounding ground. The work focussed on the use of piles installed as a part of top down basement construction, a technique used in conjunction with deep excavations in urban areas. The investigations sought to explore the effectiveness of bored piles as a means of enhancing the stiffness of the soil beneath the excavation and so reducing the spread of movements to the su...
Foundation heat transfer analysis for buildings with thermal piles
International Nuclear Information System (INIS)
Highlights: • A numerical transient thermal model for thermo-active foundations is developed. • Thermal interactions between thermal piles and building foundations are evaluated. • A simplified analysis method of thermal interactions between thermal piles and building foundations is developed. - Abstract: Thermal piles or thermo-active foundations utilize heat exchangers embedded within foundation footings to heat and/or cool buildings. In this paper, the impact of thermal piles on building foundation heat transfer is investigated. In particular, a simplified analysis method is developed to estimate the annual ground-coupled foundation heat transfer when buildings are equipped with thermal piles. First, a numerical analysis of the thermal performance of thermo-active building foundations is developed and used to assess the interactions between thermal piles and slab-on-grade building foundations. The impact of various design parameters and operating conditions is evaluated including foundation pile depth, building slab width, foundation insulation configuration, and soil thermal properties. Based on the results of a series of parametric analyses, a simplified analysis method is presented to assess the impact of the thermal piles on the annual heat fluxes toward or from the building foundations. A comparative evaluation of the predictions of the simplified analysis method and those obtained from the detailed numerical analysis indicated good agreement with prediction accuracy lower than 5%. Moreover, it is found that thermal piles can affect annual building foundation heat loss/gain by up to 30% depending on foundation size and insulation level
Simulation of Pile-up in the ATLAS Experiment
Marshall, Z; The ATLAS collaboration
2014-01-01
The high luminosity of the LHC results in a significant background to interesting physics events known as pile-up. ATLAS has adopted two independent methods for modeling pile-up and its effect on analyses. The first is a bottom-up approach, using a detailed simulation of the detector to recreate each component of the pile-up background. The second uses specially recorded data events to emulate it. This article reports on the experience using both of these methods, including performance considerations, for simulating pile-up in ATLAS.
Critical sizes and flux distributions in the shut down pile
International Nuclear Information System (INIS)
An important part of the experiments carried out on the reactor G1 during a period of shut-down has consisted in determinations of critical sizes, and measurements of flux distribution by irradiations of detectors. This report deals with the following points: 1- Critical sizes of the flat pile, the long pile and the uranium-thorium pile. 2- Flux charts of the same piles, and study of an exponential experiment. 3- Determination of the slit effect. 4- Calculation of the anisotropy of the lattice. 5- Description of the experimental apparatus of the irradiation measurements. (author)
Soil-cement piles by drilling-mixing method
ZOTSENKO N.; VYNNYKOV YU.; ZOTSENKO V.
2015-01-01
Development of the drilling-mixing technology lead to the appearance of the soil-cement piles. It has all advantages of the drilling piles, but it eliminate the problem of the well walls stability. Drilling-mixing technology consist in, that machine with drilling-mixing head loosen soil; impregnated it by laitance; and mixed. Piles are perform from the excavation bottom until design depth. The movable soil-cement mixture feels wells during all the process. Pile has cylindrical form with set s...
Bearing Capacity of Mixed Pile with Stiffness Core
Institute of Scientific and Technical Information of China (English)
YUE Jianwei; JIANG Xinliang; LING Guangrong
2006-01-01
To study load transfer mechanism and bearing capacity of a mixed pile with stiffness core (MPSC), which is formed by inserting a precast reinforced concrete pile (PRCP), in-situ tests involving MPSCs with different lengths, diameters, water cement ratios and PRCPs, cement mixed piles, and drilling hole piles, were carried out.Limit bearing capacities, load-settlement curves and stress distribution of MPSCs and mixed piles were obtained.The load transfer between cement soil and PRCP was analyzed by finite element method (FEM).Test results and FEM analysis show that an MPSC has fully utilized the big friction from a cement mixed pile and the high compressive strength from a PRCP which transfers outer top load into the inner cement soil, and that inserting a PRCP into a mixed pile changes the stress distribution of a mixed pile and improves frictional resistance between a mixed pile and soil.The length and the section area on PRCP of an MPSC both have an optimum value.Adopting MPSC is effective in improving the bearing capacity of soft soil ground.
Threat from Rubble-Pile Asteroids
Schultz, P. H.
2015-12-01
While chondrites are the most common meteoroids to enter our atmosphere, they represent a small fraction of recovered falls. Most stony meteorites disrupt during entry, consumed by ablation or lost by weathering; in contrast, small iron meteorites (entry at altitude; (c) no accessory meteorite falls; (d) "explosion" (not low-speed compression) crater; (e) infrasound/seismic data indicating a high-speed entry/collision; and (f) petrologic evidence for shock deformation/melting in breccias indicative of speeds >4 km/s. Although a monolithic chondrite (~ 10 m across) might allow surviving entry, most objects of this size contain multiple flaws, ensuring atmospheric disruption. Hence, an alternative "needle model" was proposed wherein a small rubble-pile object gradually re-shaped itself during entry [Schultz, 2008], a process that minimizes drag, thermal signatures of entry, and catastrophic disruption. First proposed to account for smaller than expected craters on Venus [Schultz, 1992], such a process resembles subsequent Shoemaker-Levy entry models [Boslough and Crawford, 1997] that predicted much deeper entry than standard models. Laboratory experiments at the NASA Ames Vertical Gun Range simulated this process by breaking-up hypervelocity projectiles into a cloud of debris and tracking its path at near-full atmospheric pressure. The resulting cloud of fragments exhibited less deceleration than a solid sphere at the same speed. Moreover, shadowgraphs revealed constituent fragments "surfing" the pressure jump within the mach cone/column. Previous models proposed that crater-forming impacts must be >50-100 m in diameter in order to survive entry [Bland and Artemieva, 2004]. The "needle model" for the Carancas meteorite entry, however, raises questions about this lower limit for threats by rubble-pile asteroids, e.g., Itokawa. Consequently, we modeled the fate of a rubble-pile entering earth's atmosphere using GEODYN, an Eulerian code with adaptive mesh refinement
Engineering approach to modeling of piled systems
International Nuclear Information System (INIS)
Available methods of analysis of piled systems subjected to dynamic excitation invade areas of mathematics usually beyond the reach of a practising engineer. A simple technique that avoids that conflict is proposed, at least for preliminary studies, and its application, compared with other methods, is shown to be satisfactory. A corrective factor for parameters currently used to represent transmitting boundaries is derived for a finite strip that models an infinite layer. The influence of internal damping on the dynamic stiffness of the layer and on radiation damping is analysed. (Author)
International Nuclear Information System (INIS)
Accurate absolute measurements of v, the average number of neutrons per fission, have been made with the boron pile. The experimental method is described and results are presented of the v values obtained for the thermal-neutron-induced fission of U233, U235, Pu239 and Pu241, the spontaneous fission of Pu240 and Cf252, and the fast neutron-induced fission of U235 in the energy range 100 keV to 2.6 MeV. (author)
Anchoring Adjusted Capital Asset Pricing Model
Hammad, Siddiqi
2015-01-01
An anchoring adjusted Capital Asset Pricing Model (ACAPM) is developed in which the payoff volatilities of well-established stocks are used as starting points that are adjusted to form volatility judgments about other stocks. Anchoring heuristic implies that such adjustments are typically insufficient. ACAPM converges to CAPM with correct adjustment, so CAPM is a special case of ACAPM. The model provides a unified explanation for the size, value, and momentum effects in the stock market. A ke...
FRP-to-concrete joint assemblies anchored with multiple FRP anchors: experimental investigation
Zhang, H.; Smith, ST
2010-01-01
Higher strains can be developed in fibre-reinforced polymer (FRP) composites which are bonded to the surfaces of concrete members if the FRP is anchored. Anchors made from FRP (also known as FRP spike anchors but herein referred to as FRP anchors) are a promising type of anchorage as they can be applied to a variety of different shaped structural elements and they have been shown to be effective in en-hancing the strain capacity of externally bonded FRP. Limited research, however, has been co...
Ding, Xuanming; Zhang, Ting; Li, Ping; Cheng, Ke
2016-02-01
This paper aims to present a theoretical method to study the bearing performance of vertically loaded large-diameter pipe pile groups. The interactions between group piles result in different bearing performance of both a single pile and pile groups. Considering the pile group effect and the skin friction from both outer and inner soils, an analytical solution is developed to calculate the settlement and axial force in large-diameter pipe pile groups. The analytical solution was verified by centrifuge and field testing results. An extensive parametric analysis was performed to study the bearing performance of the pipe pile groups. The results reveal that the axial forces in group piles are not the same. The larger the distance from central pile, the larger the axial force. The axial force in the central pile is the smallest, while that in corner piles is the largest. The axial force on the top of the corner piles decreases while that in the central pile increases with increasing of pile spacing and decreasing of pile length. The axial force in side piles varies little with the variations of pile spacing, pile length, and shear modulus of the soil and is approximately equal to the average load shared by one pile. For a pile group, the larger the pile length is, the larger the influence radius is. As a result, the pile group effect is more apparent for a larger pile length. The settlement of pile groups decreases with increasing of the pile number in the group and the shear modulus of the underlying soil.
Institute of Scientific and Technical Information of China (English)
Lü Shu-hui; WANG Kui-hua; WU Wen-bing; C. J. LEO
2015-01-01
The dynamic response of pile in layered soil is theoretically investigated when considering the transverse inertia effect. Firstly, the fictitious soil-pile model is employed to simulate the dynamic interaction between the pile and the soil layers beneath pile toe. The dynamic interactions of adjacent soil layers along the vertical direction are simplified as distributed Voigt models. Meanwhile, the pile and fictitious soil-pile are assumed to be viscoelastic Rayleigh-Love rods, and both the radial and vertical displacement continuity conditions at the soil-pile interface are taken into consideration. On this basis, the analytical solution for dynamic response at the pile head is derived in the frequency domain and the corresponding quasi-analytical solution in the time domain is then obtained by means of the convolution theorem. Following this, the accuracy and parameter value of the hypothetical boundaries for soil-layer interfaces are discussed. Comparisons with published solution and measured data are carried out to verify the rationality of the present solution. Parametric analyses are further conducted by using the present solution to investigate the relationships between the transverse inertia effects and soil-pile parameters.
Shaft friction of bored piles in hard clay
International Nuclear Information System (INIS)
The precise prediction of maximum load carrying capacity of bored piles is a complex problem because it is a function of a number of factor. These factor include method of boring, method of concreting. quality of concrete, expertise of the construction staff, the ground conditions etc. besides the pile geometry. The performance of pile load test is therefore, of paramount importance to establish the most economical design of piles especially where bored cast-in-situ piles are to be provided to support a structure. This paper describes the experience gained from four pile load test at a site in the North West Frontier Province of Pakistan where a new cement plant is going to be installed. Geotechnical investigations at the side were carried out to a maximum depth of 60 m. The subsoils at the site are predominantly hard clays within the investigated depth with thin layer of gravels boulders below 40 m depth. Perched water was encountered at various horizons. Four piles of diameter varying from 660 mm to 760 mm and length ranging between 20 m and 47.5 m were subjected to axial loads. The load test data were analyzed using various state of the art techniques including intercept of two tangents, point of change of slope 6 mm net settlement (1), 90 percent and 80 percent Hansen (7), limit value Davisson (2), and Chin (3). Based on a comparison of pile capacities from these methods with the theoretical values, recommendations are made on the approach to estimate the pile capacity in hard clays. Using the pile load test result back calculations were also carried out 10 estimate the appropriate values of pile design parameter such as undrained cohesion and adhesion factor. (author)
Experimental Study on Post Grouting Bearing Capacity of Large Diameter Bored Piles
Directory of Open Access Journals (Sweden)
Wang Duanduan
2015-01-01
Full Text Available Post grouting can improve the inherent defects such as the formation of the mud cake at pile side and the sediment at pile end in the process of bored pile construction. Thus post grouting has been widely used in Engineering. The purpose of this paper is to research the influences of post grouting to pile bearing capacity more systematically and intuitively. Combined with the static load test of four test piles in Weihe River Bridge test area of new airport highway in Xi’an, the bearing capacity and settlement of routine piles and post grouting piles are comparatively analyzed. The test results show that under the same geological condition, post grouting can improve the properties of pile tip and pile shaft soil of bored piles significantly, enhance the ultimate resistance, improve the ultimate bearing capacity and reduce the pile tip settlement. Then post grouting can aim to optimize pile foundation.
Anchors as Semantic Primes in Value Construction: An EEG Study of the Anchoring Effect.
Directory of Open Access Journals (Sweden)
Qingguo Ma
Full Text Available Previous research regarding anchoring effects has demonstrated that human judgments are often assimilated to irrelevant information. Studies have demonstrated that anchors influence the economic valuation of various products and experiences; however, the cognitive explanations of this effect remain controversial, and its neural mechanisms have rarely been explored. In the current study, we conducted an electroencephalography (EEG experiment to investigate the anchoring effect on willingness to accept (WTA for an aversive hedonic experience and the role of anchors in this judgment heuristic. The behavioral results demonstrated that random numbers affect participants' WTA for listening to pieces of noise. The participants asked for higher pay after comparing their WTA with higher numbers. The EEG results indicated that anchors also influenced the neural underpinnings of the valuation process. Specifically, when a higher anchor number was drawn, larger P2 and late positive potential amplitudes were elicited, reflecting the anticipation of more intensive pain from the subsequent noise. Moreover, higher anchors induced a stronger theta band power increase compared with lower anchors when subjects listened to the noises, indicating that the participants felt more unpleasant during the actual experience of the noise. The levels of unpleasantness during both anticipation and experience were consistent with the semantic information implied by the anchors. Therefore, these data suggest that a semantic priming process underlies the anchoring effect in WTA. This study provides proof for the robustness of the anchoring effect and neural evidence of the semantic priming model. Our findings indicate that activated contextual information, even seemingly irrelevant, can be embedded in the construction of economic value in the brain.
Design Considerations for Pile Groups Supporting Marine Structures with Respect to Scour
Yasser E. Mostafa
2012-01-01
Piles supporting marine structures such as jetties, relieving platforms, quay walls and fixed offshore structures are subjected to lateral loads due to berthing and mooring forces, wind, waves, storm surges and current forces. This paper presents some factors that affect the design of pile groups supporting marine structures founded in cohesionless soils. Some main aspects that should be considered in the pile group design are addressed such as pile batter angle, pile group arrangement, pile ...
Numerical Simulation for the Soil-Pile-Structure Interaction under Seismic Loading
Lifeng Luan; Yunbin Liu; Ying Li
2015-01-01
Piles are widely used as reinforcement structures in geotechnical engineering designs. If the settlement of the soil is greater than the pile, the pile is pulled down by the soil, and negative friction force is produced. Previous studies have mainly focused on the interaction of pile-soil under static condition. However, many pile projects are located in earthquake-prone areas, which indicate the importance of determining the response of the pile-soil structure under seismic load. In this pap...
Investigation of Pile- Soil Interaction Subjected to Lateral Loads in Layered Soils
A. Avaei; Ghotbi, Abdoul R.; M. Aryafar
2008-01-01
To stabilize infrastructures such as tall buildings, bridges, etc., piles are used to resist lateral loads created from earth pressure, wind, waves and earthquake extensively. Pile design requires understanding of how the load is transferred from a pile to surrounding soil and vice versa. Pile properties, soil stress-strain behavior and pile-soil interaction play important roles in pile-response subjected to lateral loads. A study was carried out to investigate the effects of above-mentioned ...
Examination of graphite pile radiation conditions of industrial reactors
International Nuclear Information System (INIS)
Radiation states of graphite piles of three industrial uranium-graphite reactors are investigated. The level, composition, distribution of the pile radioactive contamination, parameters of neutron and gamma radiations are determined. The forecast of variation of radionuclide activity in graphite in dependence on the cooling time is developed
Perturbation analysis on post-buckling behavior of pile
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The nonlinear large deflection differential equation, based on the assumption that the subsoil coefficient is the 2nd root of the depth, was established by energy method. The perturbation parameter was introduced to transform the equation to a series of linear differential equations to be solved, and the deflection function according with the boundary condition was considered. Then,the nonlinear higher-order asymptotic solution of post-buckling behavior of a pile was obtained by parameter-substituting. The influencing factors such as bury-depth ratio and stiffness ratio of soil to pile, slenderness ratio on the post-buckling behavior of a pile were analyzed. The results show that the pile is more unstable when the bury-depth ratio and stiffness ratio of soil to pile increase,and although the buckling load increases with the stiffness of soil, the pile may ruin for its brittleness. Thus, in the region where buckling behavior of pile must be taken into account, the high grade concrete is supposed to be applied, and the dynamic buckling behavior of pile needs to be further studied.
Visualization of soil arching in flexible piled embankments
Indian Academy of Sciences (India)
Tuğba Eskışar
2015-10-01
Piled embankments rely on soil arching, but, when geogrid reinforcements are used, membrane action within the reinforcement contributes to load distribution. The arching of soil in unreinforced and reinforced piled embankments is evaluated in this study. A small-scale test apparatus is used to model the settlement up to 5 mm in an embankment with four pile elements. Visual inspection of the soil settlement and soil-reinforcement interaction is important to explain the mechanism of arching. In this study, X-ray Computed Tomography (CT) method was used as a non-destructive technique. The arching of soil between the piles was observed in the case of rigid piles and in the case of flexible piles with grid type of reinforcement. The load carrying capacity increased up to 33% in the case of geogrid reinforcement, and the differential settlement decreased around 35%, proving the efficiency of piled embankments with geogrid reinforcements. It is also shown that, using X-ray CT method and visualization techniques provides a better understanding of soil behavior in a reinforced embankment with the flexible pile foundation system.
Modeling the damming effect of pile foundations (Tomsk city)
Kuzevanov, K. I.; Pokrovsky, D. S.; Pokrovsky, V. D.; Kuzevanov, K. K.
2016-03-01
The authors have considered the impact of pile foundations on the structure of filtration flows in the conditions of urban development. Hydrodynamic simulation methods have shown that a groundwater level rise might occur due to the damming effect that can be created by pile fields in semipermeable rocks. This phenomenon can intensify anthropogenic waterlogging processes in urbanized territories.
A NIM module for efficient amplifier pile-up rejection
International Nuclear Information System (INIS)
A NIM standard module containing four individual circuits for detecting an amplifier pile-up condition is described. Each circuit can be adjusted to match a wide range of amplifier shaping time-constants. Output with a variable delay are provided for signaling a pile-up reject to the data acquisition system
The Influence of Time on Bearing Capacity of Driven Piles
DEFF Research Database (Denmark)
Jensen, J. Lysebjerg; Augustesen, A.; Sørensen, Carsten S.
2004-01-01
In Danish engineering practice, one of the ways to determine the ultimate bearing capacity of an axially loaded pile is by means of geostatic formulas. In the equation describing the contribution from the shaft friction to the total bearing capacity for piles located entirely or partly in clay, a...
Cause Analysis of Wuhan Tianheng Building Pile Accident
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The geological condition and the original structure feature and foundation design of Wuhan Tianheng building are described. The accident appearance of pile foundation in the construction execution of work is illustrated. The generating source of this pile foundation accident is analyzed in great details.``
Ter-Martirosyan Zaven Grigor'evich; Trinh Tuan Viet
2012-01-01
WITH ACCOUNT FOR COMPRESSIBILITY OF THE PILE SHAFT The authors provide their solution to the problem of interaction of a long compressible pile that has a double-layer linear deformable base. The paper demonstrates that taking account of compressible properties of the pile material leads to qualitatively new distribution of shearing stresses over the surface of a cylindrical pile. It is noteworthy that increase of the pile length and stiffness of the upper section of the base raise the sha...
The Analysis of Soil Resistance During Screw Displacement Pile Installation
Krasinski, Adam
2015-02-01
The application of screw displacement piles (SDP) is still increasing due to their high efficiency and many advantages. However, one technological problem is a serious disadvantage of those piles. It relates to the generation of very high soil resistance during screw auger penetration, especially when piles are installed in non-cohesive soils. In many situations this problem causes difficulties in creating piles of designed length and diameter. It is necessary to find a proper method for prediction of soil resistance during screw pile installation. The analysis of screw resistances based on model and field tests is presented in the paper. The investigations were carried out as part of research project, financed by the Polish Ministry of Science and Higher Education. As a result of tests and analyses the empirical method for prediction of rotation resistance (torque) during screw auger penetration in non-cohesive subsoil based on CPT is proposed.
Static Tension Tests on Axially Loaded Pile Segments in Sand
DEFF Research Database (Denmark)
Thomassen, Kristina; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo
showed best agreement with the traditional design method given in the American Petroleum Institute (API) design code. When t-z curves obtained from the test results were compared to t-z curve formulations found in the literature, the Zhang formulation gave good predictions of the initial and post......This paper provides laboratory test results of static axially loaded piles in sand. With a newly developed test setup, the pile-soil interface friction was investigated by using an open-ended steel pile segment with a diameter of 0.5 m. Use of a pile length of 1 m enabled the pile-soil interface...... friction to be analyzed at a given soil horizon while increasing the vertical effective stress in the sand. Test results obtained by this approach can be analyzed as single t-z curves and compared to predictions of unit shaft friction from current design methods for offshore foundations. The test results...
The Analysis of Soil Resistance During Screw Displacement Pile Installation
Directory of Open Access Journals (Sweden)
Krasinski Adam
2015-02-01
Full Text Available The application of screw displacement piles (SDP is still increasing due to their high efficiency and many advantages. However, one technological problem is a serious disadvantage of those piles. It relates to the generation of very high soil resistance during screw auger penetration, especially when piles are installed in non-cohesive soils. In many situations this problem causes difficulties in creating piles of designed length and diameter. It is necessary to find a proper method for prediction of soil resistance during screw pile installation. The analysis of screw resistances based on model and field tests is presented in the paper. The investigations were carried out as part of research project, financed by the Polish Ministry of Science and Higher Education. As a result of tests and analyses the empirical method for prediction of rotation resistance (torque during screw auger penetration in non-cohesive subsoil based on CPT is proposed.
Vertical vibration of a pile in transversely isotropic multilayered soils
Ai, Zhi Yong; Liu, Chun Lin
2015-11-01
A new method for the dynamic response of a vertically loaded single pile embedded in transversely isotropic multilayered soils is proposed in this paper. The dynamic response of the pile is governed by the one-dimensional (1D) vibration theory, and that of transversely isotropic multilayered soils is achieved by using an analytical layer-element method. Then, with the aid of the displacement compatibility and the contact forces equilibrium along the pile-soil contact surface, the dynamic pile-soil interaction problem is solved efficiently. The presented solution method is proved to be correct and efficient by comparing the obtained results with other existing solutions. Selected numerical results are presented to study the influence of mass density ratio, length-radius ratio, frequency of excitation, soil anisotropy and hard soil stratum on the pile vertical impedance.
Pre-Stressed Rope Reinforced Anti-Sliding Pile
Institute of Scientific and Technical Information of China (English)
XU Jun; WANG Chenghua
2006-01-01
Pre-stressed rope reinforced anti-sliding pile is a composite anti-sliding structure. It is made up of pre-stressed rope and general anti-sliding pile. It can bring traditional anti-sliding pile's retaining performance into full play, and to treat with landslide fast and economically. The difference between them is that the pre-stressed rope will transfix the whole anti-sliding pile through a prearranged pipe in this structure. The working mechanics, the design method and economic benefit are studied. The results show that the pre-stressed rope reinforced anti-sliding pile can treat with the small and middle landslides or high slopes well and possess the notable advantage of technology and economic.
Dynamic Soil-Pile Interaction for large diameter monopile foundations
DEFF Research Database (Denmark)
Zania, Varvara
2013-01-01
of the study is to analyse the dynamic interaction of the soil and a single pile embedded in it by accounting for the geometric and stiffness properties of the pile. In doing so, a semi – analytical approach is adopted based on the fundamental solution of horizontal pile vibration by Novak and Nogami...... eigenfrequencies of the soil layer do not affect the soil – pile interaction. The decrease of the eigefrequency of the OWT depends on the aforementioned variation of the dynamic stiffness and the slenderness ratio of the monopile....... left between two restrictive frequency areas. Moreover the design of monopile foundations when subjected to combined lateral and moment loading (the latter arising from the eccentricity of the applied wind pressure) usually dictates a large diameter steel pile with small slenderness ratio. Hence, aim...
Distributed fibre optic strain measurements on a driven pile
Woschitz, Helmut; Monsberger, Christoph; Hayden, Martin
2016-05-01
In civil engineering pile systems are used in unstable areas as a foundation of buildings or other structures. Among other parameters, the load capacity of the piles depends on their length. A better understanding of the mechanism of load-transfer to the soil would allow selective optimisation of the system. Thereby, the strain variations along the loaded pile are of major interest. In this paper, we report about a field trial using an optical backscatter reflectometer for distributed fibre-optic strain measurements along a driven pile. The most significant results gathered in a field trial with artificial pile loadings are presented. Calibration results show the performance of the fibre-optic system with variations in the strain-optic coefficient.
Small asteroids - rubble piles or boulders?
Harris, Alan W.
2013-10-01
The asteroid rotation spin barrier at ~2.2 h period among asteroids 10 km > D > 200 m doesn’t prove all such asteroids are rubble piles, and the faster rotations among smaller asteroids doesn’t require monolithic strength, either. Only a very modest strength, perhaps no more than van der Waals force, might suffice to hold regolith together on a small super-fast rotator (Sanchez & Scheeres, 2013, arXif:1306.1622v1). The problem is that for a constant or only slowly varying strength with respect to diameter, the spin barrier becomes proportional to 1/D below the size where material strength is dominant, or perhaps a bit steeper if strength increases with decreasing D. What we observe in the distribution of asteroid spins versus diameter is that below D ~ 200 m, the spin barrier goes up at least ~D-3.5, if not abruptly. Models with constant or slowly varying strength fail to fit this observation, and the abrupt transition cannot be an observational selection effect: the void in the phase space of rotations would be among the easiest rotations to observe, e.g. the one conspicuous exception, 2001 OE84 (D ~ 0.7 km, P = 0.5 h) was easily and unambiguously measured (Pravec, et al. 2002, Proc. ACM 2002, ESA SP-500, 743-745). This abrupt transition is most easily explained as a real transition in material properties of asteroids in the size range ~200 m diameter, from “rubble pile” to “boulder”, although neither term may be fully descriptive of the actual structure. Two other lines of evidence suggest that this transition in properties is real: the dip in the size-frequency distribution of NEAs is maximum at ~150 m, suggesting that a transition to stronger material structure occurs about there, and we observe, e.g., Tunguska and the recent Chelyabinsk bolide, that bodies in the tens of meters size range entering the atmosphere behave more like solid rocks than rock piles (Boslough & Crawford 2008, Int. J. Imp. Eng. 35, 1441-1448). I encourage those doing computer
Influence of space of double row piles on soil arching effect
Directory of Open Access Journals (Sweden)
Zhao bo
2015-02-01
Full Text Available FLAC3d software, based on continuous theory, is used to analysis influence of space of double row piles on soil arching effect. The result shows that different from single row pile, double row piles will produce soil arching effect at front pile and rear pile severally, this phenomenon is called multiple soil arching effect; the residual load of front of front row pile will increase,the soil arch zone and the soil arching effect will decrease with the continuous increase of double row pile spacing.At the same time the soil arching effect of rear pile decreases, while the soil arching effect of front pile increases and finally the soil arching effect between front pile and rear pile will be equal.
Digitalisation in atomic pile control (1962)
International Nuclear Information System (INIS)
A brief survey is first given of the general theorems of Boodle's algebra and of sequence systems using D.A. Huffmans theory. Some indications are then given concerning the setting-up and the operation of digital computers and also of the principal codes used in digital techniques. It is then shown how digitalisation in atomic pile control makes it possible to use new techniques having the following advantages in particular: greater working safety, a higher degree of centralisation, and suppression of the linear elements. A few examples are given of the application of these techniques to control, particularly with respect to the measurement of the neutronic power and of the period and also of course, to the treatment of the data and the sequence automatisms. The advantage of using digital techniques in the shutdown channels is also examined. Finally a review is given of the technology and the viability of the control devices used. (author)
Cuanalo, Oscar; Polanco, Gabriel; Rivera, Julio
2013-04-01
We report the case of a landslide of hydrocarbon exploration well "Sunuapa 401" located in Chiapas, Mexico. First were identified the determinants and triggers factors (morphology, geology, rain, seismic and volcanic activity, human activity, etc); second we assessed the threat, vulnerability and risk from geotechnical stability analysis (safety factor and critical failure surface); third, by using the methodology of valuation factors, stabilization processes were selected and designed, and finally they were built by Petróleos Mexicanos, in order to avoid a disaster (environmental, ecological and social). These construction processes included drainage elements, flattening and benching of slopes, piles barrier and anchors, shotcrete and reforestation.
Analysis of Wave Fields induced by Offshore Pile Driving
Ruhnau, M.; Heitmann, K.; Lippert, T.; Lippert, S.; von Estorff, O.
2015-12-01
Impact pile driving is the common technique to install foundations for offshore wind turbines. With each hammer strike the steel pile - often exceeding 6 m in diameter and 80 m in length - radiates energy into the surrounding water and soil, until reaching its targeted penetration depth. Several European authorities introduced limitations regarding hydroacoustic emissions during the construction process to protect marine wildlife. Satisfying these regulations made the development and application of sound mitigation systems (e.g. bubble curtains or insulation screens) inevitable, which are commonly installed within the water column surrounding the pile or even the complete construction site. Last years' advances have led to a point, where the seismic energy tunneling the sound mitigation systems through the soil and radiating back towards the water column gains importance, as it confines the maximum achievable sound mitigation. From an engineering point of view, the challenge of deciding on an effective noise mitigation layout arises, which especially requires a good understanding of the soil-dependent wave field. From a geophysical point of view, the pile acts like a very unique line source, generating a characteristic wave field dominated by inclined wave fronts, diving as well as head waves. Monitoring the seismic arrivals while the pile penetration steadily increases enables to perform quasi-vertical seismic profiling. This work is based on datasets that have been collected within the frame of three comprehensive offshore measurement campaigns during pile driving and demonstrates the potential of seismic arrivals induced by pile driving for further soil characterization.
Remedial action for radioactive waste rock piles in China
International Nuclear Information System (INIS)
The Chinese government has conducted remedial action for radioactive waste rock piles since 1990. The radioactive waste rocks produced in the course of geological exploration of uranium deposits are widely distributed over several hundreds of locations in more than 20 provinces in China. The following remedial actions for radioactive waste rock piles have been undertaken in China: 1. Protecting dams for stabilizing the piles have been built. A total length of about 50,000 m of these dams has been completed. 2. Soil layers have been emplaced on the radioactive waste rock piles. The focus of the action is to eliminate the radiation harmful to public health. A total area of 750,000 square meters of soil has been placed on the piles in China. 3. Radioactive waste rock piles have been vegetated. Aesthetic shaping of the landscape in the exploratory district of the uranium deposits is our expectant goal. A total area of about 560,000 square meters of vegetation has been placed on the soil covering the piles. Through these remedial actions, the environmental situation has been extensively improved in the remedial districts. The individual annual effective dose equivalent is less than 1 Sv/a. The radon emission rate is less than 20 pCi/m2.s. The gamma ray external exposure rate has been greatly reduced. Copyright (2001) Material Research Society
Three-dimensional analysis of slopes reinforced with piles
Institute of Scientific and Technical Information of China (English)
高玉峰; 叶茂; 张飞
2015-01-01
Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes.
ANCHORING EFFECT ANALYSIS OF TENSIONED BOLTS
Institute of Scientific and Technical Information of China (English)
夏建中
1997-01-01
The paper analyses quantitatively the anchoring effect of tensioned bolts on surrounding rock strength, and defines two concepts: one is the surrounding rock strength increased amount △τ13 and the other is the strength influence factor k. The anchoring effect of tensioned bolts is considered to increase a strength increased amount △τ13 where △τ13 is the product k and tensioned load p, i. e. △τ13= kp, where k is a function of two variables x and y. The distributive properties both △τ13 and k are also discussed in the paper, obtaining some useful results for designing bolting support parameters.
Ice bustles on quay piles : field studies and numerical simulations
Energy Technology Data Exchange (ETDEWEB)
Loset, S.; Marchenko, A. [Norwegian Univ. of Science and Technology, Trondheim (Norway)]|[Svalbard Univ. Centre, Spitsbergen (Norway)
2008-07-01
The additional gravity action created by the accumulation of ice on coastal structures and piles in cold climates may create a potential threat for the safety of the structures, particularly for mooring and fendering of floating structures and jacket-type structures. The gravity action is particularly critical in areas with changes in water level, such as large tide amplitudes. Ice bustle on piles may also increase the water line, thereby creating more horizontal action from moving ice fields. This study examined the growth and properties of ice bustles on quay piles in the Svea coal harbour, Spitsbergen during the winter and spring of 2007. Their formation was found to be related to super-cooling of piles relative to the temperature of surrounding water, when the heat conductivity of the pile material is higher than the heat conductivity of the water. Ice grows laterally from the surface of the pile at larger depths than the thickness of the surrounding level ice. The bustles are kept in place during water level changes because of the high adhesion between the ice and pile. The vertical and horizontal size of ice bustles formed on cylindrical quay steel piles in the study area was about 1.5 m with slightly downward sloping side walls. At high tide, the top surface coincided with the water level while at low tide, it was almost above the water surface. The Comsol Multiphysics 3.3a mathematical model was used to describe the formation of ice bustle around the cylindrical pile. Ice bustle growth was simulated with a constant water level while taking into consideration changes in tide and water level. This paper also described how the size of ice bustle is influenced by meteorological conditions, time and tidal amplitude. 1 refs., 1 tab., 10 figs.
Analysis of static and dynamic pile-soil-jacket behaviour
Energy Technology Data Exchange (ETDEWEB)
Azadi, Mohammad Reza Emami
1998-12-31
In the offshore industry, recent extreme storms, severe earthquakes and subsidence of the foundation of jacket platforms have shown that new models and methods must take into account the jacket- pile-soil foundation interaction as well as the non-linear dynamic performance/loading effects. This thesis begins with a review of the state of art pile-soil interaction model, recognizing that most existing pile-soil models have been established based on large diameter pile tests on specific sites. The need for site independent and mechanistic pile-soil interaction models led to the development of new (t-z) and (p-y) disk models. These are validated using the available database from recent large diameter pile tests in the North Sea and Gulf of Mexico. The established static disk models are applied for non-linear static analysis of the jacket-pile-soil system under extreme wave loading. Dynamic pile-soil interaction is studied and a new disk-cone model is developed for the non-linear and non-homogeneous soils. This model is applied to both surface and embedded disks in a soil layer with non-linear properties. Simplified non-linear as well as more complex analysis methods are used to study the dynamic response of the jacket platform under extreme sea and seismic loading. Ductility spectra analysis is introduced and used to study the dynamic performance of the jacket systems near collapse. Case studies are used to illustrate the effects of structural, foundation failure characteristics as well as dynamic loading effects on the overall performance of the jacket-pile-soil systems near ultimate collapse. 175 refs., 429 figs., 70 tabs.
Assessing the impact of pile driving upon fish
Hawkins, Anthony
2005-01-01
Pile driving associated with the removal and reconstruction of a jetty was monitored at a busy harbor in the North East of Scotland, adjacent to an important Atlantic salmon river. The main concern was with the impact of noise upon salmon migrating through the lower part of the river estuary. Pile driving was allowed to proceed subject to an agreed program of works to monitor sound levels and ensure least disturbance to salmon. Both percussive and vibratory pile driving took place. Sound-pres...
Monogenean anchor morphometry: systematic value, phylogenetic signal, and evolution.
Khang, Tsung Fei; Soo, Oi Yoon Michelle; Tan, Wooi Boon; Lim, Lee Hong Susan
2016-01-01
Background. Anchors are one of the important attachment appendages for monogenean parasites. Common descent and evolutionary processes have left their mark on anchor morphometry, in the form of patterns of shape and size variation useful for systematic and evolutionary studies. When combined with morphological and molecular data, analysis of anchor morphometry can potentially answer a wide range of biological questions. Materials and Methods. We used data from anchor morphometry, body size and morphology of 13 Ligophorus (Monogenea: Ancyrocephalidae) species infecting two marine mugilid (Teleostei: Mugilidae) fish hosts: Moolgarda buchanani (Bleeker) and Liza subviridis (Valenciennes) from Malaysia. Anchor shape and size data (n = 530) were generated using methods of geometric morphometrics. We used 28S rRNA, 18S rRNA, and ITS1 sequence data to infer a maximum likelihood phylogeny. We discriminated species using principal component and cluster analysis of shape data. Adams's K mult was used to detect phylogenetic signal in anchor shape. Phylogeny-correlated size and shape changes were investigated using continuous character mapping and directional statistics, respectively. We assessed morphological constraints in anchor morphometry using phylogenetic regression of anchor shape against body size and anchor size. Anchor morphological integration was studied using partial least squares method. The association between copulatory organ morphology and anchor shape and size in phylomorphospace was used to test the Rohde-Hobbs hypothesis. We created monogeneaGM, a new R package that integrates analyses of monogenean anchor geometric morphometric data with morphological and phylogenetic data. Results. We discriminated 12 of the 13 Ligophorus species using anchor shape data. Significant phylogenetic signal was detected in anchor shape. Thus, we discovered new morphological characters based on anchor shaft shape, the length between the inner root point and the outer root
Anchor Stress Checking of Security Injection Tank
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
The intention of the calculating is to check the anchor stresses of the security injection tank to know whether the stress is satisfied the code requirements on the basis of all the reaction forces gained in the static, seismic and thermal stress results.
Stone anchors from Minicoy Island, Lakshadweep, India
Digital Repository Service at National Institute of Oceanography (India)
Tripati, S.
at Androth, Kadmat, Kavaratti and Minicoy. In addition to these finds, in recent past an Indo-Arabian type of stone anchor has come to lime light at the Jama Mosque of Funhilol of Minicoy. In this paper an attempt has been made to describe the Indo...
Predicting Anchor Links between Heterogeneous Social Networks
Sajadmanesh, Sina; Khodadadi, Ali
2016-01-01
People usually get involved in multiple social networks to enjoy new services or to fulfill their needs. Many new social networks try to attract users of other existing networks to increase the number of their users. Once a user (called source user) of a social network (called source network) joins a new social network (called target network), a new inter-network link (called anchor link) is formed between the source and target networks. In this paper, we concentrated on predicting the formation of such anchor links between heterogeneous social networks. Unlike conventional link prediction problems in which the formation of a link between two existing users within a single network is predicted, in anchor link prediction, the target user is missing and will be added to the target network once the anchor link is created. To solve this problem, we use meta-paths as a powerful tool for utilizing heterogeneous information in both the source and target networks. To this end, we propose an effective general meta-pat...
Influence of Anchoring on Burial Depth of Submarine Pipelines
Zhuang, Yuan; Li, Yang; Su, Wei
2016-01-01
Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emergency anchoring have been established to derive an anchor impact energy equation for each condition. The required effective burial depth for submarine pipelines has then been calculated via an energy absorption equation for the protection layer covering the submarine pipelines. Finally, the results of the model calculation have been verified by accident case analysis, and the impact of the anchoring height, anchoring water depth and the anchor weight on the required burial depth of submarine pipelines has been further analyzed. PMID:27166952
Influence of Anchoring on Burial Depth of Submarine Pipelines.
Zhuang, Yuan; Li, Yang; Su, Wei
2016-01-01
Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emergency anchoring have been established to derive an anchor impact energy equation for each condition. The required effective burial depth for submarine pipelines has then been calculated via an energy absorption equation for the protection layer covering the submarine pipelines. Finally, the results of the model calculation have been verified by accident case analysis, and the impact of the anchoring height, anchoring water depth and the anchor weight on the required burial depth of submarine pipelines has been further analyzed. PMID:27166952
Numerical Simulation for the Soil-Pile-Structure Interaction under Seismic Loading
Directory of Open Access Journals (Sweden)
Lifeng Luan
2015-01-01
Full Text Available Piles are widely used as reinforcement structures in geotechnical engineering designs. If the settlement of the soil is greater than the pile, the pile is pulled down by the soil, and negative friction force is produced. Previous studies have mainly focused on the interaction of pile-soil under static condition. However, many pile projects are located in earthquake-prone areas, which indicate the importance of determining the response of the pile-soil structure under seismic load. In this paper, the nonlinear, explicit, and finite difference program FLAC3D, which considers the mechanical behavior of soil-pile interaction, is used to establish an underconsolidated soil-pile mode. The response processes of the pile side friction force, the pile axial force, and the soil response under seismic load are also analyzed.
Lateral response of pile foundations in liquefiable soils
Directory of Open Access Journals (Sweden)
Asskar Janalizadeh
2015-10-01
Full Text Available Liquefaction has been a main cause of damage to civil engineering structures in seismically active areas. The effects of damage of liquefaction on deep foundations are very destructive. Seismic behavior of pile foundations is widely discussed by many researchers for safer and more economic design purposes. This paper presents a pseudo-static method for analysis of piles in liquefiable soil under seismic loads. A free-field site response analysis using three-dimensional (3D numerical modeling was performed to determine kinematic loads from lateral ground displacements and inertial loads from vibration of the superstructure. The effects of various parameters, such as soil layering, kinematic and inertial forces, boundary condition of pile head and ground slope, on pile response were studied. By comparing the numerical results with the centrifuge test results, it can be concluded that the use of the p-y curves with various degradation factors in liquefiable sand gives reasonable results.
Residual settlement calculation of geocell cushion over gravel piles
Institute of Scientific and Technical Information of China (English)
陈昌富; 杨宇; 肖淑君; 周志军
2008-01-01
The calculation of residual settlement of bidirectional reinforced composite foundation, which is composed of geocell cushion over gravel piles, was studied. The geocell cushion was modeled as a thin flexible plate with large deflection. Based on the Kirchhoff hypothesis, the governing differential equations and boundary conditions of the deformation of geocell cushion under working load were founded using von Karman method and solved by Galerkin method. On theses bases, the gravel piles and inter-pile soils were assumed as Winkler ground with variable spring stiffness so as to execute the approximate calculation of the residual settlement of the bidirectional reinforced composite foundation. The calculation method was verified by two laboratory experiments concerning settlement of embankments. One experiment was with just geocell cushion installed to treat the soft clay under embankments; another one was with both geocell cushion and gravel piles installed. The results show that the calculated settlement curve and the maximum settlement are closed to the observed ones.
20051655 - Petronas, Capacity of Driven Piles Offshore Malaysia
DEFF Research Database (Denmark)
Augustesen, Anders; Andersen, Lars
This document is the third of four notes concerning the vertical capacity of piles. It includes an assessment of the effect of previous static load testing upon the measured capacity, i.e. preshearing effects....
20051655 - Petronas, Capacity of Driven Piles Offshore Malaysia
DEFF Research Database (Denmark)
Augustesen, Anders
This document is the second of four notes concerning the effects of time (in this case ageing) on the vertical capacity of piles. It includes a critical review of the relevant publications described in note a....
Airborne thermography of temperature patterns in sugar beet piles
Moore, D. G.; Bichsel, S.
1975-01-01
An investigation was conducted to evaluate the use of thermography for locating spoilage areas (chimneys) within storage piles and to subsequently use the information for the scheduling of their processing. Thermal-infrared quantitative scanner data were acquired initially on January 16, 1975, over the storage piles at Moorhead, Minnesota, both during the day and predawn. Photographic data were acquired during the day mission to evaluate the effect of uneven snow cover on the thermal emittance, and the predawn thermography was used to locate potential chimneys. The piles were examined the day prior for indications of spoilage areas, and the ground crew indicated that no spoilage areas were located using their existing methods. Nine spoilage areas were interpreted from the thermography. The piles were rechecked by ground methods three days following the flights. Six of the nine areas delineated by thermography were actual spoilage areas.
Centrifuge modelling of drained lateral pile - soil response
DEFF Research Database (Denmark)
Klinkvort, Rasmus Tofte
remaining tests were used to investigate the pile - soil interaction to gain a better in-sight into the complex problem. A monotonic test series was carried out initially and then pile - soil interaction curves were deduced from these tests and compared with methodologies used today. The results indicate...... was proposed to predict the accumulation of displacement and change in secant stiffness using the observations seen in the centrifuge. With the centrifuge test observation as basis, an cyclic pile - soil interaction element was developed. The element can be used in Winkler type analysis where the soil...... of rigid piles. The tests have been performed in homogeneously dense dry or saturated Fontainebleau sand in order to mimic simplified drained offshore soil conditions. Approximately half of the tests have been carried out to investigate the centrifuge procedure in order to create a methodology of...
Acoustic emission diagnosis of concrete-piles damaged by earthquakes
International Nuclear Information System (INIS)
Earthquakes often impose unexpected damage on structures. Concerning the soundness of the structure, the upper portion is easily estimated by visual observation, while the lower portion located in deep underground is difficult to be estimated. Thus there exist few effective methods to investigate underground structures. In this paper, a new inspection technique for damage evaluation of concrete-piles utilizing acoustic emission (AE) is proposed, and is verified by a series of experiments. Firstly, such basic characteristics as the attenuation and effective wave-guides for detecting AE underground, are examined through laboratory tests. Secondary, fracture tests of full-scale prefabricated concrete piles are conducted, and the characteristics of the AE are examined. Finally, actual concrete-piles attacked by the 1995 Great Hanshin Earthquake are investigated. Results confirm that the estimated damages by the proposed method are in good agreement with actual damaged locations. Thus, the method is very effective for the diagnosis of the concrete-piles.
Stone anchors of India: Findings, classification and significance.
Digital Repository Service at National Institute of Oceanography (India)
Tripati, S.
Honolulu, Hawaii, May 12-16, 2014, Vol. 2: 973-986 973 Stone anchors of India: Findings, Classification and Significance Sila Tripati CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India Email: sila@nio.org Abstract Various.... The making of anchors from the hero stones indicates their alternative use (Sila Tripati and Patnaik, 2008). Classification Stone anchors are classified according to character, shape and region. In general stone anchors have been classified...
Todd McElroy; Keith Dowd
2007-01-01
Previous research on anchoring has shown this heuristic to be a very robust psychological phenomenon ubiquitous across many domains of human judgment and decision-making. Despite the prevalence of anchoring effects, researchers have only recently begun to investigate the underlying factors responsible for how and in what ways a person is susceptible to them. This paper examines how one such factor, the Big-Five personality trait of openness-to-experience, influences the effect of previously p...
Jointless and Smoother Bridges: Behavior and Design of Piles
Frosch, Robert J; Chovichien, Voraniti; Durbin, Katrinna; Fedroff, David
2006-01-01
Integral abutment bridges have been used in the United States for decades. By eliminating expensive expansion joints, the piles supporting the end bent accommodate the total thermal movement of the bridge. Currently, integral bridges are designed based upon experience, and a rational design specification has not been developed. Furthermore, the interaction of the abutment, pile, and soil remains uncertain. A better understanding regarding the behavior of this system is needed. The objective o...
Pile Structure Program, Projected Start Date : January 1, 2010 (Implementation).
Energy Technology Data Exchange (ETDEWEB)
Collins, Chris; Corbett, Catherine [Lower Columbia River Estuary Partnership; Ebberts, Blaine [U.S. Army Corps of Engineers
2009-07-27
The 2008 Federal Columbia River Power System Biological Opinion includes Reasonable and Prudent Alternative 38-Piling and Piling Dike Removal Program. This RPA directs the Action Agencies to work with the Estuary Partnership to develop and implement a piling and pile dike removal program. The program has since evolved to include modifying pile structures to enhance their habitat value and complexity by adding large woody debris. The geographic extent of the Pile Structure Program (PSP) includes all tidally-influenced portions of the lower Columbia River below Bonneville Dam; however, it will focus on the mainstem. The overarching goal of the PSP is to enhance and restore ecosystem structure and function for the recovery of federally listed salmonids through the active management of pile structures. To attain this goal, the program team developed the following objectives: (1) Develop a plan to remove or modify pile structures that have lower value to navigation channel maintenance, and in which removal or modification will present low-risk to adjacent land use, is cost-effective, and would result in increased ecosystem function. (2) Determine program benefits for juvenile salmonids and the ecosystem through a series of intensively monitored pilot projects. (3) Incorporate best available science and pilot project results into an adaptive management framework that will guide future management by prioritizing projects with the highest benefits. The PSP's hypotheses, which form the basis of the pilot project experiments, are organized into five categories: Sediment and Habitat-forming Processes, Habitat Conditions and Food Web, Piscivorous Fish, Piscivorous Birds, and Toxic Contaminant Reduction. These hypotheses are based on the effects listed in the Estuary Module (NOAA Fisheries in press) and others that emerged during literature reviews, discussions with scientists, and field visits. Using pilot project findings, future implementation will be adaptively managed
In-pile test of Qinshan PWR fuel bundle
International Nuclear Information System (INIS)
In-pile test of Qinshan Nuclear Power Plant PWR fuel bundle has been conducted in HWRR HTHP Test loop at CIAE. The test fuel bundle was irradiated to an average burnup of 25000 Mwd/tU. The authors describe the structure of (3 x 3-2) test fuel bundle, structure of irradiation rig, fuel fabrication, irradiation conditions, power and fuel burnup. Some comments on the in-pile performance for fuel bundle, fuel rod and irradiation rig were made
Guidelines for the Protection of Steel Piles : Corrosive Marine Environment
Rhodes, Graham
2011-01-01
The corrosion of steel is a common phenomenon. In a marine environment, steel is corroded at an accelerated rate due to the atmospheric conditions. To combat this corrosion, steel piles are coated in order to protect them. As a major supplier of steel piles, Rautaruukki Oyj (Ruukki) commissioned this project in order to streamline their coating process. Currently Ruukki supplies a different coating system for almost every job; the aim of the project was to reduce the number of systems used to...
Pile groups under deep expansion: a case history
Alonso Pérez de Agreda, Eduardo; Sauter, Simon; Ramon Tarragona, Anna
2015-01-01
A viaduct in a high speed railway line experienced severe heave of its central pillars as a result of deep expansion of an anhydrite rock. Bridge pillars were founded on pile groups which experienced vertical heave displacements as well as lateral displacements and rotations. A semi-analytical solution for the response of a pile group under loading and arbitrary located soil expansion was developed integrating fundamental solutions for the elastic half-space. The procedure was first validated...
Golden Herbs used in Piles Treatment: A Concise Report
Rajani Chauhan; Km. Ruby; Jaya Dwivedi
2012-01-01
Herbal medicine is also called phytomedicine. It is refers to using a plant's seeds, berries, roots, leaves, bark, or flowers for disease treatment.Herbs have many golden phytochemicals or secondary metabolites to treat disease. They have a long tradition of use outside of conventional medicine. Hemorrhoids or Piles treatment through Herbs has been effective and a golden treatment without any side-effects. There are some herbs which is useful in piles treatment such as Aesculus hippocastanum,...
THE NEW STRUCTURE OF A PLATE-PILE FOUNDATION
Directory of Open Access Journals (Sweden)
SAMORODOV О. V.
2016-01-01
Full Text Available Raising of problem. In the construction of high-rise buildings with significant loads on foundations and bedding at the base of not rocky soils tend to use the most common pile foundation to reduce the deformation and correspond to regulations [1] on the maximum permissible deformation. Monitoring of the stress-strain state (SSS pile foundations constructed buildings shows the existing reserves of bearing capacity on the one hand - soil bases of the second group of limit states, on the other - the foundation of the first group of limit states by regulating the SSS foundation during construction and exploitation. Therefore, are increasingly using more progressive structure of foundations consisting of piles and of plate, as well as methods for their construction [2 - 10], however, in their design there are a number of disadvantages associated with the ambiguity of the application of methods for the calculation of such structures, which allows to do only partial conclusions and recommendations. Purpose. Is proposing the new structure of a plate-pile foundation, which overcomes the drawbacks of the existing design solutions and methods of consruction their, as well as is proposing an engineering method of a determination of basic parameters. Conclusion. Is proposes the new structure of a plate-pile foundation and the method of a determination of basic parameters his in the design of a soil base to the maximum permissible deformation Su buildings. Efficiency of application this type plate-pile foundation obtained by rational distribution resistance between a plate and piles, when under load from the building to the first work fully incorporated plate that allows maximum deformed for plate, and then the piles - due to of the hinge connection with the plate. Thus, depending on the maximum permissible deformation for buildings resistance of plate part of a full load of more than 50%, that significantly reduces the consumption of concrete.
Axial Non-linear Dynamic Soil-Pile Interaction - Keynote
Holeyman A.; Whenham V.
2014-01-01
This keynote lecture describes recent analytical and numerical advances in the modeling of the axial nonlinear dynamic interaction between a single pile and its embedding soil. On one hand, analytical solutions are developed for assessing the nonlinear axial dynamic response of the shaft of a pile subjected to dynamic loads, and in particular to vibratory loads. Radial inhomogeneity arising from shear modulus degradation is evaluated over a range of parameters and compared with those obtained...
INTERACTION BETWEEN LONG PILES AND THE SOIL BODY EXPOSED TO NON-LINEAR DEFORMATIONS
Telichenko Valeriy Ivanovich; Ter-Martirosyan Zaven Grigor'evich
2012-01-01
Theoretical and numeral solutions to the problem of interaction between a long pile and the heterogeneous soil body are considered in the article. It has been discovered that the distribution of stresses between bottom and side sections of a pile depends on elastic and plastic properties of soils and the pile length-to-diameter ratio. Optimal geometric parameters of a pile can be derived by means of the optimal stress distribution between side and bottom sections of a pile. The problem of...
Institute of Scientific and Technical Information of China (English)
王铁成; 杨志坚; 赵海龙; 王文进
2015-01-01
Based on the results of four prestressed high strength concrete(PHC)pile-pile cap connections under cyclic loading,the failure patterns and the mode of the specimens are described. The strain of pile,anchor bars and carbon fiber-reinforced polymer(CFRP),hysteretic curve,bearing capacity and displacement ductility of connections are analyzed. The test results show that the cap of specimens appeared to be a squeezing failure. The anchor bars lost con-straint,and formed a hinge joint that resulted in the connection rotation being unrestricted and the rotation capacity of connection being increased. PHC pile reinforced by steel fiber and non-prestressed steel bars can improve the dis-placement ductility of connections. The connections should be designed with enough rotating capacity,which ensures that the cap will not be damaged by squeezing or prying due to the rotating of the pile end. The finite element software OpenSees was used to simulate the nonlinear behavior of pile-cap connections under cyclic loading. Comparison be-tween analytical and experimental results shows that the proposed modeling technique is capable of accurately describ-ing the cyclic behavior of the connections.%对4个预应力高强混凝土(PHC)管桩与承台连接节点进行了低周往复荷载试验，描述了试件的破坏过程和形态，分析了桩身混凝土、锚固钢筋以及碳纤维约束预应力混凝土管桩(CFRP)的应变，对构件的滞回曲线、承载力和位移延性等进行了研究。试验结果表明，在弯矩作用下，节点区域混凝土被压碎，节点区锚固钢筋约束减弱，形成铰接点，节点转动能力变大；在桩身混凝土中掺入钢纤维以及配置非预应力筋可以提高节点的位移延性；在进行节点设计时，应保证承台不会由于桩端转动时产生的挤压力或撬力作用过早地发生破坏。采用有限元分析软件OpenSees对节点在往复荷载作用下的受力性能进行了模拟分
How curved membranes recruit amphipathic helices and protein anchoring motifs
DEFF Research Database (Denmark)
Hatzakis, Nikos; Bhatia, Vikram Kjøller; Larsen, Jannik;
2009-01-01
: membrane-anchored proteins. The fact that unrelated structural motifs such as alpha-helices and alkyl chains sense MC led us to propose that MC sensing is a generic property of curved membranes rather than a property of the anchoring molecules. We therefore anticipate that MC will promote the...... redistribution of proteins that are anchored in membranes through other types of hydrophobic moieties....
33 CFR 401.14 - Anchor marking buoys.
2010-07-01
... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Anchor marking buoys. 401.14 Section 401.14 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.14 Anchor marking buoys. A highly visible anchor marking...
Students' Anchoring Predisposition: An Illustration from Spring Training Baseball
Mohrweis, Lawrence C.
2014-01-01
The anchoring tendency results when decision makers anchor on initial values and then make final assessments that are adjusted insufficiently away from the initial values. The professional literature recognizes that auditors often risk falling into the judgment trap of anchoring and adjusting (Ranzilla et al., 2011). Students may also be unaware…
Slime thickness evaluation of bored piles by electrical resistivity probe
Chun, Ok-Hyun; Yoon, Hyung-Koo; Park, Min-Chul; Lee, Jong-Sub
2014-09-01
The bottoms of bored piles are generally stacked with soil particles, both while boreholes are being drilled, and afterward. The stacked soils are called slime, and when loads are applied on the pile, increase the pile settlement. Thus to guarantee the end bearing capacity of bored piles, the slime thickness should be precisely detected. The objective of this study is to suggest a new method for evaluating the slime thickness, using temperature compensated electrical resistivity. Laboratory studies are performed in advance, to estimate and compare the resolution of the electrical resistivity probe (ERP) and time domain reflectometry (TDR). The electrical properties of the ERP and TDR are measured using coaxial type electrodes and parallel type two-wire electrodes, respectively. Penetration tests, conducted in the fully saturated sand-clay mixtures, demonstrate that the ERP produces a better resolution of layer detection than TDR. Thus, field application tests using the ERP with a diameter of 35.7 mm are conducted for the investigation of slime thickness in large diameter bored piles. Field tests show that the slime layers are clearly identified by the ERP: the electrical resistivity dramatically increases at the interface between the slurry and slime layer. The electrical resistivity in the slurry layer inversely correlates with the amount of circulated water. This study suggests that the new electrical resistivity method may be a useful method for the investigation of the slime thickness in bored piles.
Axial Non-linear Dynamic Soil-Pile Interaction - Keynote
Directory of Open Access Journals (Sweden)
Holeyman A.
2014-01-01
Full Text Available This keynote lecture describes recent analytical and numerical advances in the modeling of the axial nonlinear dynamic interaction between a single pile and its embedding soil. On one hand, analytical solutions are developed for assessing the nonlinear axial dynamic response of the shaft of a pile subjected to dynamic loads, and in particular to vibratory loads. Radial inhomogeneity arising from shear modulus degradation is evaluated over a range of parameters and compared with those obtained by other authors and by a numerical radial discrete model simulating the pile and soil movements from integration of the laws of motion. New approximate non linear solutions for axial pile shaft behaviour developed from general elastodynamic equations are presented and compared to existing linear solutions. The soil non linear behaviour and its ability to dissipate mechanical energy upon cyclic loading are shown to have a significant influence on the mechanical impedance provided by the surrounding soil against pile shaft movement. The limitations of over-simplified modelling of pile response are highlighted.
International Nuclear Information System (INIS)
Part 1: Experimental piles were built in three geographical locations during May-Sept. 1989. Logging residues consisted of 95% spruce and 5% pine. Height of the piles varied between 80 and 230 cm. Needles were collected by placing drawers under 40 randomely chosen piles. The drawers were emptied every two weeks during the storage period. Natural needle loss was between 18 and 32% of the total amount of needles after the first two months of storage. At the end of the storage period, 24-42% of the needles had fallen down to the drawers. At the end of the experiment the total needle fall was 95-100% in the shaken piles. According to the results of this study piles smaller than 150 cm had the most effective needle fall. Piles should be placed on open places where the air and sun heat penetrate and dry them. Needles were the most sensitive fraction to variations in precipitation compared to the other components, such as branches. Piles usually dried quickly, but they also rewet easily. This was especially true in the smaller piles. The lowest moisture content was measured at the end of June. The ash content in needles varied between 4 and 8%. 16 refs., 15 figs. Part 2: Three field experiments were equipped with no-tension humus lysimeters. Pairs of lysimeters with the same humus/field layer vegetation material were placed in pairs, one under a pile of felling residues and another in the open clear felling. Leaching of nitrogen as well as pH and electric conductivity in the leachate was followed through sampling of the leachate at regular intervals. The results from the investigation show that: * the amount of leachate was higher in lysimeters in the open clear felling, * pH in the leachate was initially lower under piles of felling residues, * the amount of nitrogen leached was higher in the open clear felling. Thus, storing of felling residues in piles during the summer season did not cause any increase in nitrogen leaching, which had been considered to be a risk
Energy Technology Data Exchange (ETDEWEB)
Palmer, E. [Westinghouse Savannah River Company, AIKEN, SC (United States)
1997-04-28
Coal storage piles, their associated coal pile runoff basins and ash basins could potentially have adverse environmental impacts, especially on groundwater. This report presents and summarizes SRS groundwater and soil data that have been compiled. Also, a result of research conducted on the subject topics, discussions from noted experts in the field are cited. Recommendations are made for additional monitor wells to be installed and site assessments to be conducted.
Aminfar, Ali; Ahmadi, Hamid; Aminfar, Mohammad Hossein
2016-06-01
Offshore jacket-type platforms are attached to the seabed by long batter piles. In this paper, results from a finite element analysis, verified against experimental data, are used to study the effect of the pile's inclination angle, and its interaction with the geometrical properties of the pile and the geotechnical characteristics of the surrounding soil on the behavior of the inclined piles supporting the jacket platforms. Results show that the inclination angle is one of the main parameters affecting the behavior of an offshore pile. We investigated the effect of the inclination angle on the maximum von Mises stress, maximum von Mises elastic strain, maximum displacement vector sum, maximum displacement in the horizontal direction, and maximum displacement in the vertical direction. The pile seems to have an operationally optimal degree of inclination of approximately 5°. By exceeding this value, the instability in the surrounding soil under applied loads grows extensively in all the geotechnical properties considered. Cohesive soils tend to display poorer results compared to grained soils.
Energy Technology Data Exchange (ETDEWEB)
Strege, D.E.
1955-03-17
This report covers the examination of thirteen process tubes seven from F Pile, three from C Pile and three from D Pile. Five of the thirteen tubes were removed because they were leakers, four from F Pile and one from C Pile. One tube from F Pile and one from D Pile were removed. Reactor Section had requested the removal of two from F Pile to check for external corrosion. Two tubes, small diameter old pile annulus, were removed from C Pile under PT 105-519-E, ``Raising Permissible Outlet Water Temperatures of Certain Tubes at C Pile.`` Two tubes were removed from D Pile under PT 105-525-E, ``Effects of Water Quality on Operations.`` Visual inspection was made of the inside and outside surfaces of the tubes before and after cleaning in a cold 10 per cent nitric acid solution. Samples varying from one to four inches in length were taken from each section for metallurgical examination to determine depth of pitting, wall thickness, and spot check the 72-S cladding thickness. These determinations were made at selected points in each section on what appeared to be the area of severest attack.
Seismic Demands for Pile-Supported Wharf Structures with Batter Piles
Directory of Open Access Journals (Sweden)
Rouhollah Amirabadi
2012-09-01
Full Text Available This study develops an optimal Probabilistic Seismic Demand Model (PSDM for pile-supported wharves whit batter plies. Four bins with twenty non-near-field ground motions and three typical pile-supported wharf structures from western United States ports are used to determine an optimal PSDM by using Probabilistic Seismic Demand Analysis (PSDA. PSDA is used to compute the relationship between Engineering Demand Parameters (EDPs and earthquake Intensity Measures (IMs. An optimal PSDM should be practical, sufficient, effective and efficient-all tested through several IM-EDP pairs. It has been found that for these types of structures, the optimal model comprises a spectral IM, such as spectral acceleration and one of several EDPs. These EDPs are considered for local (moment curvature ductility factor, intermediate (displacement ductility factor and horizontal displacement of embankment and global (differential settlement between deck and behind land response quantities. The considered PSDMs are a critical component in performance-based seismic design and seismic risk assessment. Results can be used in probabilistic framework for performance-based design developed by Pacific Earthquake Engineering Research (PEER center.
Kumari, Priyanka; Lee, Joonhee; Choi, Hong-Lim
2016-04-01
We studied airborne contaminants (airborne particulates and odorous compounds) emitted from compost facilities in South Korea. There are primarily two different types of composting systems operating in Korean farms, namely mechanical aerated pile composting (MAPC) and aerated static pile composting (SAPC). In this study, we analyzed various particulate matters (PM10, PM7, PM2.5, PM1, and total suspended particles), volatile organic compounds and ammonia, and correlated these airborne contaminants with microclimatic parameters, i.e., temperature and relative humidity. Most of the analyzed airborne particulates (PM7, PM2.5, and PM1) were detected in high concentration at SAPC facilities compered to MAPC; however these differences were statistically non-significant. Similarly, most of the odorants did not vary significantly between MAPC and SAPC facilities, except for dimethyl sulfide (DMS) and skatole. DMS concentrations were significantly higher in MAPC facilities, whereas skatole concentrations were significantly higher in SAPC facilities. The microclimate variables also did not vary significantly between MAPC and SAPC facilities, and did not correlate significantly with most of the airborne particles and odorous compounds, suggesting that microclimate variables did not influence their emission from compost facilities. These findings provide insight into the airborne contaminants that are emitted from compost facilities and the two different types of composting agitation systems. PMID:26949962
Geodesic defect anchoring on nematic shells.
Mirantsev, Leonid V; Sonnet, André M; Virga, Epifanio G
2012-08-01
Nematic shells are colloidal particles coated with nematic liquid crystal molecules, which may freely glide and rotate on the colloid's surface while keeping their long axis on the local tangent plane. Molecular dynamics simulations on a nanoscopic spherical shell indicate that under appropriate adhesion conditions for the molecules on the equator, the equilibrium nematic texture exhibits at each pole a pair of +1/2 defects so close to one another to be treated as one +1 defect. Spirals connect the polar defects, though the continuum limit of the interaction potential would not feature any elastic anisotropy. A molecular averaging justifies an anchoring defect energy that feels the geodesics emanating from the defect. All our observations are explained by such a geodesic anchoring, which vanishes on flat manifolds. PMID:23005713
Recent Study of Drag Embedment Plate Anchors in China
Institute of Scientific and Technical Information of China (English)
Haixiao Liu
2012-01-01
Experimental and theoretical studies of drag embedment plate anchors recently carried out in Tianjin University are summarized in this research paper,which involve a series of important topics relevant to the study of drag anchors.The techniques for measuring the trajectory and movement direction of drag anchors in soils,the techniques for measuring the moving embedment point and reverse catenary shape of the embedded drag line,the penetration mechanism and kinematic behavior of drag anchors,the ultimate embedment depth of drag anchors,the movement direction of the anchor with an arbitrary fluke section,the reverse catenary properties of the embedded drag line,the interactional properties between drag anchor and installation line,the kinematic model of drag anchors in seabed soils,and the analytical method for predicting the anchor trajectory in soils will all be examined.The present work remarkably reduces the uncertainties in design and analysis of drag embedment plate anchors,and is beneficial to improving the application of this new type of drag anchor in offshore engineering.
Anchoring in a novel bimanual coordination pattern.
Maslovat, Dana; Lam, Melanie Y; Brunke, Kirstin M; Chua, Romeo; Franks, Ian M
2009-02-01
Anchoring in cyclical movements has been defined as regions of reduced spatial or temporal variability [Beek, P. J. (1989). Juggling dynamics. PhD thesis. Amsterdam: Free University Press] that are typically found at movement reversal points. For in-phase and anti-phase movements, synchronizing reversal points with a metronome pulse has resulted in decreased anchor point variability and increased pattern stability [Byblow, W. D., Carson, R. G., & Goodman, D. (1994). Expressions of asymmetries and anchoring in bimanual coordination. Human Movement Science, 13, 3-28; Fink, P. W., Foo, P., Jirsa, V. K., & Kelso, J. A. S. (2000). Local and global stabilization of coordination by sensory information. Experimental Brain Research, 134, 9-20]. The present experiment examined anchoring during acquisition, retention, and transfer of a 90 degrees phase-offset continuous bimanual coordination pattern (whereby the right limb lags the left limb by one quarter cycle), involving horizontal flexion about the elbow. Three metronome synchronization strategies were imposed: participants either synchronized maximal flexion of the right arm (i.e., single metronome), both flexion and extension of the right arm (i.e., double metronome within-limb), or flexion of each arm (i.e., double metronome between-limb) to an auditory metronome. In contrast to simpler in-phase and anti-phase movements, synchronization of additional reversal points to the metronome did not reduce reversal point variability or increase pattern stability. Furthermore, practicing under different metronome synchronization strategies did not appear to have a significant effect on the rate of acquisition of the pattern. PMID:18842313
Molecular Conductance: Chemical Trends of Anchoring Groups
Ke, San-Huang; Baranger, Harold U.; Yang, Weitao
2004-01-01
Combining density functional theory calculations for molecular electronic structure with a Green function method for electron transport, we calculate from first principles the molecular conductance of benzene connected to two Au leads through different anchoring atoms -- S, Se, and Te. The relaxed atomic structure of the contact, different lead orientations, and different adsorption sites are fully considered. We find that the molecule-lead coupling, electron transfer, and conductance all dep...
Anchor Toolkit - a secure mobile agent system
Mudumbai, Srilekha S.; Johnston, William; Essiari, Abdelilah
2008-01-01
Mobile agent technology facilitates intelligent operation in software systems with less human interaction. Major challenge to deployment of mobile agents include secure transmission of agents and preventing unauthorized access to resources between interacting systems, as either hosts, or agents, or both can act maliciously. The Anchor toolkit, designed by LBNL, handles the transmission and secure management of mobile agents in a heterogeneous distributed computing environment. It provide...
Anchoring Heuristic and the Equity Premium Puzzle
Siddiqi, Hammad
2015-01-01
What happens when the anchoring and adjustment heuristic of Tversky and Kahneman (1974) is incorporated in the standard consumption-based capital asset pricing model (CCAPM)? The surprising finding is that it not only resolves the high equity-premium and low risk-free rate puzzles with a low risk-aversion coefficient, but also provides a unified framework for understanding countercyclical equity-premium, excess volatility, size, value, and momentum effects, and abnormal returns and volatiliti...
Dynamic load testing on the bearing capacity of prestressed tubular concrete piles in soft ground
Yu, Chuang; Liu, Songyu
2008-11-01
Dynamic load testing (DLT) is a high strain test method for assessing pile performance. The shaft capacity of a driven PTC (prestressed tubular concrete) pile in marine soft ground will vary with time after installation. The DLT method has been successfully transferred to the testing of prestressed pipe piles in marine soft clay of Lianyungang area in China. DLT is investigated to determine the ultimate bearing capacity of single pile at different period after pile installation. The ultimate bearing capacity of single pile was founded to increase more than 70% during the inventing 3 months, which demonstrate the time effect of rigid pile bearing capacity in marine soft ground. Furthermore, the skin friction and axial force along the pile shaft are presented as well, which present the load transfer mechanism of pipe pile in soft clay. It shows the economy and efficiency of DLT method compared to static load testing method.
Seismic response of tall building considering soil-pile-structure interaction
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The seismic behavior of tall buildings can be greatly affected by non-linear soil-pile interaction during strongearthquakes. In this study a 20-storey building is examined as a typical structure supported on a pile foundation for differentconditions: (1) rigid base, i.e. no deformation in the foundation: (2) linear soil-pile system; and (3) nonlinear soil-pile system.The effects of pile foundation displacements on the behavior of tall building are investigated, and compared with the behavior ofbuildings supported on shallow foundation. With a model of non-reflective boundary between the near field and far field,Novak's method of soil-pile interaction is improved. The computation method for vibration of pile foundations and DYNANcomputer program are introduced comprehensively. A series of dynamic experiments have been done on full-scale piles,including single pile and group, linear vibration and nonlinear vibration, to verify the validity of boundary zone model.
Finite Element Investigations on the Interaction between a Pile and Swelling Clay
DEFF Research Database (Denmark)
Kaufmann, Kristine Lee; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust
This paper aims to investigate the interaction between a pile and a swelling soil modelled as a cohesive soil subjected to unloading. The investigations include analyses of the heave of the excavation level, shear stresses at the soil–pile interface and internal pile forces based on a case study of...... Little Belt Clay. The case study involves a circular concrete pile installed in clay immediately after an excavation. The influence of the swelling soil on the soil–pile interaction and the internal pile forces are analysed by solely observing the upper pile part positioned in the swelling zone. For the...... surrounding soil implies upward shear stresses at the soil–pile interface leading to tensile vertical stresses in the pile. In the current case, they exceed the tensile strength of concrete. The tensile vertical stresses peak after 35-50 years. However, the heave of the soil continues for additional 300 years...
Seismic response of tall building considering soil-pile-structure interaction
Han, Yingcai
2002-06-01
The seismic behavior of tall buildings can be greatly affected by non-linear soil-pile interaction during strong earthquakes. In this study a 20-storey building is examined as a typical structure supported on a pile foundation for different conditions: (1) rigid base, i.e. no deformation in the foundation: (2) linear soil-pile system; and (3) nonlinear soil-pile system. The effects of pile foundation displacements on the behavior of tall building are investigated, and compared with the behavior of buildings supported on shallow foundation. With a model of non-reflective boundary between the near field and far field, Novak’s method of soil-pile interaction is improved. The computation method for vibration of pile foundations and DYNAN computer program are introduced comprehensively. A series of dynamic experiments have been done on full-scale piles, including single pile and group, linear vibration and nonlinear vibration, to verify the validity of boundary zone model.
The Analysis Stability of Anchor Retaining Wall
International Nuclear Information System (INIS)
The construction of anchored retaining walls reach every day in the field of Civil Engineering especially in public works. Their dimensioning and stability are the axes of research for geotechnical. The rule is to reduce the active forces of the slide and increase the effective normal stress on the rupture surface. So that, we anchored tied-back (constituted by steel cables) in the stable ground located under the failure surface and we apply at the top a traction force. This effort can be distributed over the ground surface by means of small plates or massive reinforced concrete. The study of the stability of anchored retaining wall was also performed by using software GEO4. Many cases can be solved using analytical solutions available in the group GEO4 program, but for our standard model solution studied analytically proved unsatisfactory so we used a numerical analysis based on the method of finite element in this program. The results obtained by numerical study were interpreted to identify the precision numerical predictions. Moreover these methods were useful and economics in the realization of reinforced slopes by tied-buck. (author)
Institute of Scientific and Technical Information of China (English)
刘汉龙; 陈育民; 赵楠
2008-01-01
Pile foundation is widely used in the offshore engineering. The pile can be seriously destroyed by the soil liquefaction during strong earthquakes. The potentials of liquefaction and damages of pile foundation due to the liquefaction can be reduced by the implementation of the drainage in the liquefiable foundation. A patented pile technology, named rigidity-drain pile, was introduced. The partial section of the pile body was filled by materials with higher penetrability which forms some effective drainage channels in the pile. The principles and construction methods were presented. 3D models for both rigidity-drain pile and ordinary pile were built in FLAC3D code. The dynamic loadings were applied on the bottom of the model. According to the numerical results, in the case of the rigidity-drain pile, the water in the relevant distance range around the pile flows toward the pile drainage, the contour of the pore pressure shows a funnel form. Contrast to the ordinary pile, the rigidity-drain pile can dissipate the accumulated excess pore water, maintain effective stress and obviously reduce the possibility of surrounding soil liquefaction.
Directory of Open Access Journals (Sweden)
Ter-Martirosyan Zaven Grigor'evich
2012-07-01
The authors provide their solution to the problem of interaction of a long compressible pile that has a double-layer linear deformable base. The paper demonstrates that taking account of compressible properties of the pile material leads to qualitatively new distribution of shearing stresses over the surface of a cylindrical pile. It is noteworthy that increase of the pile length and stiffness of the upper section of the base raise the share of the load perceived by the surface of the pile. Besides, in particular conditions of the soil environment, the load perceived by the lower section of the base may reach approximately 20-30 % of the total load.
Directory of Open Access Journals (Sweden)
Zhao Feng
2015-01-01
Full Text Available The slurry wall bored grouting has some defects. The pile-base post grouting technique can efficiently make up these defects and greatly improve the bearing capacity. Based on the pile-base post grouting technique and its process analysis, this paper carries out a detailed analysis about the improvement of mechanism of bearing capacity and mechanism of spherical expansion by the use of pile-base post grouting technique, as well as the estimation method of the bearing capacity of pile-base post grouting pile, which has a certain reference value for theoretical research and technical application of the technique.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
A glycosylphosphatidylinositol (GPI) anchor is a common but complex C-terminal post-translational modification of extracellular proteins in eukaryotes. Here we investigate the problem of correctly annotating GPI-anchored proteins for the growing number of sequences in public databases. We developed a computational system, called FragAnchor, based on the tandem use of a neural network (NN) and a hidden Markov model (HMM). Firstly, NN selects potential GPI-anchored proteins in a dataset, then HMM parses these potential GPI signals and refines the prediction by qualitative scoring. FragAnchor correctly predicted 91% of all the GPI-anchored proteins annotated in the Swiss-Prot database.In a large-scale analysis of 29 eukaryote proteomes, FragAnchor predicted that the percentage of highly probable GPI-anchored proteins is between 0.21% and 2.01%. The distinctive feature of FragAnchor, compared with other systems,is that it targets only the C-terminus of a protein, making it less sensitive to the background noise found in databases and possible incomplete protein sequences. Moreover, FragAnchor can be used to predict GPI-anchored proteins in all eukaryotes. Finally, by using qualitative scoring, the predictions combine both sensitivity and information content. The predictor is publicly available at http: // navet. ics. hawaii.edu/～fraganchor/NNHMM/NNHMM.html.
Robotic Ankle for Omnidirectional Rock Anchors
Parness, Aaron; Frost, Matthew; Thatte, Nitish
2013-01-01
Future robotic exploration of near-Earth asteroids and the vertical and inverted rock walls of lava caves and cliff faces on Mars and other planetary bodies would require a method of gripping their rocky surfaces to allow mobility without gravitational assistance. In order to successfully navigate this terrain and drill for samples, the grippers must be able to produce anchoring forces in excess of 100 N. Additionally, the grippers must be able to support the inertial forces of a moving robot, as well gravitational forces for demonstrations on Earth. One possible solution would be to use microspine arrays to anchor to rock surfaces and provide the necessary load-bearing abilities for robotic exploration of asteroids. Microspine arrays comprise dozens of small steel hooks supported on individual suspensions. When these arrays are dragged along a rock surface, the steel hooks engage with asperities and holes on the surface. The suspensions allow for individual hooks to engage with asperities while the remaining hooks continue to drag along the surface. This ensures that the maximum possible number of hooks engage with the surface, thereby increasing the load-bearing abilities of the gripper. Using the microspine array grippers described above as the end-effectors of a robot would allow it to traverse terrain previously unreachable by traditional wheeled robots. Furthermore, microspine-gripping robots that can perch on cliffs or rocky walls could enable a new class of persistent surveillance devices for military applications. In order to interface these microspine grippers with a legged robot, an ankle is needed that can robotically actuate the gripper, as well as allow it to conform to the large-scale irregularities in the rock. The anchor serves three main purposes: deploy and release the anchor, conform to roughness or misalignment with the surface, and cancel out any moments about the anchor that could cause unintentional detachment. The ankle design contains a
Field investigation of potential contamination by bitumen-coated piles
International Nuclear Information System (INIS)
Coating piles with bitumen down to their neutral points to debond them from embedding soil is a feasible method to minimize the adverse effects of negative skin friction. Bitumen is a petroleum product composed of numerous extremely complex organic compounds including polycyclic aromatic hydrocarbons (PAHs) that have been identified by the US Environmental Protection Agency (EPA) as toxic and carcinogenic materials. To investigate the engineering behavior of bitumen-coated piles under extreme weather conditions, full-scale field tests were performed in New Orleans, Louisiana, and Edmonton, Alberta, Canada. Instrumented piles were installed at these sites from 1989 to 1990. This paper presents the results of geoenvironmental field investigations performed at these sites to determine the spatial distribution of target PAHs in the subsurface after the piles had been installed for 2--3 1/2 yr. The findings of the investigation indicate that the subsurface contamination, if there is any, caused by the installation of bitumen-coated piles is well within acceptable limits
Prediction of pile set-up in clays and sands
International Nuclear Information System (INIS)
Increase in pile capacity after initial driving has been well observed in clays and sands over decades. The phenomenon is referred to as pile set-up by geotechnical engineers. More economical pile design may benefit from this time-dependent increase subject to a reliable prediction. Simple empirical relations of the current capacity with the initial capacity and elapse time after driving are available in the literature with different model parameters being suggested for clays and sands, respectively. Nevertheless, appropriateness of the relations and confidence interval of the model parameters are rarely investigated and this hinders the application of these formulae. In this study, a revised single-parameter empirical relation is proposed based on the existing formulae. A comprehensive database from pile field tests data in clayey and sandy ground in the literature is compiled and Bayesian analysis is conducted on both these empirical formulae independently for clays and sands. Bayesian inference allows not only the estimation of the uncertain parameter but also the quantification of the associated uncertainty in the form of probability distribution. This study sheds lights on the confidence interval of the model parameter and it provides designers more reliable prediction of the additional capacity due to pile set-up.
WAVE CURRENT FORCES ON THE PILE GROUP OF BASE FOUNDATION FOR THE EAST SEA BRIDGE, CHINA
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
On the basis of the two structures of the bridge foundation designed for the East Sea Bridge, the wave current forces on four types of oblique piles, the pile group and the single piles at different positions in the pile group considering the effect of the super structures were experimentally investigated. The relationship between the wave current forces and the associated wave parameters, and the comparison of the wave current forces on the pile groups and the single piles were systematically analyzed. The group effectiveness and the reduction coefficient for the wave current forces on the group were examined for engineering design.
Analysis of piles in residual soil from granite considering residual loads
da Fonseca, AV; dos Santos, JA; Esteves, EC; F. Massad
2007-01-01
The paper deals with the analysis of static loading tests carried out in 3 different types of piles: bored piles with temporary casing, continuous flight auger, CFA, piles (bored and CFA piles with circular section - nominal diameter Ø600 mm) and driven piles (with square section - width 350 mm). These piles were installed in the CEFEUP/ISC2 experimental site, located in the Campus of the Faculty of Engineering of the University of Porto (Portugal), in a contact zone between the gneissic rock...
Dynamic performance of concrete undercut anchors for Nuclear Power Plants
International Nuclear Information System (INIS)
Graphical abstract: - Highlights: • Behavior of undercut anchors under dynamic actions simulating earthquakes. • First high frequency load and crack cycling tests on installed concrete anchors ever. • Comprehensive review of anchor qualification for Nuclear Power Plants. - Abstract: Post-installed anchors are widely used for structural and nonstructural connections to concrete. In many countries, concrete anchors used for Nuclear Power Plants have to be qualified to ensure reliable behavior even under extreme conditions. The tests required for qualification of concrete anchors are carried out at quasi-static loading rates well below the rates to be expected for dynamic actions deriving from earthquakes, airplane impacts or explosions. To investigate potentially beneficial effects of high loading rates and cycling frequencies, performance tests on installed undercut anchors were conducted. After introductory notes on anchor technology and a comprehensive literature review, this paper discusses the qualification of anchors for Nuclear Power Plants and the testing carried out to quantify experimentally the effects of dynamic actions on the load–displacement behavior of undercut anchors
Cumulative Damage in Strength-Dominated Collisions of Rocky Asteroids: Rubble Piles and Brick Piles
Housen, Kevin
2009-01-01
Laboratory impact experiments were performed to investigate the conditions that produce large-scale damage in rock targets. Aluminum cylinders (6.3 mm diameter) impacted basalt cylinders (69 mm diameter) at speeds ranging from 0.7 to 2.0 km/s. Diagnostics included measurements of the largest fragment mass, velocities of the largest remnant and large fragments ejected from the periphery of the target, and X-ray computed tomography imaging to inspect some of the impacted targets for internal damage. Significant damage to the target occurred when the kinetic energy per unit target mass exceeded roughly 1/4 of the energy required for catastrophic shattering (where the target is reduced to one-half its original mass). Scaling laws based on a rate-dependent strength were developed that provide a basis for extrapolating the results to larger strength-dominated collisions. The threshold specific energy for widespread damage was found to scale with event size in the same manner as that for catastrophic shattering. Therefore, the factor of four difference between the two thresholds observed in the lab also applies to larger collisions. The scaling laws showed that for a sequence of collisions that are similar in that they produce the same ratio of largest fragment mass to original target mass, the fragment velocities decrease with increasing event size. As a result, rocky asteroids a couple hundred meters in diameter should retain their large ejecta fragments in a jumbled rubble-pile state. For somewhat larger bodies, the ejection velocities are sufficiently low that large fragments are essentially retained in place, possibly forming ordered "brick-pile" structures.
Analysis of Glenoid Inter-anchor Distance with an All-Suture Anchor System
Kramer, Jonathan; Robinson, Sean; Dutton, Pascual; Dickinson, Ephraim; Rodriguez, John Paul; Camisa, William; Leasure, Jeremi M.; Montgomery, William H.
2016-01-01
Objectives: Arthroscopic shoulder stabilization using suture anchors are commonly used techniques. More recently developed all-suture systems employ smaller diameter anchors, which increase repair contact area and allow greater placement density on narrow surfaces such as the glenoid. Our goal is investigate the strength characteristics of various inter-anchor distances in a human glenoid model. Methods: Twelve fresh-frozen human cadaveric glenoids were potted after the labrum was excised. The glenoids were then implanted with 1.4 mm all-suture anchors (Juggerknot, Biomet, Warsaw, IN) at varying inter-anchor distances. Anchors were implanted adjacent to one another or at 2 mm, 3 mm, or 5 mm distances using a template with pre-drilled holes. The glenoids were then underwent single cycle pullout testing using a test frame (Instron 8521, Instron Inc., Norwood, MA). A 5 N preload was applied to the construct and the actuator was driven away from the shoulder at a rate of 12.5mm/s as seen in Figure 1. Force and displacement were collected from the test frame actuator at a rate of 500 Hz. The primary outcomes were failure strength and stiffness. Stiffness was calculated from the initial linear region of the force displacement curve. Failure strength was defined as the first local maximum inflection point in the force displacement curve. Results: During load to fail testing, all but three of the specimens had both anchors pull out of the glenoid. The other mode of failure included one or both of the sutures failing. Stiffness was 13.52 ± 3.8, 17.97 ± 5.02, 17.59 ± 4.65 and 18.95 ± 4.67 N/mm for the adjacent, 2 mm, 3 mm and 5 mm treatment groups as shown Table 1. The adjacent group had a significantly lower stiffness compared to the other treatment groups. Failure strength was 48.68 ± 20.64, 76.16 ± 23.78, 73.19 ± 35.83 and 87.04 ± 34.67 N for the adjacent, 2 mm, 3 mm and 5 mm treatment groups as shown in Table 1. The adjacent group had a significantly lower
Design of Jetty Piles Using Artificial Neural Networks
Directory of Open Access Journals (Sweden)
Yongjei Lee
2014-01-01
Full Text Available To overcome the complication of jetty pile design process, artificial neural networks (ANN are adopted. To generate the training samples for training ANN, finite element (FE analysis was performed 50 times for 50 different design cases. The trained ANN was verified with another FE analysis case and then used as a structural analyzer. The multilayer neural network (MBPNN with two hidden layers was used for ANN. The framework of MBPNN was defined as the input with the lateral forces on the jetty structure and the type of piles and the output with the stress ratio of the piles. The results from the MBPNN agree well with those from FE analysis. Particularly for more complex modes with hundreds of different design cases, the MBPNN would possibly substitute parametric studies with FE analysis saving design time and cost.
Seismic soil-structure interaction of foundations with large piles
International Nuclear Information System (INIS)
In seismic regions with soft soil deposits subjected to ground surface subsidence, there is the necessity to support the weight of constructions on large diameter piles or piers hearing on deep firm strata. To justify the action of these elements working under flexo compression and shear, it is necessary to perform calculations of soil pile interaction from a practical engineering point of view and estimate the order of magnitude of the forces and displacements to which these elements will be subjected during the seismic action assigned to the foundation. In this paper we defined a pier as a large diameter pile constructed on site. Furthermore, in the seismic analysis it is necessary to evaluate the seismic pore water pressure to learn on the effective seismic soil stresses close to the ground surface. (author)
X-ray spectroscopy around the pile-up region
Sharma, Gaurav; Kumar, Basu; Puri, Nitin Kumar; Nandi, Tapan
2015-01-01
We report a pile-up rejection technique based on X-ray absorption concept of Beer-Lambert law for measuring true events in the pile-up region. We have detected a four orders times weaker peak in the pile-up region. This technique also enables one to resolve the weak peaks adjacent to an intense peak provided the latter lies in the lower energy side, and the peaks are at least theoretically resolvable by the detector used. We have resolved such peaks by reducing the intensity ratios in our experiment. The technique allows us to obtain the actual intensities of the observed peaks to have been measured without any attenuator. The possible applications of this technique can be to study the physics of two electron one-photon transition as well as the properties of projectile-like or target-like ions.
Probabilistic Assessment for Seismic Performance of Pile-Supported Wharves
Directory of Open Access Journals (Sweden)
Hamid Heidary Torkamani
2013-03-01
Full Text Available The main objective of this study is to investigate the influence of uncertainties associated with the material properties on the seismic performance of pile-supported wharves. For this purpose a two-dimensional finite difference model, representing typical pile-supported wharf structures from western United States has been constructed using software FLAC2D. Incremental dynamic analysis has been applied to evaluate the response of wharf structure under different levels of seismic loading. The uncertainties at both structural and geotechnical parameters have been investigated using a tornado diagram and a ﬁrst-Order Second-Moment (FOSM analysis. It has been found that the uncertainties at the dead load of structure, friction angle of rock fill and the porosity of rock fill contribute most to the variability of the displacement ductility factor of the pile-supported wharf structures. Based on the results, design considerations have been provided.
The Strength of Regolith and Rubble Pile Asteroids
Sánchez, Paul
2013-01-01
We explore the hypothesis that, due to small van der Waals forces between regolith grains, the strength of small rubble pile asteroids is constant. This creates a scale dependence, with relative strength increasing as size decreases. This counters classical theory that rubble pile asteroids should behave as scale-independent cohesionless collections of rocks. We explore a simple model for asteroid strength that is based on these weak forces, validate it through granular mechanics simulations and comparisons with properties of lunar regolith, and then show its implications and ability to explain and predict observed properties of small asteroids in the NEA and Main Belt populations. A conclusion is that the population of rapidly rotating asteroids consists of both distributions of smaller grains (i.e., rubble piles) and of monolithic boulders whose surfaces may still retain a size distribution of finer grains, potentially of size up to centimeters.
Improved Design Basis for Laterally Loaded Large Diameter Pile
DEFF Research Database (Denmark)
Leth, Caspar Thrane
the structure and the productivity of the turbine. Current design practice for monopiles are based on p-y curves developed for slender piles with a diameter of 0.6 m. The focus on the structure stiffness has entailed a significant research on the soil-structure interaction for large diameter monopiles...... diameter, depth and soil strength, and increase of each these will give an increase in stiffness. • Cyclic response of a lateral loaded pile is depended on the characteristics of the cyclic load. Behaviour of a monopile is a classic soil-structure interaction problem depending on the pile stiffness and the...... expected development of offshore wind farms is towards larger farms, larger turbines and larger water depths. Monopiles have been applied widely and it is of interest to investigate the possibilities to further optimize the design and in particular the modelling of the soil-structure interaction. The...
Ground Vibration Isolation of Multiple Scattering by Using Rows of Tubular Piles as Barriers
Directory of Open Access Journals (Sweden)
Miao-miao Sun
2014-01-01
Full Text Available A new formal solution for the multiple scattering of plane harmonic waves by a group of arbitrary configuration tubular piles in an elastic total space is derived. Each order of scattering satisfies prescribed boundary conditions at the interface of tubular piles, which is delivered as the sum of incident and scattering waves. The first order performs the scattering wave by each scattered pile and the subsequent orders resulted from the excitation of each pile of first order of scattering from the remaining tubular piles. Advanced scattering orders can be regarded as the same manners. Several series of scattering coefficients are figured out with the aids of addition theorem so that the exact steady-state solution for the scattered displacement and stress is obtained. Particularly, when internal diameter of tubular piles tends to be infinitely small, it degenerates to a solid pile problem. By imposing the normalized displacement amplitudes and transmissibility indices, the influences of specific parameters such as scattering orders, internal and external diameter ratio of piles, pile material rigidity, position and distances between tubular pile and pile rows, and pile numbers are discussed. Certain recommended conclusions have been drawn as the guidelines of practical engineering design for discontinuous barrier of tubular piles.
Target reliability index for serviceability limit state of single piles
Institute of Scientific and Technical Information of China (English)
边晓亚; 郑俊杰; 徐志军; 章荣军
2015-01-01
The objective is to develop an approach for the determination of the target reliability index for serviceability limit state (SLS) of single piles. This contributes to conducting the SLS reliability-based design (RBD) of piles. Based on a two-parameter, hyperbolic curve-fitting equation describing the load−settlement relation of piles, the SLS model factor is defined. Then, taking into account the uncertainties of load−settlement model, load and bearing capacity of piles, the formula for computing the SLS reliability index (βsls) is obtained using the mean value first order second moment (MVFOSM) method. Meanwhile, the limit state function for conducting the SLS reliability analysis by the Monte Carlo simulation (MCS) method is established. These two methods are finally applied to determine the SLS target reliability index. Herein, the limiting tolerable settlement (slt) is treated as a random variable. For illustration, four load test databases from South Africa are compiled again to conduct reliability analysis and present the recommended target reliability indices. The results indicate that the MVFOSM method overestimatesβsls compared to that computed by the MCS method. Besides, both factor of safety (FS) and slt are key factors influencingβsls, so the combination of FS andβsls is welcome to be used for the SLS reliability analysis of piles when slt is determined. For smaller slt, pile types and soils conditions have significant influence on the SLS target reliability indices; for larger slt, slt is the major factor having influence on the SLS target reliability indices. This proves that slt is the most key parameter for the determination of the SLS target reliability index.
Assessment of Time Functions for Piles Driven in Clay
DEFF Research Database (Denmark)
Augustesen, Anders; Andersen, Lars; Sørensen, Carsten Steen
The vertical bearing capacity of piles situated in clay is studied with regard to the long-term set-up. A statistical analysis is carried out on the basis of data from numerous static loading tests. The database covers a wide range of both soil and pile properties, which ensures a general...... alternative models. In the first of these models, the rate of set-up is independent of the soil properties, whereas the second function depends on the undrained shear strength. Based on the available data, there is no statistical evidence that the magnitude of set-up depends on the properties of the soil...
Testing of Laterally Loaded Rigid Piles with Applied Overburden Pressure
DEFF Research Database (Denmark)
Sørensen, Søren Peder Hyldal; Foglia, Aligi; Ibsen, Lars Bo
2012-01-01
Small-scale tests have been conducted for the purpose of investigating the quasi-static behaviour of laterally loaded, non-slender piles installed in cohesionless soil. For that purpose, a new and innovative test setup has been developed. The tests have been conducted in a pressure tank such that...... it was possible to apply an overburden pressure to the soil. Hereby, the traditional uncertainties related to low effective stresses for small-scale tests has been avoided. A scaling law for laterally loaded piles has been proposed based on dimensional analysis. The novel testing method has been...... validated against the test results by means of the scaling law....
Testing of Laterally Loaded Rigid Piles with Applied Overburden Pressure
DEFF Research Database (Denmark)
Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Foglia, Aligi
2015-01-01
Small-scale tests have been conducted to investigate the quasi-static behaviour of laterally loaded, non-slender piles installed in cohesionless soil. For that purpose, a new and innovative test setup has been developed. The tests have been conducted in a pressure tank such that it was possible to...... apply an overburden pressure to the soil. As a result of that, the traditional uncertainties related to low effective stresses for small-scale tests have been avoided. A normalisation criterion for laterally loaded piles has been proposed based on dimensional analysis. The test results using the novel...... testing method have been compared with the use of the normalisation criterion....
Golden Herbs used in Piles Treatment: A Concise Report
Directory of Open Access Journals (Sweden)
Rajani Chauhan
2012-12-01
Full Text Available Herbal medicine is also called phytomedicine. It is refers to using a plant's seeds, berries, roots, leaves, bark, or flowers for disease treatment.Herbs have many golden phytochemicals or secondary metabolites to treat disease. They have a long tradition of use outside of conventional medicine. Hemorrhoids or Piles treatment through Herbs has been effective and a golden treatment without any side-effects. There are some herbs which is useful in piles treatment such as Aesculus hippocastanum, Allium cepa, Bergenia ligulata, Bergenia ciliata, Bergenia stracheyi, Hamamelis virginiana Ruscus aculeatus, Terminalia chebula Vaccinium myrtillus, Verbascum thapus etc.
Centrifuge modelling of a laterally cyclic loaded pile
DEFF Research Database (Denmark)
Klinkvort, Rasmus Tofte; Leth, Caspar Thrane; Hededal, Ole
A total number of 9 static and 6 cyclic centrifuge tests on laterally loaded piles in very dense, dry sand was erformed. The prototype dimensions of the piles were 1 meter in diameter and penetration depths varying from 6 to 10 meters. The static tests were used to investigate the initial subgrade...... reaction modulus and as a reference for cyclic tests. For the cyclic tests the accumulation of deflections and the change in secant stiffness of the soil from repetitive loading were investigated. From all the tests carried out accumulations of deflections were seen. rom the centrifuge tests it was seen...
Collapse mechanisms and strength prediction of reinforced concrete pile caps
DEFF Research Database (Denmark)
Jensen, Uffe G.; Hoang, Linh Cao
2012-01-01
This paper describes an upper bound plasticity approach for strength prediction of reinforced concrete pile caps. A number of collapse mechanisms are identified and analysed. The procedure leads to an estimate of the load-carrying capacity and an identification of the critical collapse mechanism....... Calculations have been compared with nearly 200 test results found in the literature. Satisfactory agreement has been found. The analyses are conducted on concentrically loaded caps supported by four piles. The paper briefly outlines how the approach may be extended to more complicated loadings and geometries...
Anchoring of FRET Sensors-A Requirement for Spatiotemporal Resolution.
Ivanova, Elena V; Figueroa, Ricardo A; Gatsinzi, Tom; Hallberg, Einar; Iverfeldt, Kerstin
2016-01-01
FRET biosensors have become a routine tool for investigating mechanisms and components of cell signaling. Strategies for improving them for particular applications are continuously sought. One important aspect to consider when designing FRET probes is the dynamic distribution and propagation of signals within living cells. We have addressed this issue by directly comparing an anchored (taFS) to a non-anchored (naFS) cleavable FRET sensor. We chose a microtubule-associated protein tau as an anchor, as microtubules are abundant throughout the cytosol of cells. We show that tau-anchored FRET sensors are concentrated at the cytoskeleton and enriched in the neurite-like processes of cells, providing high intensity of the total signal. In addition, anchoring limits the diffusion of the sensor, enabling spatiotemporally resolved monitoring of subcellular variations in enzyme activity. Thus, anchoring is an important aspect to consider when designing FRET sensors for deeper understanding of cell signaling. PMID:27196902
Adsorption phenomena and anchoring energy in nematic liquid crystals
Barbero, Giovanni
2005-01-01
Despite the large quantity of phenomenological information concerning the bulk properties of nematic phase liquid crystals, little is understood about the origin of the surface energy, particularly the surface, interfacial, and anchoring properties of liquid crystals that affect the performance of liquid crystal devices. Self-contained and unique, Adsorption Phenomena and Anchoring Energy in Nematic Liquid Crystals provides an account of new and established results spanning three decades of research into the problems of anchoring energy and adsorption phenomena in liquid crystals.The book contains a detailed discussion of the origin and possible sources of anchoring energy in nematic liquid crystals, emphasizing the dielectric contribution to the anchoring energy in particular. Beginning with fundamental surface and anchoring properties of liquid crystals and the definition of the nematic phase, the authors explain how selective ion adsorption, dielectric energy density, thickness dependence, and bias voltage...
Anchor Toolkit - a secure mobile agent system
Energy Technology Data Exchange (ETDEWEB)
Mudumbai, Srilekha S.; Johnston, William; Essiari, Abdelilah
1999-05-19
Mobile agent technology facilitates intelligent operation insoftware systems with less human interaction. Major challenge todeployment of mobile agents include secure transmission of agents andpreventing unauthorized access to resources between interacting systems,as either hosts, or agents, or both can act maliciously. The Anchortoolkit, designed by LBNL, handles the transmission and secure managementof mobile agents in a heterogeneous distributed computing environment. Itprovides users with the option of incorporating their security managers.This paper concentrates on the architecture, features, access control anddeployment of Anchor toolkit. Application of this toolkit in a securedistributed CVS environment is discussed as a case study.
Starting point anchoring effects in choice experiments
DEFF Research Database (Denmark)
Ladenburg, Jacob; Olsen, Søren Bøye
Anchoring is acknowledged as a potential source of considerable bias in Dichotomous Choice Contingent Valuation studies. Recently, another stated preference method known as Choice Experiments has gained in popularity as well as the number of applied studies. However, as the elicitation of...... subjectivity in the present study is gender dependent, pointing towards, that female respondents are prone to be affected by the price levels employed. Male respondents, on the other hand, are not sensitive towards these prices levels. Overall, this implicates that female respondents, when employing a low...
DEFF Research Database (Denmark)
Foghsgaard, Søren
2014-01-01
The bone-anchored hearing aid (Baha) was introduced in 1977 by Tjellström and colleagues and has now been used clinically for over 30 years. Generally, the outcomes are good, and several studies have shown improved audiological- and quality of life outcomes. The principle of the Baha is, that sound...... vibrations are led directly to the inner ear via the mastoid bone, bypassing the middle ear. This is achieved via an osseointegrated implant and a skin-penetrating abutment. Studies report high success rates and a majority of complications as typically minor in nature....
Institute of Scientific and Technical Information of China (English)
Wang Teng; Wang Kuihua; Xie Kanghe
2001-01-01
The vibration problem of a pile of arbitrary segments with variable modulus under exciting force is established, in which the influence of the soil under pile toe and the surroundings is taken into account. With Laplace transforms, the transmit functions for velocity and displacement of pile are derived. Furthermore, in terms of the convolution theorem and inversed Laplace transform, an analytical solution for the time domain response of a pile subjected to a semi-sine impulse is developed,which is the theoretical basis of the sonic method in pile integrity testing. Based on the solution, the vibration properties of pile with sharp or continuous modulus are studied. The validity of this approach is verified through fidd dynamic tests on some engineering piles. It shows that the theoretical prediction and the response of the pile are in good agreement.
Dynamic stiffness of pile groups in a multilayered soil. Part 1
International Nuclear Information System (INIS)
For evaluating the dynamic stiffness of the pile group foundations, forced vibration tests are executed on pile group foundation models. Two types of test models are used, one is a single pile model and the other a four-pile model. Dividing the tests into 4 steps, the forced vibration tests are performed. Step 1 is for the single pile model, and steps 2 to 4 are for the four-pile model. In step 2 and step 3, the gap effects between the foundation bottom and the ground surface are examined. In step 4, the backfill effects are obtained. Based on the test results, the pile group effects, the gap effects and the backfill effects on the dynamic characteristics of the pile group foundations are described in this paper
Numerical Analysis of Interaction Between Pile-Supported Pier and Bank Slope
Institute of Scientific and Technical Information of China (English)
王年香
2001-01-01
Two- and three-dimensional finite element analysis programs for pile-soil interaction are compiled. Duncan-Chang's Model is used. The construction sequence of the pier is modeled. The pile-soil interface element is used. The influence of the combination type of piles on the deformation of bank slope and pile behaviour is analyzed. Different designs of a pile-supported pier are compared thoroughly. Calculation results show that the stresses and displacements of the pile are directly related to the distance from the bank slope and the direction of inclination. An inclined prop pile set in the rear platform would remarkably reduce the stresses of piles and the displacement of the pier.
Difficulties and measures of driving super long piles in Bohai Gulf
Directory of Open Access Journals (Sweden)
Shuwang Yan
2015-03-01
Full Text Available Long piles of the ocean oil platform are usually manufactured as the integration of several segments, which have to be assembled one by one during installation. During pile driving, excessive pore pressure will build up in such a high level that hydraulic fracturing in the soil round the pile may take place, which will cause the soil to consolidate much faster during pile extension period. Consequently, after pile extension, the soil strength will recover to some extent and the driving resistance will increase considerably, which makes restarting driving the pile very difficult and even causes refusal. A finite element (FE analysis procedure is presented for judging the risk of refusal by estimating the blow counts after pile extension, in which the regain of soil strength is considered. A case analysis in Bohai Gulf is performed using the proposed procedure to explain the pile refusal phenomenon.
Experimental study on DX pile performance in frozen soils under lateral loading
Institute of Scientific and Technical Information of China (English)
XiaoBing Liu; LiHong Chen; ZhongYang Yu; JianXiao Hu; Wen Peng
2013-01-01
Experiments about working mechanism and mechanical characteristics of the DX model pile foundation under lateral dynamic and static loading were conducted by using a model system of the dynamic frozen soil-pile interaction. The horizontal displacement-force relationship of the pile head and bending moment distribution along the body in frozen soils of different temperatures were discussed. According to test results, both the horizontal displacement-force relationship of the DX pile head and bending moment distribution of the DX pile body are smaller than that of equal-diameter piles under same lateral loads. The piles with different plate positions show different displacements and bending moments. This phenomenon is mainly related to the soil temperature and bearing plates locations. Thus, dynamic response analysis of the pile foundation should be taken into account.
Nominal Anchor Exchange Rate Policies as a Domestic Distortion
Anne O. Krueger
1997-01-01
This paper analyzes a nominal anchor exchange rate policy as a domestic distortion, in the tradition of international trade theory. It is shown that, in addition to the problems of sustainability and exit pinpointed in the exchange rate literature, a nominal anchor exchange rate policy, while in force, drives a wedge between the domestic and the international intertemporal marginal rates of substitution. The welfare cost of the Mexican use of the nominal anchor exchange rate policy prior to D...
The impact of anchoring bias in the UK equity market
Koskinen, Matti
2013-01-01
PURPOSE OF THE STUDY The purpose of this thesis is to study how the anchoring bias, a cognitive bias, affects equity analysts' forecasts and what kind of implications this bias has for investors and managers of listed companies in the UK stock market. I test whether industry median forecast earnings per share can work as an anchor when analysts are estimating companies' future earnings and how this potential anchoring affects forecast errors, future stock returns, earnings surprises and s...
Decoding Cytoskeleton-Anchored and Non-Anchored Receptors from Single-Cell Adhesion Force Data.
Sariisik, Ediz; Popov, Cvetan; Müller, Jochen P; Docheva, Denitsa; Clausen-Schaumann, Hauke; Benoit, Martin
2015-10-01
Complementary to parameters established for cell-adhesion force curve analysis, we evaluated the slope before a force step together with the distance from the surface at which the step occurs and visualized the result in a two-dimensional density plot. This new tool allows detachment steps of long membrane tethers to be distinguished from shorter jumplike force steps, which are typical for cytoskeleton-anchored bonds. A prostate cancer cell line (PC3) immobilized on an atomic-force-microscopy sensor interacted with three different substrates: collagen-I (Col-I), bovine serum albumin, and a monolayer of bone marrow-derived stem cells (SCP1). To address PC3 cells' predominant Col-I binding molecules, an antibody-blocking β1-integrin was used. Untreated PC3 cells on Col-I or SCP1 cells, which express Col-I, predominantly showed jumps in their force curves, while PC3 cells on bovine-serum-albumin- and antibody-treated PC3 cells showed long membrane tethers. The probability density plots thus revealed that β1-integrin-specific interactions are predominately anchored to the cytoskeleton, while the nonspecific interactions are mainly membrane-anchored. Experiments with latrunculin-A-treated PC3 cells corroborated these observations. The plots thus reveal details of the anchoring of bonds to the cell and provide a better understanding of receptor-ligand interactions. PMID:26445433
Studying and Preparing of Basic Time for Piling Works by Synthetic Equations
Naiyakeat Pongpatanasuegsa; Wisoot Jiradamkerng; Supa Thongmai
2011-01-01
The objective of this research is to study and prepare basic time for piling works by synthetic equations. The time data of 7 work elements of piling works were collected from 10 different construction sites in Phuket Province of Thailand. The synthetic equations were derived with multiple regressions analysis method using statistic software package. These work elements consisted of pile driving work , moving piling rig left or right on supporting rails , moving supporting rails left or right...
Cyclic and Rapid Axial Load Tests on Displacement Piles in Soft Clay
Doherty, Paul; Gavin, Kenneth
2012-01-01
Offshore piles are subjected to complex loading regimes, which include both rapidly applied static and cyclic loads. This note describes an experimental investigation conducted in order to assess the factors influencing the response of offshore piles to these loading conditions. The tests were performed using instrumented model piles installed in soft clay. During cyclic loading, the piles demonstrated a transition from stable to unstable behaviour when the applied loads reache...
Comparative Model Tests of SDP and CFA Pile Groups in Non-Cohesive Soil
Krasiński Adam; Kusio Tomasz
2015-01-01
The research topic relates to the subject of deep foundations supported on continuous flight auger (CFA) piles and screw displacement piles (SDP). The authors have decided to conduct model tests of foundations supported on the group of piles mentioned above and also the tests of the same piles working as a single. The tests are ongoing in Geotechnical Laboratory of Gdaňsk University of Technology. The description of test procedure, interpretation and analysis of the preliminary testing series...
Three dimensional numerical modelling of rows of discrete piles used to stabilise large landslides
Kanagasabai, Sasokanthan
2010-01-01
A number of three dimensional finite difference analyses using FLAC3D have been carried out to investigate the complex pile-soil interaction effects of single isolated pile and groups of piles. The three-dimensional numerical models developed to carry out these analyses are able to model the full pile-soil interaction problem including three dimensional and surface effects which cannot be understood fully using two dimensional analyses. FLAC3D analyses are initially carried out to investigate...
Influence of Pile-Pier Reinforcement Ratio on the Development of Plastic Zone of Bridge Structure
Song Bo; Li, Kaiwen; Zhong Min
2013-01-01
In this study, using elastic-plastic fiber unit model for a continuous beam bridge structure and foundation to analyses the nonlinear seismic response of pier and pile foundation considering pile-soil interaction and the different types of seismic wave on the pile foundation and the pier’ dynamic response, focusing on the development of plastic zone and dynamic response of structure under different pile-pier reinforcement ration conditions. The results show...
Static Test and Result Analysis on Different Types of Pile Composite Foundation in the Same Field
Directory of Open Access Journals (Sweden)
Zhao Tuo
2015-01-01
Full Text Available Combining with the situation of soil test site, the large scale experiment was studying about natural foundation, rammed soil-cement piles, CFG pile and gravel pil. A series of conclusions were given from p-s curve, the fitting curve, and the Angle of the stress ratio of pile-soil composite modulus. It has certain guiding significance for the design and construction of pile type, which is used in North China area.
Static nonlinear analysis of piles cap based on the Continuum Damage Mechanics
Luiz Antonio Farani de Souza
2015-01-01
The piles cap is an important structural element whose function is to transfer the actions of the superstructure for a group of piles. The visual inspection of the piles cap behavior under service conditions is not possible and, in addition, the knowledge of its actual structural performance is a vital necessity for the constructions overall stability. In this paper, a two-dimensional nonlinear analysis is carried out, by means of Finite Element Method, of a reinforced concrete pile caps with...
Illusion of Relevance: Anchoring in Economic and Financial Knowledge
Directory of Open Access Journals (Sweden)
Andrey Kudryavtse
2010-12-01
Full Text Available Contemporary research documents various psychological aspects of economic thought and decision-making. The main goal of our study is to analyze the role of the anchoring (bias(Tversky and Kahneman, 1974 in perceiving economic and financial information, and, in particular, the effect of perceived relevance of the anchors on the degree of the bias. Anchoring bias refers to people's tendency to form their estimates for different categories, starting from a particular available, and often irrelevant, value and insufficiently adjusting their final judgments from this starting value. We carry out an experiment involving a group of MBA students, asking them to recall a number of recent economic and financial indicators (stock and bond market index returns, rates of inflation, currency exchange rates, etc., with half of the participants receiving actual information about some unrelated indicators (anchors, before answering the questions. We document that significant anchoring bias is exhibited, on average, for each of our experimental questions and by vast majority of the participants, the degree of the bias being higher for women and older participants. Furthermore, in the context of the effect of anchors' perceived relevance, we find that people exhibit significantly stronger bias in cases when the anchor is presented as a similar category. Our findings indicate that if, at least at the first glance, an anchor bears some similarity to the target question, then the resulting answer may be more assimilated towards the anchor
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Two full-scale experiments using controlled blasting were conducted in the Port of Tokachi on Hokkaido Island,Japan, to assess the behavior of piles and pipelines subjected to lateral spreading. Test specimens were extensively instrumented with strain gauges to measure the distribution of moment during lateral spreading. This allowed us to compute the loading condition, as well as to conduct damage and performance assessments on the piles and pipelines. This paper presents the test results and discussions on the response of single piles and pipelines observed from the full-scale experiments. Based on the test results, it can be concluded that using controlled blasting successfully liquefied the soil, and subsequently induced lateral spreading. The movements of the single pile, as well as the transverse pipelines, were approximately the same as the free field soil movement. Observed moment distribution of the single pile indicated that global translation of the liquefied soil layer provided insignificant force to the pile. In addition, the degree of fixity at the pile tip significantly affected the moment along the pile as well as the pile head displacement. The pile with a higher degree of fixity at the pile tip had smaller pile head displacement but larger maximum moment.
Jansen, H.W.; Jong, C.A.F. de; Jung, B.
2012-01-01
Because of the concern about potential effects on marine pile driving, the industry is developing silent marine pile driving concepts. One of the new concepts, which has been engineered by IHC Hydrohammer in the Netherlands, is the application of a steel Noise Mitigation Screen (NMS) around the pile
Experimental Investigations of Tension Piles in Sand Subjected to Static and Cyclic Loading
DEFF Research Database (Denmark)
Thomassen, Kristina
The present thesis regards the behavior of the piles in jacket pile foundations used for offshore wind turbines. The piles are often loaded in tension because of the combination of wind and wave conditions and the low self-weight of the wind turbine. The repeated cyclic loading can lead to...
The Underwater Sound Field from Impact Pile Driving and Its Potential Effects on Marine Life
Dahl, P.H.; Jong, C.A.F. de; Popper, A.N.
2015-01-01
Impact pile driving is a method used to install piles for marine and inland water construction projects using high-energy impact hammers. The installation of hollow steel piles in this manner can produce extremely high sound levels in the surrounding waters (as well as in the air). Given the large-
The effect of the timing of pile mixing on greenhouse gas (GHG) emissions during dairy manure composting was determined using large flux chambers designed to completely cover replicate pilot-scale compost piles. GHG emissions from compost piles that were mixed at 2, 3, 4, or 5 weeks after initial c...
40 CFR 411.30 - Applicability; description of the materials storage piles runoff subcategory.
2010-07-01
... materials storage piles runoff subcategory. 411.30 Section 411.30 Protection of Environment ENVIRONMENTAL... Materials Storage Piles Runoff Subcategory § 411.30 Applicability; description of the materials storage piles runoff subcategory. The provisions of this subpart are applicable to discharges resulting from...
Energy Technology Data Exchange (ETDEWEB)
Furet, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1962-07-01
A brief survey is first given of the general theorems of Boodle's algebra and of sequence systems using D.A. Huffmans theory. Some indications are then given concerning the setting-up and the operation of digital computers and also of the principal codes used in digital techniques. It is then shown how digitalisation in atomic pile control makes it possible to use new techniques having the following advantages in particular: greater working safety, a higher degree of centralisation, and suppression of the linear elements. A few examples are given of the application of these techniques to control, particularly with respect to the measurement of the neutronic power and of the period and also of course, to the treatment of the data and the sequence automatisms. The advantage of using digital techniques in the shutdown channels is also examined. Finally a review is given of the technology and the viability of the control devices used. (author) [French] On rappelle d'abord ici les theoremes generaux de l'algebre de Boole et des systemes a sequences en s'appuyant sur la theorie de D.A. Huffmann. On donne ensuite quelques indications sur l'agencement et le fonctionnement des calculateurs digitaux ainsi que les principaux codes utilises dans les techniques digitales. On montre alors comment la digitalisation dans le controle des piles atomiques permet d'utiliser de nouvelles techniques presentant principalement les avantages suivants: securite de fonctionnement plus grande, centralisation plus elevee et suppression des elements lineaires. Un certain nombre d'exemples sont donnes sur l'application de ces techniques au controle, particulierement en ce qui concerne la mesure de la puissance neutronique, de la periode et aussi bien entendu du traitement des informations et des automatismes a sequences. On analyse aussi l'avantage de l'utilisation des techniques digitales dans les chaines de securite. Enfin, un apercu est donne
Centrifuge modelling of rigid piles in soft clay
DEFF Research Database (Denmark)
Klinkvort, R.T.; Poder, M.; Truong, P.;
2016-01-01
this study is to employ centrifuge modelling in order to derive experimental p-y curves for rigid piles embedded in over-consolidated soft clay. A kaolin clay sample was prepared and pre-consolidated by applying a constant pressure at the soil surface, while different over-consolidation ratios were...
Laboratory Testing of Cyclic Laterally Loaded Pile in Cohesionless Soil
DEFF Research Database (Denmark)
Roesen, Hanne Ravn; Ibsen, Lars Bo; Hansen, Mette;
2013-01-01
serviceability limit state. In this paper small-scale testing of a pile subjected to cyclic, lateral loading is treated in order to investigate the effect of cyclic loading. The test setup, which is an improvement of a previous setup, is described and the first results of testing are compared with previous...
Physical Modelling of Cyclic Laterally Loaded Pile in Cohesionless Soil
DEFF Research Database (Denmark)
Hansen, Mette; Wolf, Torben K.; Rasmussen, Kristian L.;
serviceability limit state. In this paper small-scale testing of a pile subjected to cyclic, lateral loading is treated in order to investigate the effect of cyclic loading. The test setup, which is an improvement of a previous setup, is described and the first results of testing are compared with previous...
Calibration of Partial Factors for Basal Reinforced Piled Embankments
Van Duijnen, P.G.; Schweckendiek, T.; Calle, E.O.F.; Van Eekelen, S.J.M.
2015-01-01
In the Netherlands, the design guideline for basal reinforced piled embankments has been revised (CUR226:2015) adopting a new analytical design model (The Concentric Arches (CA) model, Van Eekelen et al., 2013; 2015). The CA model provides geosynthetic reinforcement (GR) strains which were compared
Vision-based autonomous grasping of unknown piled objects
International Nuclear Information System (INIS)
Computer vision techniques have been used to develop a vision-based grasping capability for autonomously picking and placing unknown piled objects. This work is currently being applied to the problem of hazardous waste sorting in support of the Department of Energy's Mixed Waste Operations Program
Airborne sound propagation over sea during offshore wind farm piling.
Van Renterghem, T; Botteldooren, D; Dekoninck, L
2014-02-01
Offshore piling for wind farm construction has attracted a lot of attention in recent years due to the extremely high noise emission levels associated with such operations. While underwater noise levels were shown to be harmful for the marine biology, the propagation of airborne piling noise over sea has not been studied in detail before. In this study, detailed numerical calculations have been performed with the Green's Function Parabolic Equation (GFPE) method to estimate noise levels up to a distance of 10 km. Measured noise emission levels during piling of pinpiles for a jacket-foundation wind turbine were assessed and used together with combinations of the sea surface state and idealized vertical sound speed profiles (downwind sound propagation). Effective impedances were found and used to represent non-flat sea surfaces at low-wind sea states 2, 3, and 4. Calculations show that scattering by a rough sea surface, which decreases sound pressure levels, exceeds refractive effects, which increase sound pressure levels under downwind conditions. This suggests that the presence of wind, even when blowing downwind to potential receivers, is beneficial to increase the attenuation of piling sound over the sea. A fully flat sea surface therefore represents a worst-case scenario. PMID:25234870
20051655 - Petronas, Capacity of Driven Piles Offshore Malaysia
DEFF Research Database (Denmark)
Augustesen, Anders
This document is one of four notes concerning the effects of time (in this case ageing) on the vertical capacity of piles. It includes summaries of relevant publications related to the topic. Further, focus has been paid to publications that deal with quantification of setup and not the mechanism...
20051655 - Petronas, Capacity of Driven Piles Offshore Malaysia
DEFF Research Database (Denmark)
Augustesen, Anders
This report presents the results of work carried out by Aalborg Univesity for NGI related to the effects of ageing on the axial capacity of piles in clay and sand. The document is the fourth of four notes regarding the subject and it includes a recommended approach to account for ageing effects f...
Behavior of Pile Group with Elevated Cap Subjected to Cyclic Lateral Loads
Institute of Scientific and Technical Information of China (English)
陈云敏; 顾明; 陈仁朋; 孔令刚; 张浙杭; 边学成
2015-01-01
The pile group with elevated cap is widely used as foundation of offshore structures such as turbines, power transmission towers and bridge piers, and understanding its behavior under cyclic lateral loads induced by waves, tide water and winds, is of great importance to designing. A large-scale model test on 3×3 pile group with elevated cap subjected to cyclic lateral loads was performed in saturated silts. The preparation and implementation of the test is presented. Steel pipes with the outer diameter of 114 mm, thickness of 4.5 mm, and length of 6 m were employed as model piles. The pile group was cyclic loaded in a multi-stage sequence with the lateral displacement controlled. In addition, a single pile test was also conducted at the same site for comparison. The displacement of the pile cap, the internal forces of individual piles, and the horizontal stiffness of the pile group are presented and discussed in detail. The results indicate that the lateral cyclic loads have a greater impact on pile group than that on a single pile, and give rise to the significant plastic strain in the soil around piles. The lateral loads carried by each row of piles within the group would be redistributed with loading cycles. The lateral stiffness of the pile group decreases gradually with cycles and broadly presents three different degradation patterns in the test. Significant axial forces were measured out in some piles within the group, owing to the strong restraint provided by the cap, and finally lead to a large settlement of the pile group. These findings can be referred for foundation designing of offshore structures.
Experimental Research on Large Diameter Cast-in-Place Piles Embedded in Rock
Institute of Scientific and Technical Information of China (English)
衡朝阳; 何满潮; 姚爱军
2001-01-01
This paper expatiated the field test of large diameter cast-in-place piles embedded in soft rock, including static loading test, high or low strain dynamic test, measurement of stresses and strains of pile body, and pressure measurements between pile tip and soft rock. The relative in-situ test problems are discussed. Based on the limit equilibrium theory and the load transfer equation, a synthesis method of analyzing the ultimate carrying capacity of single large diameter pile is put forward. The research results show that the key to determining the ultimate carrying capacity of single pile with a large diameter is the analysis of the intensity of soft rock.
The thermal behaviour of three different auger pressure grouted piles used as heat exchangers
Loveridge, F.; Olgun, C.G.; Brettmann, T.; Powrie, W.
2014-01-01
Three auger pressure grouted (APG) test piles were constructed at a site in Richmond, Texas. The piles were each equipped with two U-loops of heat transfer pipes so that they could function as pile heat exchangers. The piles were of two different diameters and used two different grouts, a standard APG grout and a thermally enhanced grout. Thermal response tests, where fluid heated at a constant rate is circulated through the pipe loops, were carried out on the three piles, utilising either ...
Finite Element Investigations on the Interaction between a Pile and Swelling Clay
Kaufmann, Kristine Lee; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust
2010-01-01
This paper aims to investigate the interaction between a pile and a swelling soil modelled as a cohesive soil subjected to unloading. The investigations include analyses of the heave of the excavation level, shear stresses at the soil–pile interface and internal pile forces based on a case study of Little Belt Clay. The case study involves a circular concrete pile installed in clay immediately after an excavation. The influence of the swelling soil on the soil–pile interaction and the interna...
Experimental Study on Post Grouting Bearing Capacity of Large Diameter Bored Piles
Wang Duanduan; Wang Longfei; Zhang Lipeng
2015-01-01
Post grouting can improve the inherent defects such as the formation of the mud cake at pile side and the sediment at pile end in the process of bored pile construction. Thus post grouting has been widely used in Engineering. The purpose of this paper is to research the influences of post grouting to pile bearing capacity more systematically and intuitively. Combined with the static load test of four test piles in Weihe River Bridge test area of new airport highway in Xi’an, the bearing capac...
Experimental analysis of the inertial soil-pile interaction in the centrifuge
CHENAF, N; CHAZELAS, JL; Escoffier, S.
2006-01-01
The soil-pile dynamic interaction is studied through centrifuge tests. In this paper, we focus on the inertial effect as a first step to knowledge the seismic behaviour of the soil-pile system. A single shock test, applied at the head of a flexible single pile, is used to simulate an impact on bridge piers ; successive shocks are also used to simulate boat impacts on harbour facilities. To improve the understanding of the inertial soil-pile interaction, a comparison of pile response to both l...
30 CFR 57.9311 - Anchoring stationary sizing devices.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Anchoring stationary sizing devices. 57.9311 Section 57.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 57.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing...
30 CFR 56.9311 - Anchoring stationary sizing devices.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Anchoring stationary sizing devices. 56.9311 Section 56.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 56.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing...
Understanding Rasch Measurement: Partial Credit Model and Pivot Anchoring.
Bode, Rita K.
2001-01-01
Describes the Rasch measurement partial credit model, what it is, how it differs from other Rasch models, and when and how to use it. Also describes the calibration of instruments with increasingly complex items. Explains pivot anchoring and illustrates its use and describes the effect of pivot anchoring on step calibrations, item hierarchy, and…
Zhao Feng
2015-01-01
The slurry wall bored grouting has some defects. The pile-base post grouting technique can efficiently make up these defects and greatly improve the bearing capacity. Based on the pile-base post grouting technique and its process analysis, this paper carries out a detailed analysis about the improvement of mechanism of bearing capacity and mechanism of spherical expansion by the use of pile-base post grouting technique, as well as the estimation method of the bearing capacity of pile-base pos...
Breaking anchored droplets in a microfluidic Hele-Shaw cell
Amselem, Gabriel; Gallaire, François; Baroud, Charles N
2015-01-01
We study microfluidic self digitization in Hele-Shaw cells using pancake droplets anchored to surface tension traps. We show that above a critical flow rate, large anchored droplets break up to form two daughter droplets, one of which remains in the anchor. Below the critical flow velocity for breakup the shape of the anchored drop is given by an elastica equation that depends on the capillary number of the outer fluid. As the velocity crosses the critical value, the equation stops admitting a solution that satisfies the boundary conditions; the drop breaks up in spite of the neck still having finite width. A similar breaking event also takes place between the holes of an array of anchors, which we use to produce a 2D array of stationary drops in situ.
Simulation analyses of vibration tests on pile-group effects using blast-induced ground motions
International Nuclear Information System (INIS)
Extensive vibration tests have been performed on pile-supported structures at a large-scale mining site to promote better understanding of the dynamic behavior of pile-supported structures, especially pile-group effects. Two test structures were constructed in an excavated pit. One structure was supported on 25 tubular steel piles and the other on 4. The test pit was backfilled with sand of an appropriate grain size distribution to ensure good compaction. Ground motions induced by large-scale blasting operations were used as excitation forces for the tests. The 3D Finite Element Method (3D FEM)and a Genetic Algorithm (GA) were employed to identify the shear wave velocities and damping factors of the compacted sand, especially of the surface layer. A beam-interaction spring model was employed to simulate the test results of the piles and the pile-supported structures. The superstructure and pile foundation were modeled by a one-stick model comprising lumped masses and beam elements. The pile foundations were modeled just as they were, with lumped masses and beam elements to simulate the test results showing that, for the 25-pile structure, piles at different locations showed different responses. It was confirmed that the analysis methods employed were very useful for evaluating the nonlinear behavior of the soil-pile-structure system, even under severe ground motions. (authors)
An Experimental Study on Pile Spacing Effects under Lateral Loading in Sand
Directory of Open Access Journals (Sweden)
Mahdy Khari
2013-01-01
Full Text Available Grouped and single pile behavior differs owing to the impacts of the pile-to-pile interaction. Ultimate lateral resistance and lateral subgrade modulus within a pile group are known as the key parameters in the soil-pile interaction phenomenon. In this study, a series of experimental investigation was carried out on single and group pile subjected to monotonic lateral loadings. Experimental investigations were conducted on twelve model pile groups of configurations 1 × 2, 1 × 3, 2 × 2, 3 × 3, and 3 × 2 for embedded length-to-diameter ratio l/d = 32 into loose and dense sand, spacing from 3 to 6 pile diameter, in parallel and series arrangement. The tests were performed in dry sand from Johor Bahru, Malaysia. To reconstruct the sand samples, the new designed apparatus, Mobile Pluviator, was adopted. The ultimate lateral load is increased 53% in increasing of s/d from 3 to 6 owing to effects of sand relative density. An increasing of the number of piles in-group decreases the group efficiency owing to the increasing of overlapped stress zones and active wedges. A ratio of s/d more than 6d is large enough to eliminate the pile-to-pile interaction and the group effects. It may be more in the loose sand.
Acoustic emission characteristics of subsoil subjected to vertical pile loading in sand
Mao, Wuwei; Aoyama, Shogo; Goto, Shigeru; Towhata, Ikuo
2015-08-01
The response of the subsoil subjected to pile loading is crucial to clarify the bearing mechanism of pile foundations. This study presents a novel acoustic emission (AE) method to monitor the subsoil behavior in a model pile testing system. The AE testing aims to capture the "micro-noises" released from sand grain dislocation and crushing around the pile shaft during penetration. The correlations between the pile settlement and the AE characteristics including count, amplitude and energy are revealed and discussed, highlighting that the ground density and the shear zone formed during pile penetration mainly affect the AE behavior. The results also suggest that the yielding of ground can be determined based on the development of the AE activity. The technique shows promise as an in-situ methodology for monitoring of subsoil behavior during the process of pile loading.
Investigation of Pile- Soil Interaction Subjected to Lateral Loads in Layered Soils
Directory of Open Access Journals (Sweden)
A. Avaei
2008-01-01
Full Text Available To stabilize infrastructures such as tall buildings, bridges, etc., piles are used to resist lateral loads created from earth pressure, wind, waves and earthquake extensively. Pile design requires understanding of how the load is transferred from a pile to surrounding soil and vice versa. Pile properties, soil stress-strain behavior and pile-soil interaction play important roles in pile-response subjected to lateral loads. A study was carried out to investigate the effects of above-mentioned parameters on pile-soil behavior subjected to lateral forces. A comparison was made between the results derived from finite difference and equivalent spring methods by writing a computer program and using a civil engineering package, respectively.
International Nuclear Information System (INIS)
The two air-cooled graphite-moderated production piles at the UK Sellafield site (formerly Windscale) have not operated since the late 1950s following the fire in Pile no. 1 in 1957. Although limited graphite trepanning took place immediately following the fire (mainly in the undamaged reactor, Pile no. 2), it has been deemed necessary to obtain new samples and extensive data to support the intended programme, which is for further 'Safe Storage' of Pile 2 and for the dismantling of Pile no. 1. The reactors (especially Pile no.2) contain significant Wigner energy, and elaborate precautions have been applied to ensure that intrusive operations cannot lead to energy releases. The paper discusses the visual surveys, trepanning procedure and the analytical data which have been obtained from the samples. There appear to be no obstacles to the continued storage of Pile no.2. For Pile no.1, the data will be used to support the safety case now being developed for dismantling and will define acceptable handling, storage and disposal procedures for the graphite blocks. (author)
Statistical fluctuations of the number of neutrons in a pile
International Nuclear Information System (INIS)
The theory of the statistical fluctuations in a pile is extended to the space dependent case, and gives the fluctuations of the number of neutrons in a cell of the core or reflector of the pile. This number changes through elementary processes occurring at random, which are, capture, source, fission and scattering. Of all these processes, fission is the only one which changes more than one neutron at a time and so is responsible of the deviation of the fluctuations from a Poisson law. The importance of this deviation depends on the dimensions of the cell compared to the slowing down length. When the dimensions are small, the fluctuations close to a Poisson law. (author)
Development of in-pile test and evaluation technology
International Nuclear Information System (INIS)
To develop the in-pile test and evaluation technologies using KMRR, basic design of instrumented capsule and auxiliary system for material irradiation test and the related studies are performed. First, reactor and test hole characteristics are summarized, and conceptual design requirements of capsule to KMRR are reviewed. And fundamental principles and criteria for the instrumented capsule design are summarized. Basic design and analysis of instrumented capsule are performed, and design of capsule supporting system are also performed and structural integrity of the system is analyzed. Based on the prior studies, test mock-ups are designed and manufactured, and thermohydraulic and vibration tests are prepared. And, as in-pile test evaluation technologies, KMRR neutron dosimetry and mechanical tests related to material irradiation are investigated. 67 figs, 30 tabs, 41 refs. (Author)
ESTIMATION OF SCOUR HOLE PROPERTIES AROUND VERTICAL PILE USING ANNs
Institute of Scientific and Technical Information of China (English)
A.KHOSRONEJAD; G. A. MONTAZER; M. GHODSIAN
2003-01-01
Correct estimation of the scour around vertical piles in the field exposed to oscillatory waves is very important for many offshore structures and coastal engineering projects. Conventional predictive formulas for the geometric properties of scour hole, however, are not able to provide sufficiently accurate results. Artificial Neural Networks (ANNs) are simplified mathematical representation of the human brain. Three-layer normal feed-forward ANN is a powerful tool for input-output mapping and has been widely used in civil engineering problems. In this article the ANNs approach is used to predict the geometric properties of the scour around vertical pile. Two different ANNs including multilayer perceptron (with four different learning rules) and radial basis functions neural networks are used for this purpose. The results show that a three-layer normal feed-forward multilayer perceptron with quick propagation (QP) learning rule can predict the scour hole properties successfully.
Vibration from underground railways: considering piled foundations and twin tunnels
Kuo, Kirsty Alison
2011-01-01
Accurate predictions of ground-borne vibration levels in the vicinity of an underground railway are greatly sought after in modern urban centers. Yet the complexity involved in simulating the underground environment means that it is necessary to make simplifying assumptions about this system. One such commonly made assumption is to ignore the effects of nearby embedded structures such as piled foundations and neighbouring tunnels. Through the formulation of computationally efficient mathe...
STUDY OF SOFT SOIL REINFORCEMENT USING HYBRID PILE-PVD
Sandyutama, Y.; L.Samang; A. M. Imran; Harianto, T.
2015-01-01
Recently due to the high demand of construction road need the construction in short period. The problem of construction on soft clay is the low bearing capacity and total as well as differential settlements. Therefore, innovation in soil improvement is needed. Soft soil improvement by geotextile and rigid piles is an interesting method to provide and economic and effective solution, which reduces settlements, construction time and cost. Full-scale tests were performed to investigate the perfo...
In-pile experimental facility needs for LMFR safety research
International Nuclear Information System (INIS)
Although the achievement of the safety research during the past years has been significant, there still exists a strong need for future research, especially when there is prospect for future LMFR commercialization. In this paper, our current views are described on future research needs especially with a new in-pile experimental facility. The basic ideas and progress are outlined of a preliminary feasibility study. (author)
Analysis of Sandia in-pile EOS experiments
International Nuclear Information System (INIS)
Preliminary analysis has been carried out of the dynamic in-pile equation-of-state measurements for UO2, conducted at Sandia Laboratories, aimed at reducing the uncertainties in the effective UO2 enthalpy corresponding to the measured pressures. Of the remaining width of the p-H band of some 350 J/g, about 200 J/g originate in the uncertainties of the analytical modelling and about 150 J/g result from the scatter in the experimental data
In-pile loop experiments in water chemistry and corrosion
International Nuclear Information System (INIS)
Methods and techniques used were as follows: (a) Method of polarizing resistance for remote monitoring of instantaneous rate of uniform corrosion. (b) Out-of-pile loop at the temperature 350 degC, pressure 19 MPa, circulation 20 kgs/h, testing time 1000 h. (c) High temperature electromagnetic filter with classical solenoid and ball matrix for high pressure filtration tests. (d) High pressure and high temperature in-pile water loop with coolant flow rate 10 000 kgs/h, neutron flux in active channel 7x1013 n/cm2.s, 16 MPa, 330 degC. (e) Evaluation of experimental results by chemical and radiochemical analysis of coolant, corrosion products and corrosion layer on surface. The results of measurements carried out in loop facilities can be summarized into the following conclusions: (a) In-pile and out-of-pile loops are suitable means of investigating corrosion processes and mass transport in the nuclear power plant primary circuit. (b) In studying transport phenomena in the loop, it is necessary to consider the differences in geometry of the loop and the primary circuit, mainly the ratio of irradiated and non-irradiated surfaces and volumes. (c) In the experimental facility simulating the WWER-type nuclear power plant primary circuit, solid suspended particles of a chemical composition corresponding most frequently to magnetite or nickel ferrite, though with non-stoichiometric composition Mex2+Fe3-x3+O4, were found. (d) Continuous filtration of water by means of an electromagnetic filter removing large particles of corrosion products leads to a decrease in radioactivity of the outer epitactic layer only. The effect of filtration on the inner topotactic layer is negligible
Pile-up reduction by detector-induced beam suppression
International Nuclear Information System (INIS)
The technique of detector-induced beam suppression using a beam deflector and a high power pulse generator has been explored. The γ spectra of the 98Mo(α,xn) reactions are presented with and without beam suppression and it is seen that with the pile-up reduction system working, there is a considerable increase in the count rate in the 98Rn 653 keV peak, with almost the same background. (C.F.)
The Phebus fission products in pile test programme
International Nuclear Information System (INIS)
The need for quantifying the radioactive materials escaping from an LWR Nuclear Power Plant following a melt-down accident has arisen relatively late in the nuclear reactor technology development process. The TMI-2 accident in 1979 and the Chernobyl accident in 1986 have confirmed the importance of a good knowledge of phenomena which take place in a plant undergoing extreme accident conditions. After an extensive resarch effort which has involved the major nuclear countries for several years, we are now at the stage where a selective and converging attitude should be taken towards the wide range of problems underlying severe accidents. Selective, because we must understand what is important and what could be neglected. Converging, because we must arrive at a consensus at international level on the methods to treat these problems and a common understanding of the main scientific phenomena and the models to correctly represent them. After a large amount of separate effects tests and semi-integral in-pile and out-of-pile experiments, the Phebus FP project is being started as an experimental effort to quantify the relative importance of complicated processes and to give an insight into the interconnection of various mechanisms. The overall objective of this programme is to provide a qualified data base of integral in-pile experiments to validate codes dealing with FP transport in reactor core, primary cooling system and containment. This paper describes mainly the motivations and objectives of the Phebus PF programme
NEET In-Pile Ultrasonic Sensor Enablement-Final Report
Energy Technology Data Exchange (ETDEWEB)
J. Daw; J. Rempe; J. Palmer; P. Ramuhalli; R. Montgomery; H.T. Chien; B. Tittmann; B. Reinhardt; P. Keller
2014-09-01
Ultrasonic technologies offer the potential to measure a range of parameters during irradiation of fuels and materials, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes under harsh irradiation test conditions. There are two primary issues that currently limit in-pile deployment of ultrasonic sensors. The first is transducer survivability. The ability of ultrasonic transducer materials to maintain their useful properties during an irradiation must be demonstrated. The second issue is signal processing. Ultrasonic testing is typically performed in a lab or field environment, where the sensor and sample are accessible. The harsh nature of in-pile testing and the variety of desired measurements demand that an enhanced signal processing capability be developed to make in-pile ultrasonic sensors viable. To address these issues, the NEET ASI program funded a three year Ultrasonic Transducer Irradiation and Signal Processing Enhancements project, which is a collaborative effort between the Idaho National Laboratory, the Pacific Northwest National Laboratory, the Argonne National Laboratory, and the Pennsylvania State University. The objective of this report is to document the objectives and accomplishments from this three year project. As summarized within this document, significant work has been accomplished during this three year project.
STABILIZATION OF A FAILED SLOPE WITH PILED STRUCTURES
Directory of Open Access Journals (Sweden)
M. Rifat KAHYAOĞLU
2008-01-01
Full Text Available Neogene aged units of a densely populated region of Western Turkey along the Aegean Sea coastline is susceptible to landslides causing frequent economic loss especially following raining seasons. Several landslides took place in the area covering a narrow band of the coastline between Izmir and Söke (Aydın. Countermeasures against these relatively small-scale slope failures in the region often involve construction of either reinforced concrete retaining walls or stabilizing piles, which can be easily constructed by local contractors. In this study borings, in-situ and laboratory soil mechanics tests, geophysical and geological investigations have been performed in order to investigate the landslide occurred in the yard of an elementary school in Söke township. The analysis of two rows of piled retaining system constructed to reuse the school building against a potential slides are presented. Three inclinometer measurements have been performed after completion of the bored pile system. It has been concluded that the measured and the calculated displacement values are both small. There is no problem of the built project by means of moments and displacements.
Enhanced in-pile instrumentation at the advanced test reactor
International Nuclear Information System (INIS)
Many of the sensors deployed at materials and test reactors cannot withstand the high flux/high temperature test conditions often requested by users at U.S. test reactors, such as the Advanced Test Reactor (ATR) at the Idaho National Laboratory. To address this issue, an instrumentation development effort was initiated as part of the ATR National Scientific User Facility in 2007 to support the development and deployment of enhanced in-pile sensors. This paper reports results from this effort. Specifically, this paper identifies the types of sensors currently available to support in-pile irradiations and those sensors currently available to ATR users. Accomplishments from new sensor technology deployment efforts are highlighted by describing new temperature and thermal conductivity sensors now available to ATR users. Efforts to deploy enhanced in-pile sensors for detecting elongation and realtime flux detectors are also reported, and recently-initiated research to evaluate the viability of advanced technologies to provide enhanced accuracy for measuring key parameters during irradiation testing are noted. (authors)
Enhanced In-Pile Instrumentation at the Advanced Test Reactor
International Nuclear Information System (INIS)
Many of the sensors deployed at materials and test reactors cannot withstand the high flux/high temperature test conditions often requested by users at U.S. test reactors, such as the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL). To address this issue, an instrumentation development effort was initiated as part of the ATR National Scientific User Facility (NSUF) in 2007 to support the development and deployment of enhanced in-pile sensors. This paper reports results from this effort. Specifically, this paper identifies the types of sensors currently available to support in-pile irradiations and those sensors currently available to ATR users. Accomplishments from new sensor technology deployment efforts are highlighted by describing new temperature and thermal conductivity sensors now available to ATR users. Efforts to deploy enhanced in-pile sensors for detecting elongation and real-time flux detectors are also reported, and recently-initiated research to evaluate the viability of advanced technologies to provide enhanced accuracy for measuring key parameters during irradiation testing are noted.
Radiocarbon from Pile Graphite; Chemical Methods for Its Concentrations
Arnold, J. R.; Libby, W. F.
1946-10-10
Samples of pile graphite, irradiated in a test-hole at Hanford for 15 months, have been assayed for radioactive C{sup 14} yielding 0.38 ± 0.04 microcuries per gram. At this level of activity, the pile graphite contains very valuable amounts of C{sup14}. The relation between the above assay and the probable average assay of pile graphite is discussed, and it is concluded that the latter is almost certainly above 0.3 microcuries/gram. Controlled oxidation of this graphite, either with oxygen at ~750ºC, or with chromic acid "cleaning solution" at room temperature, yields early fractions which are highly enriched in C{sup 14}. Concentrations of 5-fold with oxygen, and 50-fold with CrO{sub 3}, have been observed. The relation between the observed enrichment and the Wigner effect is discussed, and a mechanism accounting for the observations put forward. According to this, about 25% of the stable carbon atoms in the lattice have been displaced by Wigner effect, a large fraction of which have healed by migrating to crystal edges. All the C{sup 14} atoms have been displaced, and the same fraction of these migrate to the edges. The enrichment then results from surface oxidation, in the oxygen case. Predictions are made on the basis of this hypothesis. A technique of counting radioactive CO{sub 2} in the gas phase is described.
The infrabuccal pellet piles of fungus-growing ants.
Little, Ainslie E F; Murakami, Takahiro; Mueller, Ulrich G; Currie, Cameron R
2003-12-01
Fungus-growing ants (Attini) live in an obligate mutualism with the fungi they cultivate for food. Because of the obligate nature of this relationship, the success of the ants is directly dependent on their ability to grow healthy fungus gardens. Attine ants have evolved complex disease management strategies to reduce their garden's exposure to potential parasitic microbes, to prevent the establishment of infection in their gardens, and to remove infected garden sections. The infrabuccal pocket, a filtering device located in the oral cavity of all ants, is an integral part of the mechanisms that leaf-cutter ants use to prevent the invasion and spread of general microbial parasites and the specific fungal-garden parasite Escovopsis. Fungus-growing ants carefully groom their garden, collecting general debris and pathogenic spores of Escovopsis in their infrabuccal pocket, the contents of which are later expelled in dump chambers inside the nest or externally. In this study we examined how a phylogenetically diverse collection of attine ants treat their infrabuccal pellets. Unlike leaf-cutters that deposit their infrabuccal pellets directly in refuse piles, ants of the more basal attine lineages stack their infrabuccal pellets in piles located close to their gardens, and a separate caste of workers is devoted to the construction, management, and eventual disposal of these piles. PMID:14676952
Avalanche Structure in the Kadanoff Sand Pile Model
Perrot, Kevin
2011-01-01
Sand pile models are dynamical systems emphasizing the phenomenon of Self Organized Criticality (SOC). From N stacked grains, iterating evolution rules leads to some critical configuration where a small disturbance has deep consequences on the system, involving numerous steps of grain fall. Physicists L. Kadanoff et al. inspire KSPM, a model presenting a sharp SOC behavior, extending the well known Sand Pile Model. In KSPM with parameter D we start from a pile of N stacked grains and apply the rule: D-1 grains can fall from column i onto the D-1 adjacent columns to the right if the difference of height between columns i and i+1 is greater or equal to D. We propose an iterative study of KSPM evolution where one single grain addition is repeated on a heap of sand. The sequence of grain falls following a single grain addition is called an avalanche. From a certain column precisely studied for D=3, we provide a plain process describing avalanches.
In-pile loop experiments in water chemistry and corrosion
International Nuclear Information System (INIS)
Results on the study of Zr-1% Nb alloy corrosion, in out-of and in-pile loops simulating the working conditions of the VVER-440 reactor (Soviet, PWR type), covered the time period May 1982-April 1986 were reported, as well as, results on transport and filtration of corrosion products. Methods and techniques used in the study included remote measurement of corrosion rate by polarizing resistance, out-of-pile loop at the temperature 350 deg. C, pressure 19 MPa, circulation 20 kgs/h and in-pile water loop with constant flow rate 10,000 kgs/h, pressure 16 MPa, temperature 330 deg. C and neutron flux 7x1013 n/cm2.s. It was shown that solid suspended particles with chemical composition corresponding most frequently to magnetite or nickelous ferrite, though with non-stoichiometric composition Mex2+ Fe3-x3+O4 were found. Continuous filtration of water by means of electromagnetic filter leads to a decrease of radioactivity of the outer epitactic layer only. Effect of filtration on the inner topotactic layer is negligible. The corrosion rates for the above-mentioned parameters are given
Vibration tests on pile-group foundations using large-scale blast excitation
International Nuclear Information System (INIS)
Extensive vibration tests have been performed on pile-supported structures at a large-scale mining site. Ground motions induced by large-scale blasting operations were used as excitation forces for vibration tests. The main objective of this research is to investigate the dynamic behavior of pile-supported structures, in particular, pile-group effects. Two test structures were constructed in an excavated 4 m deep pit. One structure had 25 steel tubular piles and the other had 4 piles. The super-structures were exactly the same. The test pit was backfilled with sand of appropriate grain size distributions in order to obtain good compaction, especially between the 25 piles. Accelerations were measured at the structures, in the test pit and in the adjacent free field, and pile strains were measured. The vibration tests were performed six times with different levels of input motions. The maximum horizontal acceleration recorded at the adjacent ground surface varied from 57 cm/s2 to 1683 cm/s2 according to the distances between the test site and the blast areas. Maximum strains were 13,400 micro-strains were recorded at the pile top of the 4-pile structure, which means that these piles were subjected to yielding
Method Cement Post-grouting to Increase the Load Capacity for Bored Pile
Directory of Open Access Journals (Sweden)
Van Loc Nguyen
2013-05-01
Full Text Available Drilled shafts foundations are used as an indispensable solution for long span bridges in Vietnam. In order to increase the bearing capacity, aside from the increasing of the pile length and diameter, an interested way now is treatment of pile bases after concrete placement. This study is aimed at investigating the defect at the bottom of the bored pile from the sonic test. The injection of hight pressure of cement grout to the shaft and tip of the defected bored pile was conducted to increase the bearing capacity of pile. The bearing capacity of defected bored pile is calculated by the TCXD-205:1998 an finite element mothod. After post-grouting technique done, the soil investigation tests have been carried out to define the properties of treated soils. The analytic mothod, finite element method an load test also have been applied to determine the bearing capacity of treated bored pile. The results show that the post-grouting to the shaft and tip of pile can increase two times of bearing capacity of defected bored pile and about 20% compared to the normal bored pile.
Neurostimulation leads, intrathecal catheters and anchoring devices evolution
Directory of Open Access Journals (Sweden)
Laura Demartini
2015-03-01
Full Text Available Many scientific studies highlight the usefulness of spinal cord stimulation and intrathecal therapy for the management of chronic pain syndromes resistant to pharmacological or less invasive interventional therapies. One of the possible complications of these techniques, reported in literature, is migration of the lead or catheter; thus the use of an anchoring system is considered mandatory. Every company that produces devices for neurostimulation or neuromodulation provides various anchoring devices evolved over time. In the study, the authors discuss about the most common anchoring devices based on their clinical experience.
Considerations on the design of through-wall anchors
International Nuclear Information System (INIS)
Connections to existing buildings are often the most difficult planning challenge for the realization of construction measures in case of piping system replacements in nuclear power plants. This is due to restricted space or limited load reserves of the building structure. Usually the realization of support connections to the existing buildings is achieved by anchor bolts. But in critical cases the preferred alternative solution uses through-wall anchors. Up to now uniform assessment thresholds are not available, no technical guidelines or regulations for construction variants exist. Through-wall anchors allow significantly higher load capacities for tensile and shear loads but require enhanced planning and realization efforts.
Trofymow, J. A.; Coops, N.; Hayhurst, D.
2012-12-01
Following forest harvest, residues left on site and roadsides are often disposed of to reduce fire risk and free planting space. In coastal British Columbia burn piles are the main method of disposal, particularly for accumulations from log processing. Quantification of residue wood in piles is required for: smoke emission estimates, C budget calculations, billable waste assessment, harvest efficiency monitoring, and determination of bioenergy potentials. A second-growth Douglas-fir dominated (DF1949) site on eastern Vancouver Island and subject of C flux and budget studies since 1998, was clearcut in winter 2011, residues piled in spring and burned in fall. Prior to harvest, the site was divided into 4 blocks to account for harvest plans and ecosite conditions. Total harvested wood volume was scaled for each block. Residue pile wood volume was determined by a standard Waste and Residue Survey (WRS) using field estimates of pile base area and plot density (wood volume / 0.005 ha plot) on 2 piles per block, by a smoke emissions geometric method with pile volumes estimated as ellipsoidal paraboloids and packing ratios (wood volume / pile volume) for 2 piles per block, as well as by five other GIS methods using pile volumes and areas from LiDAR and orthophotography flown August 2011, a LiDAR derived digital elevation model (DEM) from 2008, and total scaled wood volumes of 8 sample piles disassembled November 2011. A weak but significant negative relationship was found between pile packing ratio and pile volume. Block level avoidable+unavoidable residue pile wood volumes from the WRS method (20.0 m3 ha-1 SE 2.8) were 30%-50% of the geometric (69.0 m3 ha-1 SE 18.0) or five GIS/LiDAR (48.0 to 65.7 m3 ha-1 ) methods. Block volumes using the 2008 LiDAR DEM (unshifted 48.0 m3 ha-1 SE 3.9, shifted 53.6 m3 ha-1 SE 4.2) to account for pre-existing humps or hollows beneath piles were not different from those using the 2011 LiDAR DEM (50.3 m3 ha-1 SE 4.0). The block volume ratio
Maxillary sinus perforation by orthodontic anchor screws.
Motoyoshi, Mitsuru; Sanuki-Suzuki, Rina; Uchida, Yasuki; Saiki, Akari; Shimizu, Noriyoshi
2015-06-01
To facilitate safe placement of orthodontic anchor screws (miniscrews), we investigated the frequency of maxillary sinus perforation after screw placement and the effect of sinus perforation on screw stability. Maxillary sinus perforations involving 82 miniscrews (diameter, 1.6 mm; length, 8 mm) were evaluated using cone-beam computed tomography. All miniscrews were placed in maxillary alveolar bone between the second premolar and first molar for anchorage for anterior retraction in patients undergoing first premolar extraction. The placement torque and screw mobility of each implant were determined using a torque tester and a Periotest device, and variability in these values in relation to sinus perforation was evaluated. Eight of the 82 miniscrews perforated the maxillary sinus. There was no case of sinusitis in patients with miniscrew perforation and no significant difference in screw mobility or placement torque between perforating and non-perforating miniscrews. The sinus floor was significantly thinner in perforated cases than in non-perforated cases. A sinus floor thickness of 6.0 mm or more is recommended in order to avoid miniscrew perforation of the maxillary sinus. PMID:26062857
Anchored boundary conditions for locally isostatic networks
Theran, Louis; Nixon, Anthony; Ross, Elissa; Sadjadi, Mahdi; Servatius, Brigitte; Thorpe, M. F.
2015-11-01
Finite pieces of locally isostatic networks have a large number of floppy modes because of missing constraints at the surface. Here we show that by imposing suitable boundary conditions at the surface the network can be rendered effectively isostatic. We refer to these as anchored boundary conditions. An important example is formed by a two-dimensional network of corner sharing triangles, which is the focus of this paper. Another way of rendering such networks isostatic is by adding an external wire along which all unpinned vertices can slide (sliding boundary conditions). This approach also allows for the incorporation of boundaries associated with internal holes and complex sample geometries, which are illustrated with examples. The recent synthesis of bilayers of vitreous silica has provided impetus for this work. Experimental results from the imaging of finite pieces at the atomic level need such boundary conditions, if the observed structure is to be computer refined so that the interior atoms have the perception of being in an infinite isostatic environment.
Stone anchors from the Okhamandal region, Gujarat Coast, India
Digital Repository Service at National Institute of Oceanography (India)
Sundaresh; Gaur, A.S.; Gudigar, P.; Tripati, S.; Vora, K.H.; Bandodkar, S.N.
Dwarka and Armada yielded a number of stone anchors which suggest that Okhamandal area was major concentration of maritime activities in Saurashtra region in the past. Among these three sites, Bet Dwarka has clear evidence on the settlement of Harappan...
Dynamic stiffness of pile groups in a multilayered soil. Part 2
International Nuclear Information System (INIS)
A rational analysis method is presented for calculation of the dynamic stiffness of pile groups in multilayered soil. In this paper, thin layered method is applied, and the dynamic stiffness matrix is evaluated at the pile heads. The pile is modelled as compressible Timoshenko-beam elements and the soil as visco-elastic thin layered elements. After the correlation studies between the analysis and the test results of the pile foundation with a gap between the foundation bottom and the ground surface, the analysis method is amended for the dynamic stiffness of the pile foundation without a gap or with embedment. For these correlation analyses, the presented methods are verified to be applicable for the evaluation of pile group foundation stiffness
Field study of plastic tube cast-in-place concrete pile
Institute of Scientific and Technical Information of China (English)
陈永辉; 曹德洪; 王新泉; 杜海伟; 张霆
2008-01-01
The compositions, technical principles and construction equipments of a new piling method used for ground improvement plastic tube cast-in-place concrete pile were introduced. The results from static load tests on single piles with different forms of pile shoes and on their composite foundations were analyzed. The distribution patterns of axial force, shaft friction and toe resistance were studied based on the measurements taken from buried strain gauges. From the point of engineering application, the pile has merits in convenient quality control, high bearing capacity and reliable quality, showing higher reasonability, advancement and suitability than other ground improvement methods. The pile can be adopted properly to take place of ordinary ground improvement method, achieving greater economical and social benefits.
EURIPIDES, load tests on large driven piles in dense silica sands
Energy Technology Data Exchange (ETDEWEB)
Zuidberg, H.M.; Vergobbi, P.
1996-12-31
In 1995 an extensive load testing program was conducted on 30 inch pipe piles in dense silica sands similar to those found in the southern North Sea. A highly instrumented pile was driven at one location, extracted and redriven at a second location. A total of twelve static compression and tension load tests were performed at three penetration depths between 30 and 47 meters. Test objectives included acquiring reliable data on capacity of offshore type piles in sands which hitherto were hardly available and to understand the failure mechanisms in order to improve current foundation design. The paper describes the design of the testing program and project organization and funding. Details of the test pile and instrumentation to measure the loads in the pile and the pile-sand interaction are highlighted with an emphasis on quality of the measurements. The field-work and innovative testing facilities are also described.
3D FEM Numerical Simulation of Seismic Pile-supported Bridge Structure Reaction in Liquefying Ground
Directory of Open Access Journals (Sweden)
Ling XianZhang, Tang Liang and Xu Pengju
2011-04-01
Full Text Available This study examines the establishment of liquefied ground pile-soil-bridge seismic interaction analysis of three-dimensional finite element analysis method for the simulation of liquefied ground shaking table test of pile-soil seismic interaction analysis, undertake OpenSees finite element based numerical simulation platform, for the shaking table test based on two-phase saturated porous media, Comparative numerical and experimental results, detailed test pile dynamic response of bridge structure and dynamic properties, especially liquefaction pore pressure, liquefaction of pile foundation and the dynamic response of the free field. Finite element method can reasonably predict the site of pore pressure, dynamic response; despite the conventional beam element simulation of pile, pile dynamic response can still accurately simulated.
The Shielding Effect of Multi-Pile Structures on Ice Force
Institute of Scientific and Technical Information of China (English)
史庆增; 黄焱; 宋安
2004-01-01
The shielding effect of the front pile-row on the ice force acting on the back pile-row is studied by ice force model tests. In the tests, the front pile-row is designed to model jacket legs and the back pile-row to model the water resisting pipe-phalanx within the jacket. The shielding factor for ice force corresponding to different conditions are given in this paper. The research indicates that there are many factors, including the longitudinal and lateral spacing between the front and back pile-row, ice attacking angle and the ratio of pile diameter to ice thickness, that influence the shielding effect on ice force.
Experimental Comparison of Statically and Cyclically Loaded Non-Slender Piles in Sand
DEFF Research Database (Denmark)
Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo
rigid form of motion. The Winkler model approach, employing p-y curves to describe the soil-pile interaction, is often employed as the design method for laterally loaded piles. The p-y curve formulation, currently recommended by the American Petroleum Institute and Det Norske Veritas, is based on tests...... applied and hence the effective stresses in the soil have been increased homogeneously. The tests have been conducted in a pressure tank at Aalborg University. A total of 29 quasi-static tests and 14 cyclic tests have been conducted on laterally loaded piles situated in sand. Aluminium pipe piles......The monopile foundation concept is often employed as foundation for offshore wind energy converters. Typically, monopiles are hollow piles made of steel with outer diameters, D, in the range of four to six meters and length to diameter ratios, L/D, around five. Hence, the piles exhibit a rather...
Liquid crystal director fluctuations and surface anchoring by molecular simulation
Andrienko, D.; Germano, G; Allen, M. P.
2002-01-01
We propose a simple and reliable method to measure the liquid crystal surface anchoring strength by molecular simulation. The method is based on the measurement of the long-range fluctuation modes of the director in confined geometry. As an example, molecular simulations of a liquid crystal in slab geometry between parallel walls with homeotropic anchoring have been carried out using the Monte Carlo technique. By studying different slab thicknesses, we are able to calculate separately the pos...
Neurostimulation leads, intrathecal catheters and anchoring devices evolution
Laura Demartini; Gianluca Conversa; Luciana Armiento; Lucia Angelini; Cesare Bonezzi
2015-01-01
Many scientific studies highlight the usefulness of spinal cord stimulation and intrathecal therapy for the management of chronic pain syndromes resistant to pharmacological or less invasive interventional therapies. One of the possible complications of these techniques, reported in literature, is migration of the lead or catheter; thus the use of an anchoring system is considered mandatory. Every company that produces devices for neurostimulation or neuromodulation provides various anchoring...
Monetary sterilization and dual nominal anchors: some Caribbean examples
Khemraj, Tarron; Pasha, Sukrishnalall
2011-01-01
This paper notes that a high sterilization coefficient plus a de facto pegged exchange rate indicates the existence of dual nominal anchors. The econometric evidence presented shows that several Caribbean economies with fixed exchange rate regimes also possess high sterilization coefficients. Given open capital accounts in the various economies, the paper argues that this finding contravenes the money neutrality thesis, which holds that only one nominal anchor can prevail in the long-term. Th...
Epidermolysis Bullosa Acquisita: Autoimmunity to Anchoring Fibril Collagen
Chen, Mei; Kim, Gene H; Prakash, Lori; Woodley, David T.
2011-01-01
Epidermolysis bullosa acquisita (EBA) is a rare and acquired autoimmune subepidermal bullous disease of the skin and mucosa. EBA includes various distinct clinical manifestations resembling Bullous Pemphigus, Brunsting-Perry pemphigoid, or cicatricial pemphigoid. These patients have autoantibodies against type VII collagen, an integral component of anchoring fibrils, which are responsible for attaching the dermis to the epidermis. Destruction or perturbation of the normally functioning anchor...
Transosseous Acetabular Labral Repair as an Alternative to Anchors
Pérez-Carro, Luis; Cabello, Andres Gonzalez; Rakha, Mohamed Ibrahim; Patnaik, Sarthak; Centeno, Elias; Miranda, Victor; Fernández, Ana Alfonso
2015-01-01
Labral tears are the most common pathology in patients undergoing hip arthroscopy and the most common cause of mechanical hip symptoms. Labral repair techniques have been described in the literature using suture anchors placed as close as possible to the acetabular rim without penetrating the articular surface. Optimal surgical technique for labral repair is very important, and an inappropriate entry point and guide angulation may lead to intra-articular penetration of the anchor, chondral da...
The Effect of Anchoring Sutures on Medicinal Leech Mortality
Davila, Victor J.; Hoppe, Ian C.; Landi, Rocco; Ciminello, Frank S.
2009-01-01
Objective: The implementation of leech therapy for surgical flaps is not always logistically easy or comfortable for patients or healthcare providers. We examine different methods of placing sutures in the medicinal leech, Hirudo medicinalis, to make the implementation of leech therapy easier. Methods: Sixteen leeches were randomly divided into 3 groups: a control group, a deep anchoring suture group, and a superficial anchoring suture group. The leeches were observed to determine if either o...
Seismic bridge pier analysis for pile foundation by force and displacement based approaches
Singh NP.R.; Vinayak Hemant Kumar
2015-01-01
Seismic analysis of bridge pier supported on pile foundation requires consideration of soil-pile-structure (kinematic and inertial) interactions. This paper presents the design forces generated for bridge piers with varying height and constant diameter for medium and soft soils in earthquake probability zones considering contribution of soil-pile-structure interactions by developed analytical approaches. The results have shown that the difference in base sh...
Dynamic Instability of Pile-Supported Structures in Liquefiable Soils during Earthquakes
Adhikari, S.; Bhattacharya, S.
2008-01-01
Piles are long slender columns installed deep into the ground to support heavy structures such as oil platforms, bridges, and tall buildings where the ground is not strong enough to support the structure on its own. In seismic prone zones, in the areas of soft soils (loose to medium dense soil which liquefies like a quick sand) piles are routinely used to support structures (buildings/ bridges). The pile and the building vibrate, and often collapse, in liquefiable soils during major earthquak...
Biocchi, Nicola
2011-01-01
Four instrumented sites, with a total of 14 instrumented piles, have been analysed to understand the structural behaviour of the piles and the geotechnical behaviour of the stabilised slopes. Vibrating wire strain gauges are used for the calculation of the bending moment applied to the piles, while inclinometers are used to measure the displacements. A review of the instrumentation has been carried out and a methodology for processin and analysing strain gauges data has been developed. Concre...
Simplified Boundary Element Method for Kinematic Response of Single Piles in Two-Layer Soil
Fayun Liang; Haibing Chen; Wei Dong Guo
2013-01-01
A simple approach is formulated to predict the elastic, kinematic pile bending during harmonic or transient excitation for a circular pile (rather than a simplified thin strip). The kinematic response of a pile embedded in two-layer soil is resolved in the frequency domain caused by the upward propagation of shear waves from the underlying bedrock. The simplified approach is generally valid to nonhomogeneous soil profiles, in light of the good comparison with the dynamic FE method and BDWF so...
Influence of axial load on the lateral pile groups response in cohesionless and cohesive soil
Institute of Scientific and Technical Information of China (English)
Jasim M. ABBASA[1; Zamri CHIK[2; Mohd Raihan TAHA[2
2015-01-01
The lateral response of single and group of piles under simultaneous vertical and lateral loads has been analyzed using a 3D finite element approach. The response in this assessment considered lateral pile displacement and lateral soil resistance and corresponding p-y curve. As a result, modified p-y curves for lateral single pile response were improved with respect to the influence of increasing axial load intensities. The improved plots can be used for lateral loaded pile design and to produce the group action design p-multiplier curves and equations. The effect of load combination on the lateral pile group response was performed on three pile group configurations （i.e., 2 × 1, 2 × 2 and 3 × 2） with four pile spacings （i.e., s = 2D, 4D, 6D and 8D）. As a result, design curves were developed and applied on the actual case studies and similar expected cases for assessment of pile group behavior using improved p-multiplier. A design equation was derived from predicted design curves to be used in the evaluation of the lateral pile group action taking into account the effect of axial load intensities. It was found that the group interaction effect led to reduced lateral resistance for the pile in the group relative to that for the single pile in case of pure lateral load. While, in case of simultaneous combined loads, large axial load intensities （i.e., more than 6H, where H is lateral load values） will have an increase inp-multiplier by approximately 100% and will consequently contribute to greater group piles capacities.
Decommissioning and dismantling of 305-M test pile at the Savannah River Plant
International Nuclear Information System (INIS)
The 305-M Test Pile was started up at the Savannah River Plant in 1952 and operated until 1981. The pile was used to measure the uranium content of reactor fuel. In 1984 work began to decommission and dismantle the pile. Extensive procedures were used that included a detailed description of the radiological controls and safety measures. These controls allowed the job to be completed with radiation doses as low as reasonably achievable
Settlement Analysis of Saturated Tailings Dam Treated by CFG Pile Composite Foundation
Jinxing Lai; Houquan Liu; Junling Qiu; Jianxun Chen
2016-01-01
Cement fly ash gravel (CFG) pile composite foundation is an effective and economic foundation treatment approach, which is significant to building foundation, subgrade construction, and so forth. The present paper aims at investigating the settlement behaviors of saturated tailings dam soft ground under CFG pile composite foundation treatment, in which FEM and laboratory model test were utilized. The proposed findings demonstrate that CFG pile treatment is effective in reinforcing saturated t...
A data-driven approach to pile-up at high luminosity
Hautmann, F
2015-01-01
We discuss recent results on pile-up based on a data-driven jet-mixing method. We illustrate prospects for experimental searches and precision studies in high pile-up regimes at high-luminosity hadron colliders, showing how the jet mixing approach can be used, also outside tracker acceptances, to treat correlation observables and effects of hard jets from pile-up.
Anchor stud monotonic and cyclic shear tests. Final report
International Nuclear Information System (INIS)
In a prestressed concrete reactor vessel (PCRV), the main cavity liner and other cavity liners with large diameter/thickness (D/t) ratios are anchored to the concrete by anchor studs. These anchor studs are subject to shear loading resulting from prestressing, pressurization, temperature, and creep of the PCRV. The test program discussed in this report consists of both monotonic and cyclic testing of models simulating the prototype anchor stud/concrete assembly. The tests determined the shear stiffness characteristics of the 3/4-in.-diameter, one-piece Nelson anchor stud embedded in concrete and established its low-cycle fatigue life under displacement-controlled loading. The previously obtained results of Phase I and Phase II tests on two-piece anchor studs, along with high-cyclic fatigue data taken from the literature, are discussed and are plotted with the current, Phase III, results to form a displacement versus cycles to failure curve covering a useful range of design applications
Evaluation of mitral valve replacement anchoring in a phantom
McLeod, A. Jonathan; Moore, John; Lang, Pencilla; Bainbridge, Dan; Campbell, Gordon; Jones, Doug L.; Guiraudon, Gerard M.; Peters, Terry M.
2012-02-01
Conventional mitral valve replacement requires a median sternotomy and cardio-pulmonary bypass with aortic crossclamping and is associated with significant mortality and morbidity which could be reduced by performing the procedure off-pump. Replacing the mitral valve in the closed, off-pump, beating heart requires extensive development and validation of surgical and imaging techniques. Image guidance systems and surgical access for off-pump mitral valve replacement have been previously developed, allowing the prosthetic valve to be safely introduced into the left atrium and inserted into the mitral annulus. The major remaining challenge is to design a method of securely anchoring the prosthetic valve inside the beating heart. The development of anchoring techniques has been hampered by the expense and difficulty in conducting large animal studies. In this paper, we demonstrate how prosthetic valve anchoring may be evaluated in a dynamic phantom. The phantom provides a consistent testing environment where pressure measurements and Doppler ultrasound can be used to monitor and assess the valve anchoring procedures, detecting pararvalvular leak when valve anchoring is inadequate. Minimally invasive anchoring techniques may be directly compared to the current gold standard of valves sutured under direct vision, providing a useful tool for the validation of new surgical instruments.
Anchor Plates in Two-Layered Cohesion Less Soils
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Hamed Niroumand
2010-01-01
Full Text Available Problem statement: During the past few years a great number of experimental model and numerical analysis results on the uplift resistance of anchor plate embedded in homogeneous cohesion less soil has been reported by many researchers. A review of related literature shows that not much research has been done to analyze the performance of anchor plates in layered soils a problem, which is often encountered by the professional engineers in the field. Approach: This study presented the performance of the anchor plates in the cohesion less soil by different researchers. It was based on different previous researches, from the earliest till the most recent ones. The main aim of this research was focused on the prediction of the anchor plates behavior and the force in the layered cohesion less soils. Few laboratory studies were conducted to investigate the uplift capacity behavior of cohesion less soil by previous researchers. Results: The experimental and numerical investigation included uplift test on cohesion less soil by last researchers. The embedment ratio and the effect of density on uplift response were evaluated. This analysis was investigated experimentally and numerically behavior of anchor plates buried in two layered cohesion less soil. Although earlier researchers developed experimentally expressions to estimate the uplift capacity of irregular anchor plates in layered cohesion less soils. Conclusion: The study observed that the ultimate uplift capacity is dependent on the relative strength of the two layers, the depth ratio of embedment and the upper layer thickness ratio.
Pyramidal anchor stone from Baga waters of Goa, west coast of India
Digital Repository Service at National Institute of Oceanography (India)
Tripati, S.
. Pyramidal anchor stones have an apex hole which goes up to the round hole, however Goa anchor stone has no such perforation, but, instead has a rectangular cutting on the apex. The anchor stone is compared with Greek pyramidal anchor stones, and probably...
Tang, Liang; Maula, Baydaa Hussain; Ling, Xianzhang; Su, Lei
2014-03-01
A shake-table experiment on pile foundations in liquefiable soils composed of liquefiable sand and overlying soft clay is studied. A three-dimensional (3D) effective stress finite element (FE) analysis is employed to simulate the experiment. A recently developed multi-surface elasto-plastic constitutive model and a fully coupled dynamic inelastic FE formulation ( u- p) are used to model the liquefaction behavior of the sand. The soil domains are discretized using a solid-fl uid fully coupled ( u- p) 20-8 noded brick element. The pile is simulated using beam-column elements. Upon careful calibration, very good agreement is obtained between the computed and the measured dynamic behavior of the ground and the pile. A parametric analysis is also conducted on the model to investigate the effect of pile-pinning, pile diameter, pile stiffness, ground inclination angle, superstructure mass and pile head restraints on the ground improvement. It is found that the pile foundation has a noticeable pinning effect that reduces the lateral soil displacement. It is observed that a larger pile diameter and fixed pile head restraints contribute to decreasing the lateral pile deformation; however, a higher ground inclination angle tends to increase the lateral pile head displacements and pile stiffness, and superstructure mass seems to effectively influence the lateral pile displacements.
Studying and Preparing of Basic Time for Piling Works by Synthetic Equations
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Naiyakeat Pongpatanasuegsa
2011-10-01
Full Text Available The objective of this research is to study and prepare basic time for piling works by synthetic equations. The time data of 7 work elements of piling works were collected from 10 different construction sites in Phuket Province of Thailand. The synthetic equations were derived with multiple regressions analysis method using statistic software package. These work elements consisted of pile driving work , moving piling rig left or right on supporting rails , moving supporting rails left or right , moving piling rig and supporting rails back or forth, joining of two-piece pile by welding, joining of two-piece pile by steel coupling , and pile driving with pushing post. These synthetic equations were used to determine the basic time, standard time, and productivity values for various types and sizes of square precast concrete pile. The researchers found that these productivity values were reliable compared to general practice, and could be applied in construction planning and scheduling in Phuket province or other area with similar geological conditions.
Theoretical study on setup of expanded-base pile considering cavity contraction
Institute of Scientific and Technical Information of China (English)
齐昌广; 刘干斌; 王艳; 邓岳保
2015-01-01
When an expanded-base pile is installed into ground, the cavity expansion associated with penetration of the enlarged pile base is followed by cavity contraction along the smaller-diameter pile shaft. In order to account for the influence of cavity contraction on the change of bearing capacity of expanded-base pile, a theoretical calculation methodology, predicting the setup of expanded-base pile, was established by employing the cavity contraction theory to estimate the shaft resistance of expanded-base pile, and horizontal consolidation theory to predict the dissipation of excess pore pressure. Finally, the numerical solutions for the setup of expanded-base pile were obtained. The parametric study about the influence of cavity contraction on setup of expanded-base pile was carried out, while a field test was introduced. The parametric study shows that the decrements in radial pressure and the maximum pore water pressure after considering cavity contraction are increased as the expanded ratio (base diameter/shaft diameter) and rigidity index of soil are raised. The comparison between calculated and measured values shows that the calculated results of ultimate bearing capacity for expanded-base pile considering cavity contraction agree well with the measured values; however, the computations ignoring cavity contraction are 2.5−3.0 times the measured values.
Theoretical study on setup of expanded-base pile considering cavity contraction
Institute of Scientific and Technical Information of China (English)
齐昌广; 刘干斌; 王艳; 邓岳保
2015-01-01
When an expanded-base pile is installed into ground, the cavity expansion associated with penetration of the enlarged pile base is followed by cavity contraction along the smaller-diameter pile shaft. In order to account for the influence of cavity contraction on the change of bearing capacity of expanded-base pile, a theoretical calculation methodology, predicting the setup of expanded-base pile, was established by employing the cavity contraction theory to estimate the shaft resistance of expanded-base pile, and horizontal consolidation theory to predict the dissipation of excess pore pressure. Finally, the numerical solutions for the setup of expanded-base pile were obtained. The parametric study about the influence of cavity contraction on setup of expanded-base pile was carried out, while a field test was introduced. The parametric study shows that the decrements in radial pressure and the maximum pore water pressure after considering cavity contraction are increased as the expanded ratio(base diameter/shaft diameter) and rigidity index of soil are raised. The comparison between calculated and measured values shows that the calculated results of ultimate bearing capacity for expanded-base pile considering cavity contraction agree well with the measured values; however, the computations ignoring cavity contraction are 2.5-3.0 times the measured values.
Comparative Model Tests of SDP and CFA Pile Groups in Non-Cohesive Soil
Krasiński, Adam; Kusio, Tomasz
2015-02-01
The research topic relates to the subject of deep foundations supported on continuous flight auger (CFA) piles and screw displacement piles (SDP). The authors have decided to conduct model tests of foundations supported on the group of piles mentioned above and also the tests of the same piles working as a single. The tests are ongoing in Geotechnical Laboratory of Gdaňsk University of Technology. The description of test procedure, interpretation and analysis of the preliminary testing series results are presented in the paper.
Estimate of the residual loads obtained in the end of piles driven in porous soils
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David de Carvalho
2005-02-01
Full Text Available In the geotechnical engineering the study about the quantification of the residual loads in the pile end, after the end of the first loading of the load test attempt, highlighted some works on its interpretation in the curve load versus pile settlement. The construction of a mathematical model to study such a phenomenon is based on the Relations of Cambefort Precast-concrete piles were specially built for this research. They have special elements installed all along their length where the residual loads inlaid in the pile end region could be measured by means of deformation strain gauges.
In-pile IASCC growth tests of irradiated stainless steels in JMTR
International Nuclear Information System (INIS)
The Japan Atomic Energy Agency (JAEA) has an in-pile irradiation-assisted stress corrosion cracking (IASCC) test plan to evaluate in-situ effects of neutron/γ-ray irradiation on crack growth of irradiated stainless steels under high-temperature water conditions for commercial boiling water reactors (BWRs) using the Japan Materials Testing Reactor (JMTR). Crack growth rate and its electrochemical corrosion potential (ECP) dependence are different between in-pile test and post irradiation examination (PIE), but these differences are not fully understood. The objectives of the present study are to understand the difference between in-pile and out-of-pile IASCC growth and to confirm the effectiveness of mitigation due to lowering ECP on in-pile crack growth rates. For in-pile crack growth tests, we have selected a large compact tension specimen such as 0.5T-CT because of validity of SCC growth test at a high stress intensity factor (K-value). For loading a 0.5T-CT specimen up to K - 30 MPa √m, we have adopted a lever type loading unit for in-pile crack growth tests in the JMTR. In this report, an in-pile test plan for crack growth of irradiated SUS316L stainless steels under simulated BWR conditions in the JMTR and current status of development of in-pile crack growth test techniques are presented. (author)
Method Cement Post-grouting to Increase the Load Capacity for Bored Pile
Loc Nguyen; Lei Nie; Min Zhang
2013-01-01
Drilled shafts foundations are used as an indispensable solution for long span bridges in Vietnam. In order to increase the bearing capacity, aside from the increasing of the pile length and diameter, an interested way now is treatment of pile bases after concrete placement. This study is aimed at investigating the defect at the bottom of the bored pile from the sonic test. The injection of hight pressure of cement grout to the shaft and tip of the defected bored pile was conducted to increas...
Chemical transport beneath a uranium mill tailings pile, Riverton, Wyoming
International Nuclear Information System (INIS)
A detailed geochemical study at the Riverton site was undertaken in order to define the nature of chemical transport between an inactive tailings pile and the relationship between the underlying shallow groundwater system. Isotopic measurements of oxygen, deuterium, and tritium showed that although both the shallow alluvial aquifer and a deeper aquifer in the Wind River Formation were derived from a similar source, the nearby river, recharge from the tailings pile is occurring only in the shallow alluvium. 34S/32S ratios are used as a conservative tracer in defining zones of tailings water contamination. Offsite, drilling has revealed the existence of a chemical plume in which calcium and sulfate concentrations are an order of magnitude or more above background. The plume is also characterized by high dissolved molybdenum concentrations. Pore waters in the tailings exhibit extremely high concentrations of Al, Fe and SO4 and low pH. The dissolution of calcite occurs in the alluvium beneath the pile which is characterized by high partial pressures of CO/sub 2(g)/ in the tailings while serving to neutralize pH. The groundwater, however remains saturated with CaCO3, suggesting that a buffering capacity is active. Beneath and downgradient from the tailings, the groundwater becomes saturated with gypsum. The chemical speciation code, PHREEQE, was used to model mixing reactions, assuming a hydrologically static system. Reaction path simulations were fit to observed trends of pH that were depressed in the contaminated groundwater. The simulations estimate one percent mixing of tailings-pore water with groundwater from the shallow alluvial aquifer
In-pile behaviour analyses of the monitoring fuel rods
International Nuclear Information System (INIS)
As test objects for the Proving Test on the Reliability of BWR 8x8 Fuel Assemblies, 10 monitoring fuel assemblies were irradiated under normal conditions in a typical commercial BWR. Seven were subjected to detailed post-irradiation examination and a large amount of data was obtained on in-pile fuel rod behaviour. On the basis of these data, fuel rod behaviour is discussed. A new computer code for thermal-mechanical analysis of the fuel rods was used to analyse the behaviour of the punctured rods, which had exposures ranging from 4 to 32 GW·d/t. These monitoring fuel rods showed a very small decrease due to cladding creep-down. Pellet-cladding mechanical interaction (PCMI) was first considered to have caused this increase, but no evidence was found of a PCMI large enough to have resulted in permanent strain on the cladding. From the data on diameter change, most of the increase was then attributed to cladding surface corrosion and crud deposition. The fission gas release (FGR) rate showed a distinctive exposure dependency. At exposures lower than 10 GW·d/t all FGR data were less than 1%; however, above 10 GW·d/t they showed large scatter, from 0.1 to 20%. Data from microgamma scanning indicated the existence of a threshold temperature for FGR. This temperature depended on exposure and the local FGR rate increased rapidly with a temperature above the threshold. This rapid increase of the local FGR rate may be the reason for the distinctive data scattering. Pellet density changes were also compared with out-of-pile test results. Through evaluation work, a better understanding of the in-pile behaviour of commercial fuel rods has been achieved and the reliability of the BWR fuel rods has been verified; the prediction capability of the new code was also confirmed. (author)
Pile-Up Discrimination Algorithms for the HOLMES Experiment
Ferri, E.; Alpert, B.; Bennett, D.; Faverzani, M.; Fowler, J.; Giachero, A.; Hays-Wehle, J.; Maino, M.; Nucciotti, A.; Puiu, A.; Ullom, J.
2016-07-01
The HOLMES experiment is a new large-scale experiment for the electron neutrino mass determination by means of the electron capture decay of ^{163}Ho. In such an experiment, random coincidence events are one of the main sources of background which impair the ability to identify the effect of a non-vanishing neutrino mass. In order to resolve these spurious events, detectors characterized by a fast response are needed as well as pile-up recognition algorithms. For that reason, we have developed a code for testing the discrimination efficiency of various algorithms in recognizing pile up events in dependence of the time separation between two pulses. The tests are performed on simulated realistic TES signals and noise. Indeed, the pulse profile is obtained by solving the two coupled differential equations which describe the response of the TES according to the Irwin-Hilton model. To these pulses, a noise waveform which takes into account all the noise sources regularly present in a real TES is added. The amplitude of the generated pulses is distributed as the ^{163}Ho calorimetric spectrum. Furthermore, the rise time of these pulses has been chosen taking into account the constraints given by both the bandwidth of the microwave multiplexing read out with a flux ramp demodulation and the bandwidth of the ADC boards currently available for ROACH2. Among the different rejection techniques evaluated, the Wiener Filter technique, a digital filter to gain time resolution, has shown an excellent pile-up rejection efficiency. The obtained time resolution closely matches the baseline specifications of the HOLMES experiment. We report here a description of our simulation code and a comparison of the different rejection techniques.
Welding Techniques for In-Pile Instrumentation at INR Pitesti
International Nuclear Information System (INIS)
Welding is widely involved in developing in-pile instrumentation, regarding both attaching sensors and joining components of the in-pile experimental devices. Although new methods were not developed, we combined existing techniques, aiming to master them and to ensure reproducibility, sensitivity, robustness, and fast response (for sensor welding). In this paper we present results regarding thermocouple welded on cladding, and dissimilar joints. Techniques for welding K-type thermocouples on cladding were designated to ensure robust joints able to resist during pressure and temperature transients, to minimize the perturbation on temperature field and on the cladding material structure, to reproduce the joint shape and dimension, and to ensure fast response. Welded or brazed joints between materials with properties suitable to nuclear applications are often required for in-pile instrumentation to allow coupling to other components of the experimental devices. The paper describes work related to Zircaloy-to-Stainless Steel joint through eutectic vacuum brazing. The eutectic was produced by thermal diffusion of the elements in the base materials at their interface, through formation of liquid phases of Zr-Fe and Zr-Ni systems at the Zy-SS interface. Clean, reduced roughness, oxide-free contact interface, and precise temperature control were aimed. The optimal interface was the joint on perfectly matching truncated cone surfaces. Heating to 1030oC was obtained through vacuum induction at 10 kHz frequency, with vacuum between 10-5 and 10-6 mbar. Other dissimilar joints were micro-TIG welds on SS capillary connected to Inconel-Incoloy capsules, for high pressure measurement lines with small internal volume. To evaluate the joints burst tests (for thermocouple welding only) polarized light metallography, macrography, backscattered electron tests, Helium leak test, tensile test, and thermal cycling tests were performed. (author)
Directory of Open Access Journals (Sweden)
R. Ananda Kumar
2015-01-01
Full Text Available Abstract Retrofitting works are immensely essential for deteriorated and damaged structures in Engineering and Medical fields in order to keep or return to the originality for safe guarding the structures and consumers. In this paper different types of methods of retrofitting review notes are given based on the experimental numerical and analytical methods results on strengthening the Reinforced cement concrete RCC structures including RCC piles. Soil-pile interaction on axial load lateral load reviews are also presented. This review paper is prepared to find out the performance of basalt fibre reinforced polymer BFRP composite retrofitted reinforced cement concrete single end bearing piles.
Estudio acústico del Conservatorio de Piles
VILLA MORANT, SARA
2014-01-01
El objetivo de este proyecto es realizar un estudio acústico general de la "Casa de la Cultura" de Piles, sobre todo de los recintos que más lo requieren, como la sala principal de música. El edificio, al tratarse de una construcción antigua, no reúne las especificaciones acústicas establecidas en el Código Técnico vigente en la actualidad. En primer lugar, se realiza el estudio del acondicionamiento acústico de la sala principal, entendiéndose como acondicionamiento acústico la definición de...
E-pile model of self-organized criticality
Milovanov, Alexander V.; Rasmussen, Jens Juul; Rypdal, Kristoffer
2007-01-01
The concept of percolation is combined with a self-consistent treatment of the interaction between the dynamics on a lattice and the external drive. Such a treatment can provide a mechanism by which the system evolves to criticality without fine tuning, thus offering a route to self-organized criticality (SOC) which in many cases is more natural than the weak random drive combined with boundary loss/dissipation as used in standard sand-pile formulations. We introduce a new metaphor, the e-pil...
Perceptual anchoring in preschool children: not adultlike, but there.
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Karen Banai
Full Text Available BACKGROUND: Recent studies suggest that human auditory perception follows a prolonged developmental trajectory, sometimes continuing well into adolescence. Whereas both sensory and cognitive accounts have been proposed, the development of the ability to base current perceptual decisions on prior information, an ability that strongly benefits adult perception, has not been directly explored. Here we ask whether the auditory frequency discrimination of preschool children also improves when given the opportunity to use previously presented standard stimuli as perceptual anchors, and whether the magnitude of this anchoring effect undergoes developmental changes. METHODOLOGY/PRINCIPAL FINDINGS: Frequency discrimination was tested using two adaptive same/different protocols. In one protocol (with-reference, a repeated 1-kHz standard tone was presented repeatedly across trials. In the other (no-reference, no such repetitions occurred. Verbal memory and early reading skills were also evaluated to determine if the pattern of correlations between frequency discrimination, memory and literacy is similar to that previously reported in older children and adults. Preschool children were significantly more sensitive in the with-reference than in the no-reference condition, but the magnitude of this anchoring effect was smaller than that observed in adults. The pattern of correlations among discrimination thresholds, memory and literacy replicated previous reports in older children. CONCLUSIONS/SIGNIFICANCE: The processes allowing the use of context to form perceptual anchors are already functional among preschool children, albeit to a lesser extent than in adults. Nevertheless, immature anchoring cannot fully account for the poorer frequency discrimination abilities of young children. That anchoring is present among the majority of typically developing preschool children suggests that the anchoring deficits observed among individuals with dyslexia represent a
In-pile and out-of-pile testing of a molybdenum-uranium dioxide cermet fueled themionic diode
Diianni, D. C.
1972-01-01
The behavior of Mo-UO2 cermet fuel in a diode for thermionic reactor application was studied. The diode had a Mo-0.5 Ti emitter and niobium collector. Output power ranged from 1.4 to 2.8 W/cm squared at emitter and collector temperatures of 1500 deg and 540 C. Thermionic performance was stable within the limits of the instrumentation sensitivity. Through 1000 hours of in-pile operation the emitter was dimensionally stable. However, some fission gases (15 percent) leaked through an inner clad imperfection that occurred during fuel fabrication.
Unmanned Aerial Vehicle Use for Wood Chips Pile Volume Estimation
Mokroš, M.; Tabačák, M.; Lieskovský, M.; Fabrika, M.
2016-06-01
The rapid development of unmanned aerial vehicles is a challenge for applied research. Many technologies are developed and then researcher are looking up for their application in different sectors. Therefore, we decided to verify the use of the unmanned aerial vehicle for wood chips pile monitoring. We compared the use of GNSS device and unmanned aerial vehicle for volume estimation of four wood chips piles. We used DJI Phantom 3 Professional with the built-in camera and GNSS device (geoexplorer 6000). We used Agisoft photoscan for processing photos and ArcGIS for processing points. Volumes calculated from pictures were not statistically significantly different from amounts calculated from GNSS data and high correlation between them was found (p = 0.9993). We conclude that the use of unmanned aerial vehicle instead of the GNSS device does not lead to significantly different results. Tthe data collection consumed from almost 12 to 20 times less time with the use of UAV. Additionally, UAV provides documentation trough orthomosaic.
Noise and pile-up in liquid sampling calorimeters
International Nuclear Information System (INIS)
The design and construction of detectors for the SSC presents new challenges and requires electronics of priorly unavailable performance. Most detector elements produce minute signals which can be lost in the ever present noise from thermal fluctuation and the finite charge of the electron. The author presents in these notes a pedagogical introduction to noise and pile-up, as applicable to liquid sampling calorimeters, beginning with a brief, only descriptive, introduction to amplifiers and the physical origins of noise. He then studies the particular case of noise in charge measurements, in particular for calorimeters, where parallel noise is usually negligible. By a physical example he discusses optimal filtering, proving that gaussian filters are not optimal. The scaling laws of noise versus source capacitance and filter bandwidth or shaping time, are emphasized. An explicit example for pulse shapes peaking at 1 μs is computed and extrapolated to 0.1 μs, more appropriate for an SSC detector. Solutions for the several problems arising at short shaping times are discussed and the conditions for optimal preamp-detector matching (for minimum noise) are derived. He also briefly discusses pile-up and its scaling laws. Correlations between signal samples at different times are considered and computed for an example. Correlations are necessary to compute the noise in signals reconstructed from sampling
In-Pile Thermal Conductivity Measurement Method for Nuclear Fuels
Energy Technology Data Exchange (ETDEWEB)
Joy L. Rempe; Brandon Fox; Heng Ban; Joshua E. Daw; Darrell L. Knudson; Keith G. Condie
2009-08-01
Thermophysical properties of advanced nuclear fuels and materials during irradiation must be known prior to their use in existing, advanced, or next generation reactors. Thermal conductivity is one of the most important properties for predicting fuel and material performance. A joint Utah State University (USU) / Idaho National Laboratory (INL) project, which is being conducted with assistance from the Institute for Energy Technology at the Norway Halden Reactor Project, is investigating in-pile fuel thermal conductivity measurement methods. This paper focuses on one of these methods – a multiple thermocouple method. This two-thermocouple method uses a surrogate fuel rod with Joule heating to simulate volumetric heat generation to gain insights about in-pile detection of thermal conductivity. Preliminary results indicated that this method can measure thermal conductivity over a specific temperature range. This paper reports the thermal conductivity values obtained by this technique and compares these values with thermal property data obtained from standard thermal property measurement techniques available at INL’s High Test Temperature Laboratory. Experimental results and material properties data are also compared to finite element analysis results.
Evaluation of Candidate In-Pile Thermal Conductivity Techniques
Energy Technology Data Exchange (ETDEWEB)
B. Fox; H. Ban; J. Daw; K. Condie; D. Knudson; J. Rempe
2009-05-01
Thermophysical properties of materials must be known for proper design, test, and application of new fuels and structural properties in nuclear reactors. In the case of nuclear fuels during irradiation, the physical structure and chemical composition change as a function of time and position within the rod. Typically, thermal conductivity changes, as well as other thermophysical properties being evaluated during irradiation in a materials and test reactor, are measured out-of-pile in “hot-cells.” Repeatedly removing samples from a test reactor to make out-of-pile measurements is expensive, has the potential to disturb phenomena of interest, and only provide understanding of the sample's end state at the time each measurement is made. There are also limited thermophysical property data for advanced fuels. Such data are needed for the development of next generation reactors and advanced fuels for existing nuclear plants. Having the capacity to effectively and quickly characterize fuels and material properties during irradiation has the potential to improve the fidelity of nuclear fuel data and reduce irradiation testing costs.
In pile AISI 316L. Low cycle fatigue. Final report
International Nuclear Information System (INIS)
In pile testing of the effect of neutron irradiation on the fatigue life of the reference material AISI 316L was performed in the framework of the European fusion technology program. The overall programme, carried out at SCK CEN (Mol,Belgium), exists of two instrumented rigs for low cycle fatigue testing, which were consecutively loaded in the BR-2 reactor during periods Jan (94) June (94) and Aug (94)-Dec(94). In each experiment, two identical samples were loaded by means of a pneumatically driven system. The samples were instrumented with thermocouples, strain gages, linear variable displacement transducers, and activation monitors. The experimental conditions are given. Type of fatigue test: load controlled, symmetric, uniaxial, triangular wave shape; stress range: about 580 MPa; sample shape: hourglass, diameter 3.2 mm, radius 12.5 mm; environment: NaK (peritectic); temperature: 250 C; maximum dpa value up to fracture: 1.7. Two of four samples were broken (one in each experiment) after having experienced 17 419 respectively 11 870 stress cycles. These new data points confirm earlier results from pile fatigue tests: irradiation causes no degradation of fatigue life of AISI 316L steel, at least for the parameters corresponding to these experiments
Institute of Scientific and Technical Information of China (English)
周文权; 冷伍明; 阮波; 杨奇
2014-01-01
On the basis of considering the interaction between the pile and soil,the formation process and corre-sponding conditions of soil arch were analyzed to determine the reasonable pile spacing.According to the equilib-rium condition that the side friction force exerted on the pile is equal to the landslide thrust force,soil arch in the pile side and soil arch behind the pile were proposed and existed at the same time.The total arch thickness e-quates to the sum of above two soil arch.On this basis,the soil arch model under pressure was established with the interaction of landslide thrust and anti-slide pile being taken into consideration,by which the computational formula of critical pile spacing was derived.The calculation results show the reasonability and validity through examples by considering the effect of lateral soil arch and soil arch behind the pile simultaneously.The results show that it is reasonable to take into account the pile side arch and the soil arch behind the pile at the same time.%在考虑桩土相互作用的基础上，对确定合理桩间距的土拱的形成过程和成拱条件进行分析。根据桩受到的侧摩阻力等于桩间滑坡推力的平衡条件，提出同时存在桩侧土拱和桩后土拱，其拱厚为桩侧实际拱厚和桩后有效拱厚之和，在此基础上建立滑坡推力与抗滑桩相互作用的土拱受力模型，推导出临界桩间距的计算公式，最后通过算例进行验证，计算结果较为合理。研究结果表明：同时考虑桩侧土拱和桩后土拱比较合理。
Effects of Anchor Bolts Failures in Steam Explosion Analyses
Energy Technology Data Exchange (ETDEWEB)
Kim, Seung Hyun; Chang, Yoon-Suk [Kyung Hee University, Yongin (Korea, Republic of); Song, Sungchu; Cho, Yong-Jin [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)
2015-05-15
Steam explosion may occur in a nuclear power plant by molten core-coolant interactions when the external reactor vessel cooling strategy is failed. This phenomenon can threat the integrity of reactor cavity, penetration piping and support structures. Even though extensive researches have been performed to predict influences of the steam explosion, due to complexity of physical phenomena and environmental thermal hydraulic conditions, it is remained as one of possible hazards. A steam explosion can cause intensive and rapid heat transfer, and lead to the formation of pressure waves and production of missiles that may endanger surrounding reactor cavity wall and associate components due to resulting dynamic effects. The goal of this research is to examine structural integrity of RPV (Reactor Pressure Vessel) support structures and anchor bolts under typical ex-vessel steam explosion conditions through FE analyses. Particularly, influence due to the failure of anchor bolts connecting RPV and support structures was evaluated. In this paper, influence of RPV and support structure due to the anchor bolt failure were evaluated under typical steam explosion conditions and the following conclusions were derived. The highest maximum stresses were calculated at the support structures under the steam explosion condition with the SVF and anchor bolts non-failure. The all stress values did not exceed their yield strengths. The displacements were high under anchor bolt failure conditions. However, the vertical movements of major components were small comparing to the overall dimensions of them.
Effect of relative pile’s stiffness on lateral pile response under loading of large eccentricity
DEFF Research Database (Denmark)
Zania, Varvara; Hededal, Ole; Klinkvort, R.T.
2015-01-01
The wide application of monopiles as foundations for offshore wind turbines has raised the issue of the suitability of the p –y curves proposed by API for lateral pile loading, since the latter were developed after full-scale tests on flexible and slender piles. This study investigates the role of...
In-Situ Test and Numerical Analysis of Bore Pressure on Sheet-Pile Groin
Institute of Scientific and Technical Information of China (English)
XU Chang-jie; CAI Yuan-qiang; XUAN Wei-li; CHEN Hai-jun; SONG Yang
2006-01-01
An in-situ test of bore pressure on a sheet-pile groin is carried out to investigate the characteristics of the bore pressure of tide in the Qian-tang River. The histories of bore pressure and the rule of the distribution of bore pressure on the sheet-pile groin are obtained through the test, which shows that the bore pressure on the sheet-pile groin are varies with time and space. The peak value of bore pressure on sheet-pile groin at different heights occurs almost at the same time. The vertical distribution of bore pressure on the sheet-pile groin is linear above the still water level. The maximum bore pressure on the sheet-pile groin occurs at the still water level. Then a numerical method is also used to further study the characteristics of bore pressure. The standard κ-ε turbulence model and VOF (volume of fluid) method for surface tracking are used to simulate the bore against the sheet-pile groin. The numerical results show flow fields, the position of free surface and time history and spatial distribution of bore pressure on the sheet-pile groin. The numerical and test results show good agreement.
Comparison between Dynamic Responses of Hollow and Solid Piles for Offshore Wind Turbine Foundations
DEFF Research Database (Denmark)
Bayat, Mehdi; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo
2013-01-01
dynamic behavior of soil and interaction between soil and piles. To avert damage to offshore foundation, it becomes necessary to identify and quantify the soil-structure interaction and the related damping effects on the system. In this study, a single pile is investigated by means of boundary integral...
Time scale of scour around a pile in combined waves and current
DEFF Research Database (Denmark)
Petersen, Thor Ugelvig; Sumer, B. Mutlu; Fredsøe, Jørgen
The time scale of the scour process around a circular vertical pile is studied in combined waves and current. A series of tests were carried out in a flume with pile diameters 40 mm and 75 mm, in both steady current, waves and combined waves and current. In the combined wave and current flow regime...
In-situ grouting of uranium-mill-tailings piles: an assessment
International Nuclear Information System (INIS)
Passage in 1978 of the Uranium Mill Tailings Radiation Control Act (UMTRCA) initiated a program of remedial action for 22 existing mill tailings piles generated in the period 1940 to 1970 as part of the nation's defense and nuclear power programs. The presence of these piles poses potential health and environmental contamination concerns. Possible remedial actions proposed include multilayer covers over the piles to reduce water infiltration, reduce radon gas releases, and reduce airborne transport of tailings fines. In addition, suggested remedial actions include (1) the use of liners to prevent groundwater contamination by leachates from the piles and (2) chemical stabilization of the tailings to retain the radioactive and nonradioactive sources of contamination. Lining of the piles would normally be applicable only to piles that are to be moved from their present location such that the liner could be placed between the tailings and the groundwater. However, by using civil engineering techniques developed for grouting rocks and soils for strength and water control, it may be possible to produce an in situ liner for piles that are not to be relocated. The Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project Office requested that ORNL assess the potential application of grouting as a remedial action. This report examines the types of grouts, the equipment available, and the costs, and assesses the possibility of applying grouting technology as a remedial action alternative for uranium mill tailings piles
Small-Scale Cyclic Tests on Nonslender Piles Situated in Sand
DEFF Research Database (Denmark)
Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo
In the period from August 2011 till October 2011 a series of small-scale tests on pile foundations has been conducted at Aalborg University. In all the tests, the piles have been exposed to cyclic loading consisting of 20-25 load cycles and all the tests have been conducted in a pressure tank. Th...
Small-Scale Quasi-Static Tests on Non-Slender Piles Situated in Sand
DEFF Research Database (Denmark)
Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo
In the period from February 2009 till March 2011 a series of small-scale tests on pile foundations has been conducted at Aalborg University. In all the tests the piles have been exposed to quasi-static loading and all the tests have been conducted in a pressure tank. The objective of the tests ha...
Backfilling of a Scour Hole around a Pile in Waves and Current
DEFF Research Database (Denmark)
Sumer, B. Mutlu; Petersen, Thor Ugelvig; Locatelli, Luca;
2013-01-01
This paper presents the results of an experimental investigation of the backfilling of scour holes around circular piles. Scour holes around a pile are generated either by a current or a wave. Subsequently, the flow climate is changed from current to wave, combined waves and current, or wave to a...
A performance case study of energy pile foundation at Rosborg Gymnasium (Denmark)
DEFF Research Database (Denmark)
Pagola, Maria Alberdi; Jensen, Rasmus Lund; Poulsen, Søren Erbs
2016-01-01
The Rosborg Gymnasium building in Vejle (Denmark) is partially founded on 200 foundation pile heat exchangers (energy piles). The thermo-active foundation has supplemented the heating and free cooling needs of the building since 2011 (4,000 m2 living area). Operational data from the ground source...
Pile-up correction by Genetic Algorithm and Artificial Neural Network
International Nuclear Information System (INIS)
Pile-up distortion is a common problem for high counting rates radiation spectroscopy in many fields such as industrial, nuclear and medical applications. It is possible to reduce pulse pile-up using hardware-based pile-up rejections. However, this phenomenon may not be eliminated completely by this approach and the spectrum distortion caused by pile-up rejection can be increased as well. In addition, inaccurate correction or rejection of pile-up artifacts in applications such as energy dispersive X-ray (EDX) spectrometers can lead to losses of counts, will give poor quantitative results and even false element identification. Therefore, it is highly desirable to use software-based models to predict and correct any recognized pile-up signals in data acquisition systems. The present paper describes two new intelligent approaches for pile-up correction; the Genetic Algorithm (GA) and Artificial Neural Networks (ANNs). The validation and testing results of these new methods have been compared, which shows excellent agreement with the measured data with 60Co source and NaI detector. The Monte Carlo simulation of these new intelligent algorithms also shows their advantages over hardware-based pulse pile-up rejection methods.
Pile-up correction by Genetic Algorithm and Artificial Neural Network
Energy Technology Data Exchange (ETDEWEB)
Kafaee, M. [Faculty of Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Saramad, S. [Faculty of Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)], E-mail: ssaramad@aut.ac.ir
2009-08-21
Pile-up distortion is a common problem for high counting rates radiation spectroscopy in many fields such as industrial, nuclear and medical applications. It is possible to reduce pulse pile-up using hardware-based pile-up rejections. However, this phenomenon may not be eliminated completely by this approach and the spectrum distortion caused by pile-up rejection can be increased as well. In addition, inaccurate correction or rejection of pile-up artifacts in applications such as energy dispersive X-ray (EDX) spectrometers can lead to losses of counts, will give poor quantitative results and even false element identification. Therefore, it is highly desirable to use software-based models to predict and correct any recognized pile-up signals in data acquisition systems. The present paper describes two new intelligent approaches for pile-up correction; the Genetic Algorithm (GA) and Artificial Neural Networks (ANNs). The validation and testing results of these new methods have been compared, which shows excellent agreement with the measured data with {sup 60}Co source and NaI detector. The Monte Carlo simulation of these new intelligent algorithms also shows their advantages over hardware-based pulse pile-up rejection methods.
R. Ananda Kumar; Dr. C. Selvamony; A. Seeni; Dr. T. R. Sethuraman
2015-01-01
Abstract Retrofitting works are immensely essential for deteriorated and damaged structures in Engineering and Medical fields in order to keep or return to the originality for safe guarding the structures and consumers. In this paper different types of methods of retrofitting review notes are given based on the experimental numerical and analytical methods results on strengthening the Reinforced cement concrete RCC structures including RCC piles. Soil-pile interaction on axial load lateral lo...
Directory of Open Access Journals (Sweden)
M. A. Lisnevskyi
2015-08-01
Full Text Available Purpose. Taking into consideration that the bearing capacity of the foundation may be insufficient, in the study it is assumed that pile foundation can be used to reduce the impact of the construction of new retaining structures on roads and railways near the existing buildings or in areas of dense urban development and ensure the stability of the foundation. To reduce the volume of excavation it is necessary to choose the economic structure of the retaining wall. To do this, one should explore stress-strain state (SSS of the retaining walls, to develop methods to improve their strength and stability, as well as to choose the most appropriate method of their analysis. Methodology. In the design of retaining walls foundation mat and piles are considered as independent elements. Since the combined effect of the retaining wall, piles and foundation mat as well as the effect of soil or rock foundation on the structure are considered not fully, so there are some limitations in the existing design techniques. To achieve the purpose the box tests of retaining walls models without piles and with piles for studying their interaction with the surrounding soil massif were conducted. Findings. Laboratory simulation of complex systems «surrounding soil – retaining wall – pile» was carried out and on the basis of the box test results were analyzed strains and its main parameters of the stress-strain state. Analysis of the results showed that the structure of a retaining wall with piles is steady and stable. Originality. So far, in Ukraine has not been carried out similar experimental box tests with models of retaining walls in such combinations. In the article has been presented unique photos and test results, as well as their analysis. Practical value. Using the methodology of experimental tests of the retaining wall models with piles and without them gives a wider opportunity to study stress-strain state of such structures.
Free vibration of semi-rigid connected Reddy–Bickford piles embedded in elastic soil
Indian Academy of Sciences (India)
Yusuf Yesilce; Hikmet H Catal
2008-12-01
The literature on free vibration analysis of Bernoulli–Euler and timoshenko piles embedded in elastic soil is plenty, but that of Reddy–Bickford piles partially embedded in elastic soil with/without axial force effect is fewer. The soil that the pile partially embedded in is idealized by Winkler model and is assumed to be two-layered. The pile part above the soil is called the ﬁrst region and the parts embedded in the soil are called the second and the third region, respectively. It is assumed that the behaviour of the material is linear-elastic, that axial force along the pile length to be constant and the upper end of the pile that is semi-rigid supported against rotation is modelled by an elastic spring. The governing differential equations of motion of the rectangular pile in free vibration are derived using Hamilton’s principle and Winkler hypothesis. The terms are found directly from the solutions of the differential equations that describe the deformations of the cross-section according to the high-order theory. The models have six degrees of freedom at the two ends, one transverse displacement and two rotations, and the end forces are a shear force and two end moments. Natural frequencies of the pile are calculated using transfer matrix and the secant method for non-trivial solution of linear homogeneous system of equations obtained due to values of axial forces acting on the pile, total and embedded lengths of the pile, the linear-elastic rotational restraining stiffness at the upper end of the pile and to the boundary conditions of the pile. Two different boundary conditions are considered in the study. For the ﬁrst boundary condition, the pile’s end at the ﬁrst region is semi-rigid connected and not restricted for horizontal displacement and the end at the third region is free and for the second boundary condition, the pile’s end at the ﬁrst region is semi-rigid connected and restricted for horizontal displacement and the end at the
Performance of pile-up mitigation techniques for jets in pp collisions with the ATLAS detector
Testa, M.
2016-07-01
The large rate of multiple simultaneous proton-proton interactions, or pile-up, generated by the Large Hadron Collider in Run 1 required the development of many new techniques to mitigate the adverse effects of these conditions. The methods employed to correct for the impact of pile-up on jet energy, shapes and multiplicity with the ATLAS detector are presented here. They include energy correction techniques based on estimates of the average pile-up energy density and jet-to-vertex association techniques. Extensions of these methods to reduce the impact of pile-up on jet shapes use both subtraction and grooming procedures. Prospects for pile-up suppression at the HL-LHC are also shown.
Determination of load-transfer parameters of single piles axially loaded
Directory of Open Access Journals (Sweden)
Yaich Achour N
2014-04-01
Full Text Available Modern buildings require more use of the deep foundations including piles. The good perception of the behavior of piles and the knowledge of their bearing capacity is essential for a rational use. The present work focuses on the behavior of single pile under vertical loads in clay and sand soils. Thus, an approach to semi-empirical calculations load transfer as well as finite element modeling are used in order to determine the curve loading / sag at the head of pile and deduce the calculation parameters. This study has allowed predicting the load curves piles, knowing their geometric properties and some test results of in-situ soil (CPT, PMT and SPT.
Evaluation of an Improved Technique for Geosynthetic-Reinforced and Pile-Supported Embankment
Directory of Open Access Journals (Sweden)
Jun Zhang
2015-01-01
Full Text Available With a large number of applications of conventional technique for geosynthetic-reinforced and pile-supported (GRPS embankment (called CT embankment, many deficiencies have been exposed. In view of the deficiencies, an improved technique, fixed-geosynthetic-reinforced and pile-supported embankment (called FGT embankment, is developed. To investigate the performance of the FGT embankment, the comparison analyses and parametric studies are conducted by Finite Element Method (FEM. The influencing factors investigated include elastic modulus of soil, tensile stiffness of geosynthetics, pile length, pile spacing, and pile elastic modulus. In addition, the cost evaluation for the FGT embankment and CT embankment is also made. The results show that the FGT embankment can significantly reduce the settlement and differential settlement, enhance the stability, and provide an economical and effective measure for the construction of high embankment at the bridge approach.
Study of the light emitted in the moderation of a heavy-water pile
International Nuclear Information System (INIS)
During the running of a reactor which uses water as a neutron moderator, a bluish light is seen to appear inside the liquid. A detailed study of this radiation, undertaken on the Fontenay-aux-Roses pile, has shown that the spectrum is identical with that which characterises the light produced by the Cerenkov effect. The light intensity as a function of the pile power grows exponentially as a function of time when the pile diverges, with a lifetime equal to that of the rise in power. An examination of the various particles present in the pile has led to the conclusion that only electrons with an energy greater than 260 keV con produce the Cerenkov light. The light source thus produced is about 2.106 photons/cm2 of water, when the pile power equals 1 watt. (author)
Catastrophic model for stability analysis of high pile-column bridge pier
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism. Based on the catastrophe theory, the cusp catastrophe model of higher pile-column bridge pier was established by the determination of its potential function and bifurcation set equation, the necessary instability conditions of high pile-column bridge pier were deduced, and the determination method for column-buckling and lateral displacement of high pile-column bridge pier was derived. The comparison between the experimental and calculated results show that the calculated curves agree with testing curves and the method is reasonable and effective.
Comparative analysis of seismic response characteristics of pile-soil-structure interaction system
Kong, Desen; Luan, Maotian; Wang, Weiming
2006-01-01
The study on the earthquake-resistant performance of a pile-soil-structure interaction system is a relatively complicated and primarily important issue in civil engineering practice. In this paper, a computational model and computation procedures for pile-supported structures, which can duly consider the pile-soil interaction effect, are established by the finite element method. Numerical implementation is made in the time domain. A simplified approximation for the seismic response analysis of pile-soil-structure systems is briefly presented. Then a comparative study is performed for an engineering example with numerical results computed respectively by the finite element method and the simplified method. Through comparative analysis, it is shown that the results obtained by the simplified method well agree with those achieved by the finite element method. The numerical results and findings will offer instructive guidelines for earthquake-resistant analysis and design of pile-supported structures.
Comparative Analysis of Seismic Response Characteristics of Pile-Soil-Structure Interaction System
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The study on the earthquake-resistant performance of a pile-soil-structure interaction system is a relatively complicated and primarily important issue in civil engineering practice. In this paper, a computational model and computation procedures for pile-supported structures, which can duly consider the pile-soil interaction effect, are established by the finite element method. Numerical implementation is made in the time domain. A simplified approximation for the seismic response analysis of pile-soil-structure systems is briefly presented. Then a comparative study is performed for an engineering example with numerical results computed respectively by the finite element method and the simplified method. Through comparative analysis, it is shown that the results obtained by the simplified method well agree with those achieved by the finite element method. The numerical results and findings will offer instructive guidelines for earthquake-resistant analysis and design of pile-supported structures.
Numeric simulation analysis of load-settlement relation of pile in layer foundation
Institute of Scientific and Technical Information of China (English)
WANG You-qing
2006-01-01
Considering the level distribution of soil layers, the soils surrounding pile are simulated with level finite layer elements. Supposing that the vertical deformation of the soil elements surrounding pile varies in the form of exponent function with radial distance, and considering the nonlinear constitutive relation of stress and strain, the stiffness matrix is established. The mechanics behavior of the pile-soil interface is simulated with a nonlinear interface element. This method can truly express the behavior of the pile-soil system. The load-settlement relation Q-S curves of two big diameter prototype piles on bearing test are analyzed, and satisfying results are obtained. This method is reasonable in theory and feasible in engineering.
Settlement Analysis of Saturated Tailings Dam Treated by CFG Pile Composite Foundation
Directory of Open Access Journals (Sweden)
Jinxing Lai
2016-01-01
Full Text Available Cement fly ash gravel (CFG pile composite foundation is an effective and economic foundation treatment approach, which is significant to building foundation, subgrade construction, and so forth. The present paper aims at investigating the settlement behaviors of saturated tailings dam soft ground under CFG pile composite foundation treatment, in which FEM and laboratory model test were utilized. The proposed findings demonstrate that CFG pile treatment is effective in reinforcing saturated tailings dam and loading has little influence on settlement of soil between piles. The variation of soil between piles settlement in FEM has a good agreement with the laboratory model test. Additionally, the cushion deformation modulus has a small effect on the composite foundation settlement, although the cushion thickness will generate certain influence on the settlement distribution of the composite foundation.
Optical Fiber Grating Sensor for Force Measurement of Anchor Cable
Institute of Scientific and Technical Information of China (English)
JIANG Desheng; FU Jinghua; LIU Shengchun; SUI Lingfeng; FU Rong
2006-01-01
The development of the sensor suitable for measuring large load stress to the anchor cable becomes an important task in bridge construction and maintenance. Therefore, a new type of optical fiber sensor was developed in the laboratory - optical fiber grating sensor for force measurement of anchor cable (OFBFMAC). No similar report about this kind of sensor has been found up to now in China and other countries. This sensor is proved to be an effective way of monitoring in processes of anchor cable installation, cable cutting, cable force regulation, etc, with the accurate and repeatable measuring results. Its successful application in the tie bar cable force safety monitoring for Wuhan Qingchuan bridge is a new exploration of optical fiber grating sensing technology in bridge tie bar monitoring system.
Plate anchored stirrup; Pureto teichakugata sendan hokyo tekkin
Energy Technology Data Exchange (ETDEWEB)
Nakamura, T.; Tanaka, Y.; Nakano, K.; Yamamoto, T. [Taisei Construction Co. Ltd., Tokyo (Japan)
1998-09-01
After the Great Hanshin Earthquake, the use of edge form of stirrups of semicircular hook or acute-angled hook which functions sufficiently even after exfoliation of concrete cover is proposed instead of right angle hook. However, when these stirrups are used in plate structures requiring hooks on two ends or in columns as connection reinforcement of hoop, the construction of these stirrups is so complicated that brings higher cost. The authors proposes stirrups to anchor by plate for stirrups of planar members. Anchorage capacity of these plate anchored stirrups and hooks after exfoliation of concrete cover was examined by experiments and the anchorage capacity was confirmed to be larger than that of semicircular hooks. The plate anchored stirrups are effective and easy to construct with low cost. 7 refs., 13 figs., 4 tabs.
Proteomic analysis of GPI-anchored membrane proteins
DEFF Research Database (Denmark)
Jung, Hye Ryung; Jensen, Ole Nørregaard
2006-01-01
humans. GPI-APs confer important cellular functions as receptors, enzymes and scaffolding molecules. Specific enzymes and detergent extraction methods combined with separation technologies and mass spectrometry permit proteomic analysis of GPI-APs from plasma membrane preparations to reveal cell......Glycosyl-phosphatidyl-inositol-anchored proteins (GPI-APs) represent a subset of post-translationally modified proteins that are tethered to the outer leaflet of the plasma membrane via a C-terminal GPI anchor. GPI-APs are found in a variety of eukaryote species, from pathogenic microorganisms to...
Addition of lipid substituents of mammalian protein glycosylphosphoinositol anchors.
Singh, N.; Zoeller, R A; Tykocinski, M. L.; Lazarow, P B; Tartakoff, A M
1994-01-01
A single metabolic path leading to synthesis of ether lipids is known in animal cells, the major products of which are plasmalogens. To learn whether this peroxisomal path is also responsible for the synthesis of base-resistant lipid components of glycosylphosphoinositol (GPI)-anchored membrane proteins, we have investigated the structure of anchor precursor mannolipids both in wild-type cells (CHO-K1 and a macrophage-like line, RAW 264.7) and in two corresponding mutant cells in which ether ...
PULLOUT CAPACITY OF HORIZONTAL AND INCLINED PLATE ANCHORS IN CLAYEY SOILS
Directory of Open Access Journals (Sweden)
BALESHWAR SINGH
2011-11-01
Full Text Available Soil anchors are required to withstand uplift or lateral forces acting on the foundations of structures constructed both in land and offshore sites. Plate anchoring system is being increasingly used to moor floating structures for the exploration and development of oil and gas fields. In this study, various experimental,theoretical and numerical approaches for estimation of pullout capacity of horizontal and inclined plate anchors in clayey soils are reviewed. A comparative analysis of the ultimate capacity is then carried out for plate anchors embedded in clayey soils by varying embedment ratio for horizontal anchors and by varying inclination angle for inclined plate anchors.
Current status of frameless anchored IUD for immediate intracesarean insertion.
Wildemeersch, Dirk; Goldstuck, Norman D; Hasskamp, Thomas
2016-01-01
Immediate postpartum intrauterine device (IUD) insertion deserves great attention as it can provide immediate, timely and convenient contraception plus the added benefit of preventing repeat unintended pregnancies. Although women post vaginal delivery can benefit from immediate post-placenta contraception, women undergoing Cesarean section clearly need contraception, as an inter-delivery interval shorter than 18 months places them at a high risk for uterine rupture. The main drawback of currently available framed IUD devices for immediate postpartum insertion of an IUD is their high expulsion and displacement rates when inserted immediately postpartum after both vaginal and Cesarean delivery. Current research suggests that a brief window of opportunity exists of 10 minutes for insertion of conventional IUDs after which time expulsion rates both immediately and over time are greatly enhanced. This paper summarizes the current research conducted to overcome the expulsion problems associated with conventional T-shaped devices as well as through the use of an anchored frameless device. In the 1970s and 1980s, attempts were made to solve the expulsion problem by modifying existing devices, such as adding absorbable sutures (Delta-T) or additional appendages. These attempts proved to be clinically unsuccessful as the catgut suture added to the transverse arms did not provide sufficient resistance to prevent downward displacement and expulsion. An anchoring technique to suspend a copper IUD to the fundus of the uterus was developed in Belgium in the 1980s and has been the subject of extensive ongoing clinical research since 1985. Recently the frameless copper releasing anchor IUD, GyneFix, has been tested for postplacental insertion. Initially, the anchor was modified by the inclusion of a biodegradable cone which was added below the anchoring knot. Clinical studies confirmed the adequacy of this approach suggesting that it was technically possible to anchor an IUD
Catalyse électro-microbienne dans les piles à combustible
Dumas, Claire
2007-01-01
Les piles à combustible microbiennes (PACM) sont des systèmes qui assurent la conversion directe de matières organiques en énergie électrique en utilisant des biofilms bactériens comme catalyseur des réactions électrochimiques. Cette étude vise à améliorer la compréhension des mécanismes de transfert électronique entre les bactéries adhérées et les électrodes, ainsi qu'à optimiser la production électrique des PACMs en explorant et caractérisant différents matériaux d'électrodes. Les expérienc...
Full Wave Solution for Hydrodynamic Behaviors of Pile Breakwater
Institute of Scientific and Technical Information of China (English)
ZHU Da-tong
2013-01-01
Rayleigh expansion is used to study the water-wave interaction with a row of pile breakwater in finite water depth.Evanescent waves,the wave energy dissipated on the fluid resistance and the thickness of the breakwater are totally included in the model.The formulae of wave reflection and transmission coefficients are obtained.The accuracy of the present model is verified by a comparison with existing results.It is found that the predicted wave reflection and transmission coefficients for the zero order are all highly consistent with the experimental data (Hagiwara,1984;Isaacson et al.,1998) and plane wave solutions (Zhu,2011).The losses of the wave energy for the fluid passing through slits play an important role,which removes the phenomena of enhanced wave transmission.
Electrochemical reduction of water. Development of a flat cell pile
International Nuclear Information System (INIS)
The working conditions of an electrolyser are described. Great variations of water vapor concentrations through the battery makes us advocate for piling up flat cells working under a constant potential. A 50 cm2 half cathodic cell has been fabricated. The solid electrolyte is made of zirconia (0,91 ZrO2, 0,09 Y2O3) associated with an embedded layer of nickel powder as the cathode. The disc is supported by an honeycomb shaped ceramic which is covered by a layer of nickel. The most promising method for solid electrolyte fabrication is the powder compaction and sintering process. The plasma jet projection gave interesting results and can be considered as an alternative process. A test set working at 8500C is on the way. It will give informations on the stability of the prepared parts and allow us to measure the characteristics of the planar cell
Simulations of impacts on rubble-pile asteroids
Deller, J.; Snodgrass, C.; Lowry, S.; Price, M.; Sierks, H.
2014-07-01
Rubble-pile asteroids can contain a high level of macroporosity. For some asteroids, porosities of 40 % or even more have been measured [1]. While little is known about the exact distribution of the voids inside rubble-pile asteroids, assumptions have to be made for the modeling of impact events on these bodies. Most hydrocodes do not distinguish between micro- and macroporosity, instead describing brittle material by a constitutive model as homogeneous. We developed a method to model rubble-pile structures in hypervelocity impact events explicitly. The formation of the asteroid is modelled as a gravitational aggregation of spherical `pebbles', that form the building blocks of our target. This aggregate is then converted into a high-resolution Smoothed Particle Hydrodynamics (SPH) model, which also accounts for macroporosity inside the pebbles. We present results of a study that quantifies the influence of our model parameters on the outcome of a typical impact event of two small main-belt asteroids. The existence of void space in our model increases the resistance against collisional disruption, a behavior observed before [2]. We show that for our model no a priori knowledge of the rubble-pile constituents in the asteroid is needed, as the choice of the corresponding parameters does not directly correlate with the impact outcome. The size distribution of the pebbles used as building blocks in the formation of an asteroid is only poorly constrained. As a starting point, we use a power law N(>r) ∝ r^α to describe the distribution of radii of the pebbles. Reasonable values for the slope α range around α=-2.5, as found in the size distribution of main-belt objects [3,4]. The cut-off values for pebbles, r_{min} and r_{max} are given by practical considerations: In the SPH formalism, properties are represented by weighted averages of particles within their smoothing length h, preventing the resolution of structures below that scale. Using spheres with radius in the
Piling Up Pillar[5]arenes To Self-Assemble Nanotubes.
Nierengarten, Iwona; Guerra, Sebastiano; Ben Aziza, Haifa; Holler, Michel; Abidi, Rym; Barberá, Joaquín; Deschenaux, Robert; Nierengarten, Jean-François
2016-04-25
New liquid-crystalline pillar[5]arene derivatives have been prepared by grafting first-generation Percec-type poly(benzylether) dendrons onto the macrocyclic scaffold. The molecules adopt a disc-shaped structure perfectly suited for self-organization into a columnar liquid-crystalline phase. In this way, the pillar[5]arene cores are piled up, thus forming a nanotubular wire encased within a shell of peripheral dendrons. The capability of pillar[5]arenes to form inclusion complexes has been also exploited. Specifically, detailed binding studies have been carried out in solution with 1,6-dicyanohexane as the guest. Inclusion complexes have also been prepared in the solid state. Supramolecular organization into the Colh mesophase has been deduced from X-ray diffraction data and found to be similar to that observed within the crystal lattice of a model inclusion complex prepared from 1,4-dimethoxypillar[5]arene and 1,6-dicyanohexane. PMID:26888329
In-pile dosimetry. Report of a panel
International Nuclear Information System (INIS)
A serious difficulty in much experimental research work with research reactors is that of measuring accurately doses or neutron fluences in cases where these are an essential parameter. Even if accurate measurements are performed, it is still in most cases impossible to compare experimental results obtained in different types of reactors, because of the inadequacy of present methods and units to reflect the dependence of spectra and radiation composition on the induced processes. In view of this the International Atomic Energy Agency convened a Panel on in-pile dosimetry which was held from 13 to 17 July 1964 to review the present status of research and development work and to advise the Director General of the Agency on a possible programme in this field. The results of this Panel are published in the present Report. Although primarily intended as advice to the Agency, many aspects of the discussions and submitted status reports and papers were considered to be of such general interest that the Agency should make them available in published form. The papers have, however, been included only as summaries as they have, to a considerable extent, been incorporated in the Panel Report and recommendations. It is recognized that the International Commission on Radiological Units and Measurements (ICRU) has recommended a terminology for this field, but this is not yet in general use in many laboratories. Although this terminology is used in the Report of the Panel, no effort has been made to introduce it into the submitted status reports and summaries published here as it Is felt that there is no major risk of confusion. This publication should not be taken as a report on the Agency's programme in the field of in-pile dosimetry, although it serves as a basis on which to build such a program
Gerasev, P I
2002-01-01
It is considered that in Anacanthorinae, Markewitschiana and Pseudacolpenteron pavlovskii (Dactylogyridae s. s.) the anchors are absent originally. In the other dactylogyrids (s. l.) without anchors (Pseudacolpenteron ignotus; Acolpenteron; Anonchohaptor-Icelanchohaptor; Kritskyia-Telethecium-Pavanelliela) these structures are lost. In related genera Rhinoxenus and Nanotrema the dorsal pair of anchors is transformed into the "spikes"; in Heteronchocleidinae there is one anchor; in Trinigyrus and Schilbetrematoides are two anchors; and in Urogyrus three anchors are reduced. But in Rhinonaster, Cacatyocotyle, Callceostomella, Neocalseostoma elongatum and Pseudodactylogyridae the presence of one pair of ventral "peduncular" or "haptoral" anchors appear to be the original state. For Anacanthorinae and Dactylogyridae s. s. the presence of 18-16 hooks, original lacking of anchors, appearance of one pair of them, evolutionary development and subsequent reduction of these structures are characteristic. In the dactylogyrids (s. l.) having two pairs of anchors and 14 hooks, one pair of the anchors is present originally, then usually the second dorsal pair grows up, and finally, the reduction of a part of anchors or all the anchors is possible. In the 16-hooked dactylogyrids (s. l.) having two pairs of anchors (Tetraonchinea, Amphibdellainea, Neodactylodiscinea) the original lacking or reduction of the anchors is not reported. The author considers, that it is unwarranted to unite all dactylogyrids (s. l.) without anchors into the superorder Ananchorea Malmberg, 1990 or to postulate the original presence of the two pairs of ventral anchors in this group. It is also impossible to unit all dactylogyrids (s. l.) having 0-4 anchors and 18-14 hooks into Dactylogyridae sensu Boeger et Kritsky, 1993. PMID:12070963
Rebekah E Oliver; Tinker, Nicholas A.; Lazo, Gerard R.; Shiaoman Chao; Jellen, Eric N.; Martin L. Carson; Rines, Howard W; Donald E Obert; Lutz, Joseph D.; Irene Shackelford; Korol, Abraham B.; Charlene P. Wight; Gardner, Kyle M.; Jiro Hattori; Beattie, Aaron D
2013-01-01
A physically anchored consensus map is foundational to modern genomics research; however, construction of such a map in oat (Avena sativa L., 2n = 6x = 42) has been hindered by the size and complexity of the genome, the scarcity of robust molecular markers, and the lack of aneuploid stocks. Resources developed in this study include a modified SNP discovery method for complex genomes, a diverse set of oat SNP markers, and a novel chromosome-deficient SNP anchoring strategy. These resources wer...
Wave force on double cylindrical piles: a comparison between exact and finite difference solutions
Ali, Lotfollahi-Yaghin Mohammad; Mehdi, Moosavi Sayyid; Amin, Lotfollahi-Yaghin
2011-03-01
The wave force exerted on vertical piles of offshore structures is the main criterion in designing them. In structures with more than one large pile, the influence of piles on each other is one of the most important issues being concerned in past researches. An efficient method for determining the interaction of piles is introduced in present research. First the wave force is calculated by the exact method using the diffraction theory, then in the finite difference numerical method the force is calculated by adding the velocity potentials of each pile and integration of pressure on their surface. The results showed that the ratio of the wave force on each of the double piles to a single pile has a damped oscillation around unity in which the amplitude of oscillation decreases with the increase in the spacing parameter. Also different wave incident directions and diffraction parameters were used and the results showed that the numerical solution has acceptable accuracy when the diffraction parameter is larger than unity.
Case Study of CPT-based Design Methods for Axial Capacity of Driven Piles in Sand
DEFF Research Database (Denmark)
Thomassen, Kristina; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard
2012-01-01
loaded offshore driven piles in cohesionless soil has until now been the β-method given in API. The API-method is based on the effective overburden pressure at the depth in question. Previous studies show deviations between full-scale load test measurements of the axial pile capacity and the predictions...... found by means of the API-method. Compared to the test measurements, the API-method under-estimates the capacity of short piles (<20m) in dense sand, over-estimates the capacity of long piles in loose sand, and gives a shaft capacity less conservative for piles in tension than for piles in compression....... Thus, several CPT-based methods have been proposed for the design of offshore driven piles in cohesionless soil such as the UWA-05, ICP-05, and NGI-99 methods. This article treats a case study where the API-method as well as the UWA-05 and NGI-99 methods are compared using CPT-data from an offshore...
International Nuclear Information System (INIS)
Highlights: ► We performed TRTs for PHC energy piles with 3U- and W- shaped heat exchangers. ► We successfully predicted the monitored thermal behaviors in TRTs by 3D FE analyses. ► We evaluated thermal resistances of energy piles from TRT simulations. ► Thermal performance of the PHC energy pile in Korea was estimated to be efficient. ► Longer pipe was estimated to be beneficial not for base load but for peak load. -- Abstract: This paper presents an experimental and numerical study on evaluation of thermal response and performance of prototype precast-high strength concrete (PHC) energy pile. Short-term field thermal response tests (TRTs) were conducted for the PHC energy piles installed in partially saturated weathered granite soil deposit, in which two types of heat exchangers were considered: W and 3U-shaped heat exchangers. The TRTs were successfully simulated by three-dimensional finite element analyses employing quasi-steady-state convective heat transfer boundary condition. The numerical model was applied to simulate 3-day TRTs, and the simulation results were used for assessing effective thermal conductivity and thermal resistance. Besides, continuous and intermittent operation simulations of the energy piles were performed, and for the results of performance analyses, discussion was made to evaluate energy efficiency of the prototype PHC piles.
Crack initiation ahead of piled-up of dislocations emitted from a mode Ⅱ blunt crack
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
In situ tensile tests in a transmission electron microscope (TEM) show that dislocations emitted from a mode II crack tip will form a inverse piled-up group after equilibrium or a double piled-up group when they meet a obstruction, e.g., grain boundary or second phase. A microcrack can initiates in front of the piled-up group of dislocations. Micromechanics analysis shows that dislocations emitted from a mode II blunt crack tip can form a inverse piled-up or double piled-up group, depending upon the applied stress intensity factor KIIa, latticefriction stress and the distance of the obstruction from the crack tip L. The maximum normal stress in front of the double piled-up group which is located at the direction of €? Increases with the increase in the stress intensity KIIa and the obstruction site L, and the decrease in the friction stress . When it increases to equate the cohesive strength, a microcrack will initiate in front of the piled-up group.
Regressive approach for predicting bearing capacity of bored piles from cone penetration test data
Directory of Open Access Journals (Sweden)
Iyad S. Alkroosh
2015-10-01
Full Text Available In this study, the least square support vector machine (LSSVM algorithm was applied to predicting the bearing capacity of bored piles embedded in sand and mixed soils. Pile geometry and cone penetration test (CPT results were used as input variables for prediction of pile bearing capacity. The data used were collected from the existing literature and consisted of 50 case records. The application of LSSVM was carried out by dividing the data into three sets: a training set for learning the problem and obtaining a relationship between input variables and pile bearing capacity, and testing and validation sets for evaluation of the predictive and generalization ability of the obtained relationship. The predictions of pile bearing capacity by LSSVM were evaluated by comparing with experimental data and with those by traditional CPT-based methods and the gene expression programming (GEP model. It was found that the LSSVM performs well with coefficient of determination, mean, and standard deviation equivalent to 0.99, 1.03, and 0.08, respectively, for the testing set, and 1, 1.04, and 0.11, respectively, for the validation set. The low values of the calculated mean squared error and mean absolute error indicated that the LSSVM was accurate in predicting the pile bearing capacity. The results of comparison also showed that the proposed algorithm predicted the pile bearing capacity more accurately than the traditional methods including the GEP model.
Directory of Open Access Journals (Sweden)
Mohammad A. Assareh
2008-01-01
Full Text Available The operation for offshore oil has become an important issue in the recent years. Offshore platforms are some of those structures which are built to withstand environmental and accidental loads during oil exploitation operation. One of the most usual types of these platforms is the Jacket Type Offshore Platform (JTOP which can be divided into three important parts, which are Deck, Jacket and piles. In order to increase the safety, particular attention should be paid to earthquake excitations which are directly applied to the piles of these structures. Nonlinearity in piles and buckling of the struts are important issues which have to be considered by the designers of offshore platforms. The case of nonlinearity in piles and failure capture in these members has not effectively been covered by researchers. Incremental Dynamic Analysis (IDA is a powerful tool to assess the capacity of a structure upon seismic loads. In this paper incremental dynamic analysis has been implemented on single piles considering soil-pile interactions and free field site response. The use of nonlinear materials and lateral load resisting elements in the incremental dynamic analysis done in this paper has made it possible to get promising insights for incorporation of appropriate limit states and applications of performance based engineering. Special Engineering Demand Parameters (EDP and Intensity Measures (IM have been introduced for the single pile dynamic analysis in jacket type offshore platforms.
Institute of Scientific and Technical Information of China (English)
赖伟
2012-01-01
以广东沿海某城市火车站超大面积深厚软土采用桩网复合地基进行软土地基处理工程为例,利用FLAC3D数值分析软件,研究不同桩间距、桩帽宽度对桩身弯矩的影响。研究发现,桩间距的增大会使桩身弯矩增大,桩帽宽度的增大会减小桩身弯矩,但桩间距的变化对桩身弯矩的影响更明显。%Taking the treatment engineering by pile-net extra-large area at the railway station in a coastal city in composite foundation against the deep soft soil in Guangdong as the example, the influence of the pile spacing and the pile cap width on bending moment of the pile body is studied with FLAC3D numerical analysis software. The study findings include that the increment of pile spacing will give rise to the increment of bending moment, while the increment of pile cap width will reduce the moment; however the change of pile spacing affects the moment more significantly.
Analysis of pile foundation size earthquake%桩基础尺寸抗震分析
Institute of Scientific and Technical Information of China (English)
张顺艳
2014-01-01
Pile soil structure interaction system based on,to establish the finite element model,calculation and analysis of influence of size on the depth of the pile length,pile using random response.Come to conclusion:Under the earthquake load,the pile length increased with the increasing of the whole frame structure seismic performance improvement in the overall trend,but the foundation is too long to bedrock seismic performance and reduced.The increase of pile diameter is beneficial to improve the seismic behavior of frame and pile,but continued to increase the effect of pile diameter is not obvious.%基于桩-土-结构共同作用体系，建立有限元模型，采用随机反应分析计算桩长、桩径对震陷深度的影响。得出结论：在地震荷载作用下，桩长的增加在整体趋势上有利于框架结构整体抗震性能的提高，但桩基太长到达基岩上抗震性能又有所降低。桩径的增大对提高框架和桩的抗震能力是有利的，但持续增大桩径的效果并不明显。
Analytical method of load-transfer of single pile under expansive soil swelling
Institute of Scientific and Technical Information of China (English)
FAN Zhen-hui; WANG Yong-he; XIAO Hong-bin; ZHANG Chun-shun
2007-01-01
The elastic differential equations of load-transfer of single pile either with applied loads on pile-top or only under the soil swelling were established, respectively, based on the theory of pile-soil interaction and the shear-deformation method. The derivation of analytic solution to load-transfer for single pile in expansive soil could hereby be obtained by means of superposition principle under expansive soils swelling. The comparison of two engineering examples was made to prove the credibility of the suggested method. The analyzed results show that this analytic solution can achieve high precision with few parameters required, indicating its' simplicity and practicability in engineering application. The employed method can contribute to determining the greatest tension along pile shaft resulting from expansive soils swelling and provide reliable bases for engineering design. The method can be employed to obtain various distributive curves of axial force, settlements and skin friction along the pile shaft with the changes of active depth, vertical movements of the surface and loads of pile-top.
Analytical investigation of pile-soil interaction in sand under axial and lateral loads
Abdel-Mohti, Ahmed; Khodair, Yasser
2014-03-01
This paper presents a numerical study of pile-soil interaction due to application of axial and lateral loads to piles in sand. The pile-soil interaction was analyzed using the finite difference (FD) software LPILE and two finite element (FE) software. The three-dimensional (3D) FE models of pile-soil interaction have been created using Abaqus/Cae and SAP2000. Various types of soft soil were studied, such as loose, medium, and dense sand. A lateral displacement of 2 cm was applied to the top of the pile while maintaining a zero slope in a guided fixation. A combined lateral and axial load of 300 kN was also studied. The paper compared between the bending moments and lateral displacements along the depth of the pile obtained from the FD solutions and FE analyses. A parametric study was conducted to study the effect of crucial design parameters such as the modulus of elasticity of soil and the number of nonlinear soil springs that can be used to model the soil. A good agreement between the results obtained by the FE models and the FD solution was observed. Also, the FE models were capable of predicting the pile-soil interaction for all types of soft soil.
Postmortem analysis of sand grain crushing from pile interface using X-ray tomography
Energy Technology Data Exchange (ETDEWEB)
Silva, I. Matias; Combe, Gaeel; Foray, Pierre; Flin, Frederic; Lesaffre, Bernard [Universite de Grenoble, 3SR Lab, UMR 5521 Grenoble-INP, UJF-Grenoble 1, CNRS, Grenoble, France CEN, CNRM-GAME UMR 3589, Meteo France - CNRS, Grenoble (France)
2013-06-18
Pile foundations of offshore platforms, wind and water turbines are typically subjected to a variety of cyclic loading paths due to their complex environment. While many studies focus on global pile behaviour, the soil-pile interface is explored here by a micromechanical study of the soil layer in contact with the pile surface. This work is devoted to the analysis of frozen post-mortem silica sand samples recovered at the pile interface following installation and cyclic loading tests in a calibration chamber using x-ray tomography. An experimental procedure developed for three dimensional (3D) snow imaging was adapted for the recovery of the in-situ sand samples to preserve their structure during tomography scans. 3D images at a pixel size of 7 {mu}m were then obtained using a cryogenic cell. Results confirm the presence of a shear band at the pile surface as well as void ratios changes in the direction of the pile's radius.
76 FR 10627 - Assumption Buster Workshop: Trust Anchors Are Invulnerable
2011-02-25
...) Committee, an interagency working group that coordinates cyber security research activities in support of... confident that they are immune from the attacks.'' This assertion underlies significant cyber security research and development that is aimed at developing and implementing invulnerable trust anchors,...
Localization in Wireless Sensor Networks and Anchor Placement
Directory of Open Access Journals (Sweden)
Benjamin Tatham
2012-06-01
Full Text Available Applications of wireless sensor network (WSN often expect knowledge of the precise location of the nodes. Many different localization protocols have been proposed that allow nodes to derive their location rather than equipping them with dedicated localization hardware such as GPS receivers, which increases node costs. We provide a brief survey of the major approaches to software-based node localization in WSN. One class of localization protocols with good localization performance patches together relative-coordinate, local maps into a global-coordinate map. These protocols require some nodes that know their absolute coordinates, called anchor nodes. While many factors influence the node position errors, in this class of protocols, using Procrustes Analysis, the placement of the anchor nodes can significantly impact the error. Through simulation, using the Curvilinear Component Analysis (CCA-MAP protocol as a representative protocol in this category, we show the impact of anchor node placement and propose a set of guidelines to ensure the best possible outcome, while using the smallest number of anchor nodes possible.
When Does Scale Anchoring Work? A Case Study
Sinharay, Sandip; Haberman, Shelby J.; Lee, Yi-Hsuan
2011-01-01
Providing information to test takers and test score users about the abilities of test takers at different score levels has been a persistent problem in educational and psychological measurement. Scale anchoring, a technique which describes what students at different points on a score scale know and can do, is a tool to provide such information.…
The importance of anchor text for ad hoc search revisited
M. Koolen; J. Kamps
2010-01-01
It is generally believed that propagated anchor text is very important for effective Web search as offered by the commercial search engines. "Google Bombs" are a notable illustration of this. However, many years of TREC Web retrieval research failed to establish the effectiveness of link evidence fo
Ten Anchor Points for Teaching Principles of Marketing
Tomkovick, Chuck
2004-01-01
Effective marketing instructors commonly share a love for their students, an affinity for the subject matter, and a devotion to continuous quality improvement. The purpose of this article is to highlight 10 anchor points for teaching Principles of Marketing, which are designed to better engage students in the learning process. These anchor…
A+: Adjusted anchored neighborhood regression for fast super-resolution
Timofte, Radu; De Smet, Vincent; Van Gool, Luc
2015-01-01
Timofte R., De Smet V., Van Gool L., ''A+: Adjusted anchored neighborhood regression for fast super-resolution'', Lecture notes in computer science, vol. 9006, part IV, pp. 111-126, 2015 (12th Asian conference on computer vision - ACCV 2014, November 1-5, 2014, Singapore).
Analytical Model for Hook Anchor Pull-Out
DEFF Research Database (Denmark)
Brincker, Rune; Ulfkjær, J. P.; Adamsen, P.;
1995-01-01
A simple analytical model for the pull-out of a hook anchor is presented. The model is based on a simplified version of the fictitious crack model. It is assume that the fracture process is the pull-off of a cone shaped concrete part, simplifying the problem by assuming pure rigid body motions...
Analytical Model for Hook Anchor Pull-out
DEFF Research Database (Denmark)
Brincker, Rune; Ulfkjær, J. P.; Adamsen, P.;
A simple analytical model for the pull-out of a hook anchor is presented. The model is based on a simplified version of the fictitious crack model. It is assumed that the fracture process is the pull-off of a cone shaped concrete part, simplifying the problem by assuming pure rigid body motions...
Impact of Enhanced Anchored Instruction in Inclusive Math Classrooms
Bottge, Brian A.; Toland, Michael D.; Gassaway, Linda; Butler, Mark; Choo, Sam; Griffen, Ann Katherine; Ma, Xin
2015-01-01
The Common Core State Standards for Mathematics will place more pressure on special education and math teachers to raise the skill levels of all students, especially those with disabilities in math (MD). The purpose of this study was to assess the effects of enhanced anchored instruction (EAI) on students with and without MD in co-taught general…
Experience-based, body-anchored qualitative research interviewing
DEFF Research Database (Denmark)
Stelter, Reinhard
2010-01-01
-anchored interviewing, and second, by an interview guide that explores a research participant's personal experience with mindfulness meditation. An excerpt from an interview is discussed to illustrate the advantages of this interview form, namely its value as a methodological instrument for qualitative research in...
Fullerene-based Anchoring Groups for Molecular Electronics
DEFF Research Database (Denmark)
Martin, Christian A.; Ding, Dapeng; Sørensen, Jakob Kryger;
2008-01-01
We present results on a new fullerene-based anchoring group for molecular electronics. Using lithographic mechanically controllable break junctions in vacuum we have determined the conductance and stability of single-molecule junctions of 1,4-bis(fullero[c]pyrrolidin-1-yl)benzene. The compound can...
Laboratory testing of cyclic laterally loaded pile in cohesionless soil. [MONOPILES
Energy Technology Data Exchange (ETDEWEB)
Hansen, Mette; Kirk Wolf, T. [COWI, Kgs. Lyngby (Denmark); Lange Rasmussen, K. [Niras, Aalborg (Denmark); Ravn Roesen, H.; Ibsen, L.B. [Aalborg Univ.. Dept. of Civil Engineering, Aalborg (Denmark)
2013-06-15
Offshore wind turbines are placed in a rough environment, subjected to variable lateral loads, mostly from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the soil-pile system which is critical in the serviceability limit state. The accumulated rotation due to long-term lateral loading is therefore a current issue of interest as today's design guidances have little knowledge in this area. The cost of large-scale testing is extensive which make small-scale testing desirable as a tool for describing the behaviour of a soil-pile system subjected to lateral load. In this paper small-scale testing of a pile subjected to cyclic, lateral loading is treated in order to investigate the effect of cyclic loading. The test pile has a diameter of 100 mm and is 600 mm high, making the slenderness ratio 6, which resembles the ratio of offshore wind turbines today. The test pile is placed in saturated dense sand. A monotonic test is conducted to define the ultimate lateral capacity. Afterwards a cyclic test is conducted to investigate the accumulation of rotation when the pile is subjected to cyclic lateral load. Force and displacement during both tests are recorded to determine the deformation of the pile. Comparing the responses of the monotonic and the cyclic test, the cyclic test shows a stiffer response. During the cyclic test, the rotation of the pile accumulates with decreasing rotation increments. However, no stabilised situation occurs. The measured data is compared to theories on degradation, agreeing that the accumulated rotation as an estimate can be express by both a logarithmic and exponential expression. Comparing the results from the cyclic test with results from other recent small-scale tests shows agreement in the accumulation of rotation with decreasing rotation increments with no stabilising situation. (Author)
Development of p-y Curves of Laterally Loaded Piles in Cohesionless Soil
Directory of Open Access Journals (Sweden)
Mahdy Khari
2014-01-01
Full Text Available The research on damages of structures that are supported by deep foundations has been quite intensive in the past decade. Kinematic interaction in soil-pile interaction is evaluated based on the p-y curve approach. Existing p-y curves have considered the effects of relative density on soil-pile interaction in sandy soil. The roughness influence of the surface wall pile on p-y curves has not been emphasized sufficiently. The presented study was performed to develop a series of p-y curves for single piles through comprehensive experimental investigations. Modification factors were studied, namely, the effects of relative density and roughness of the wall surface of pile. The model tests were subjected to lateral load in Johor Bahru sand. The new p-y curves were evaluated based on the experimental data and were compared to the existing p-y curves. The soil-pile reaction for various relative density (from 30% to 75% was increased in the range of 40–95% for a smooth pile at a small displacement and 90% at a large displacement. For rough pile, the ratio of dense to loose relative density soil-pile reaction was from 2.0 to 3.0 at a small to large displacement. Direct comparison of the developed p-y curve shows significant differences in the magnitude and shapes with the existing load-transfer curves. Good comparison with the experimental and design studies demonstrates the multidisciplinary applications of the present method.
A Single-hole stone anchor from Kottapatnam: Early historic port site of Andhra Pradesh, India
Digital Repository Service at National Institute of Oceanography (India)
Tripati, S.; Rao, K.P.; Kumari, S.; Imsong, O.; Vanlalhruaitluangi, V.
broken piece of polished stone celt in addition to other findings. The recent explorations brought to light a Vijayanagar period coin, pottery and a single hole stone anchor. The finding of the stone anchor throws light on the maritime activities...
Anchoring a Leviathan: How the Nuclear Membrane Tethers the Genome
Directory of Open Access Journals (Sweden)
Rafal eCzapiewski
2016-05-01
Full Text Available It is well established that the nuclear envelope has many distinct direct connections to chromatin that contribute to genome organization. The functional consequences of genome organization on gene regulation are less clear. Even less understood is how interactions of lamins and nuclear envelope transmembrane proteins (NETs with chromatin can produce anchoring tethers that can withstand the physical forces of and on the genome. Chromosomes are the largest molecules in the cell, making megadalton protein structures like the nuclear pore complexes and ribosomes seem small by comparison. Thus to withstand strong forces from chromosome dynamics an anchoring tether is likely to be much more complex than a single protein-protein or protein-DNA interaction. Here we will briefly review known NE-genome interactions that likely contribute to spatial genome organization, postulate in the context of experimental data how these anchoring tethers contribute to gene regulation, and posit several hypotheses for the physical nature of these tethers that need to be investigated experimentally. Significantly, disruption of these anchoring tethers and the subsequent consequences for gene regulation could explain how mutations in nuclear envelope proteins cause diseases ranging from muscular dystrophy to lipodystrophy to premature ageing progeroid syndromes. The two favored hypotheses for nuclear envelope protein involvement in disease are 1 weakening nuclear and cellular mechanical stability, and 2 disrupting genome organization and gene regulation. Considerable experimental support has been obtained for both. The integration of both mechanical and gene expression defects in the disruption of anchoring tethers could provide a unifying hypothesis consistent with both.
Characterizing the flow of stirred vessels with anchor type impellers
Directory of Open Access Journals (Sweden)
Peixoto S.M.C.
2000-01-01
Full Text Available Despite its importance in chemical industries, there are few works which studies anchor type impellers and only a fraction of the works investigate these systems under a computational approach. The great majority refers to turbine impellers, specially Rushton turbines, under turbulent flow. Anchor impellers are used specially for highly viscous flow, typical of polymer reactions. The viscosity is normally in the range 1000-10000 cp. Since this range of viscosity describe highly viscous flows, the reactions for anchor agitated systems are normally carried out under laminar flow. This work presents a detailed computational fluid dynamics (CFD approach to study the behaviour of stirred vessels using anchor impellers. The axial plane of the tank, which is being modelled, is divided into small control volumes, which collectively is referred to as the mesh, or grid. In each of these cells the momentum balance, energy and mass conservation, which describes the model, are rewritten algebraically using the finite volumes method to relate such variables as velocity, pressure and temperature to values in neighbouring cells. The equations are then solved numerically, and the results yield the flow corresponding to the model. Since the geometry of a vessel with anchor impellers strictly calls for a three dimensional method, an approximation is made to account for the effect of the blades (Kuncewics, 1992. The main objective of this work is to give a detailed description of the flow generated by this axial impeller with a view to indicate ways in which the design and operation of these systems can be improved.
Methods of pulse pile-up identification in digital nuclear spectrometer system
International Nuclear Information System (INIS)
The pulse amplitude's extraction and energy resolution can be affected by the pulse pile-up in digital nuclear spectrometer system. In order to reduce the effect, this article introduces a time comparison identification method to identify the situation of pulse pile-up, which will reduce the digital signal processing time and the effects of energy resolution. The impact of the count rate can be corrected by a simple correction method. Finally, the actual pile-up pulse and count rate have been processed by this method, the results of this method have been verified in practical applications. (authors)
Treating jet correlations in high pile-up at hadron colliders
Directory of Open Access Journals (Sweden)
F. Hautmann
2016-03-01
Full Text Available Experiments in the high-luminosity runs at the Large Hadron Collider face the challenges of very large pile-up. Primary techniques to deal with this are based on precise vertex and track reconstruction. Outside tracker acceptances, however, lie regions of interest for many aspects of the LHC physics program. We explore complementary approaches to pile-up treatment and propose a data-driven jet-mixing method which can be used outside tracker acceptances without depending on Monte Carlo generators. The method can be applied to treat correlation observables and take into account, besides the jet transverse momentum pedestal, effects of hard jets from pile-up.
An in-pile testing program to study the performance characteristics of coated particle fuels
International Nuclear Information System (INIS)
Sandia National Laboratories is actively involved in testing coated particle nuclear fuels for the Space Nuclear Thermal Propulsion (SNTP) program managed by Phillips Laboratory. The testing program integrates the results of numerous in-pile and out-of-pile tests with modeling efforts to qualify fuel and fuel elements for the SNTP program. This paper briefly describes the capabilities of the Annular Core Research Reactor (in which the experiments are performed), the major in-pile tests, and the models used to determine the performance characteristics of the fuel and fuel elements
Numerical Modelling of Large-Diameter Steel Piles at Horns Rev
DEFF Research Database (Denmark)
Augustesen, Anders Hust; Brødbæk, K. T.; Møller, M.;
2009-01-01
Today large-diameter monopiles are the most common foundation type used for large offshore wind farms. This paper aims to investigate the behaviour of monopiles under monotonic loading taking the interaction between the pile and the subsoil into account. Focus is paid to a monopile used as...... foundation for a wind turbine at Horns Rev located in the Danish sector of the North Sea. The outer diameter of the pile is 4 m and the subsoil at the location consists primarily of sand. The behaviour of the pile is investigated under realistic loading conditions by means of a traditional Winkler...
Elbetti, C; Giani, I; Novelli, E; Fucini, C; Martellucci, Jacopo
2015-12-01
The purpose of the paper is to compare Goligher Classification with the Single Pile Hemorrhoid Classification (SPHC) to show the possible bias and limits of Goligher's use and the possible advantage with the employment of the new classification. SPHC considers the number of pathological piles(N), the characteristics of each internal pile and the characteristics of each external pile, reporting the presence of a fibrous inelastic redundant pile(F), the presence of the subversion of dentate line or the congestion of the external pile(E) and the presence of not tolerated skin tags(S). From September 2010 to December 2012, 197 consecutive patients were analysed according to both classifications. Considering pathological piles, I and II Goligher patients showed a complete agreement between pathological pile and grade, III Goligher patients had 80.5 % of pathological piles of III grade while IV Goligher patients had only 44.3 % of IV grade pathological piles (p < 0.001). Regarding the distribution of the other anatomical variables: F, E, S described in SPHC, the results showed that F was present in 18.3 % while ES was present in 46.2 %. Goligher's Classification has showed to be an inadequate tool to overview surgical outcome or to compare surgical procedure, particularly for high grades, while SPHC showed to be a feasible instrument both to describe and to compare patients affected by hemorrhoid disease. PMID:26547759
GEZEN, Tuba; Köroğlu, Özlem
2014-01-01
AbstractAlthough career anchors are used as a career tool in organizations, are examined in many limited researches. The purpose of this study is to determine the career anchors which affect the job and career decision of the tourism students. Therefore, Tourism and Hotel Management students who attend four-year programs/departments of Balikesir University have been conducted surveys. The Career Anchors Scale developed by Schein (1990) has been used to determine the career anchors of the tour...
Developments, expectations of wave energy converters and mooring anchors in the UK
Huang, Ming; Aggidis, G. A.
2008-02-01
The paper introduces the important developments of Wave Energy Converters (WECs) in the UK, and the generic anchor types for WECs and similar structures. Several WECs and their characteristics are introduced to explain the development direction. The anchors are discussed in relation to the behaviour and performance of WECs, and comparisons are made with similar aspects of the offshore industry. Typical and desirable features of anchors for WECs are summarized. Additionally, expectations and research suggestions for WECs and their anchor design are presented.
Cement grouting during installation of ground anchors in non-cohesive soils
Domes, Xenia A. L.
2015-01-01
Pressure grouting during installation of grouted ground anchors is known to increase anchor capacity in non-cohesive soils, but little information is available on correlations between applied grouting pressures, duration of grouting, ground conditions and increase of anchor pull-out capacity. The presented PhD study is concerned with processes taking place during installation of grouted ground anchors in non-cohesive soils, where filtration of the cement grout is assumed. It...
A group of 20 stone anchors from the waters of Dwarka, on the Gujarat Coast, India
Digital Repository Service at National Institute of Oceanography (India)
Gaur, A; Sundaresh; Tripati, S.; Gudigar, P.; Vora, K.H.; Bandodkar, S.N.
A large number of stone anchors were discovered in a water depth of 10-14 m off Dwarka during the 1998-99 season. The seabed near the anchors consists of a ledge with an average height of 1 m. Several anchors were found trapped between the rocks...
33 CFR 401.83 - Reporting position at anchor, wharf, etc.
2010-07-01
... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Reporting position at anchor, wharf, etc. 401.83 Section 401.83 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT... § 401.83 Reporting position at anchor, wharf, etc. A vessel anchoring in a designated anchorage area,...
Goldmann, Anja S.; Schoedel, Christine; Walther, Andreas; Yuan, Jiayin; Loos, Katja; Mueller, Axel H. E.; Müller, Axel H.E.
2010-01-01
The functionalization of magnetite (Fe3O4) nanoparticles with dopamine-derived clickable biomimetic anchors is reported. Herein, an alkyne-modified catechol-derivative is employed as the anchor, as i) the catechol-functional anchor groups possess irreversible covalent binding affinity to Fe3O4 nanop
Numerical study of pile-up in bulk metallic glass during spherical indentation
Institute of Scientific and Technical Information of China (English)
2008-01-01
Pile-up around indenter is usually observed during instrumented indentation tests on bulk metallic glass. Neglecting the pile-up effect may lead to errors in evaluating hardness,Young’s modulus,stress-strain response,etc. Finite element analysis was employed to implement numerical simulation of spherical indentation tests on bulk metallic glass. A new model was proposed to describe the pile-up effect. By using this new model,the contact radius and hardness of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass were obtained under several different indenter loads with pile-up,and the results agree well with the data generated by numerical simulation.
Numerical study of pile-up in bulk metallic glass during spherical indentation
Institute of Scientific and Technical Information of China (English)
Al Ke; DAI LanHong
2008-01-01
Pile-up around indenter is usually observed during instrumented indentation tests on bulk metallic glass. Neglecting the pile-up effect may lead to errors in evaluating hardness, Young's modulus, stress-strain response, etc. Finite element analysis was employed to implement numerical simulation of spherical indentation tests on bulk metallic glass. A new model was proposed to describe the pile-up effect. By using this new model, the contact radius and hardness of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass were obtained under several different indenter loads with pile-up, and the results agree well with the data generated by numerical simulation.
Os 200 anos da pilha elétrica The 200 years of the electric pile
Directory of Open Access Journals (Sweden)
Aécio Pereira Chagas
2000-06-01
Full Text Available In celebration of the 200th anniversary of the electric pile, invented by Alessandro Volta, a synopsis of his letter to The Royal Society (London and of his biography is presented.
Modelling temperature-dependent heat production over decades in High Arctic coal waste rock piles
DEFF Research Database (Denmark)
Hollesen, Jørgen; Elberling, Bo; Jansson, P.E.
2011-01-01
Subsurface heat production from oxidation of pyrite is an important process that may increase subsurface temperatures within coal waste rock piles and increase the release of acid mine drainage, AMD. Waste rock piles in the Arctic are especially vulnerable to changes in subsurface temperatures...... as the release of AMD normally is limited by permafrost. Here we show that temperatures within a 20 year old heat-producing waste rock pile in Svalbard (78°N) can be modelled by the one-dimensional heat and water flow model (CoupModel) with a new temperature-dependent heat-production module that includes both...... biological and chemical oxidation processes and heat source depletion over time. Inputs to the model are meteorological measurements, physical properties of the waste rock material and measured subsurface heat-production rates. Measured mean annual subsurface temperatures within the waste rock pile are up...
2010-08-12
... National Oceanic and Atmospheric Administration RIN 0648-XY07 Takes of Marine Mammals Incidental to Specified Activities; Piling and Structure Removal in Woodard Bay Natural Resources Conservation Area, Washington AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric...
A reliable method to determine friction capacity of piles driven into clays
Energy Technology Data Exchange (ETDEWEB)
Kolk, H.J.; Velde, E. van der
1996-12-31
High quality data on axial pile load tests in clay were selected from the public domain and put into a data base. Subsequently, statistical analyses of these data were performed to firstly assess the reliability of current offshore design criteria and, secondly, to develop a statistically more reliable design method. These analyses reveal that the ratio between average ultimate skin friction and undrained shear strength (=alpha) reduces with increasing degree of overconsolidation and increasing pile slenderness (=pile length over diameter ratio). Soil plasticity is shown to have a negligible influence on this correlation. A simple algorithm accounting for these parameters is obtained from statistical analyses. Predictions of pile capacity made using this new method are shown to be more accurate than those made using conventional current design criteria.
Screening of plane S waves by an array of rigid piles in poroelastic soil
Institute of Scientific and Technical Information of China (English)
Yuan-qiang CAI; Guang-ya DING; Chang-jie XU
2008-01-01
An array of rigid piles used as a screening barrier for plane shear (S) waves is investigated in a homogeneous unbounded space. The dynamic poroelastic theory of Biot is employed, under the assumption of an incompressible solid grain. Using Fourier-Bessel series, the problem of multiple scattering is solved by imposing continuity conditions and equilibrium conditions at the soil-pile interfaces with the translational addition theorem. A parametric analysis is conducted to investigate the influence of the permeability of poroelastie soil, separation between piles, number of piles and frequency of incident waves on screening effectiveness of the barrier, and the results are compared with those in an elastic soil medium. Computed results show that the intrinsic permeability of the soil medium displays an apparent effect on the screening of plane S waves.
RCP 劲性复合桩的应用%The application of RCP composite pile
Institute of Scientific and Technical Information of China (English)
宋阳
2016-01-01
介绍了 RCP 劲性复合桩的技术原理，结合工程案例，从定点放线、搅拌钻进、水泥浆制作、桩芯植入等方面，阐述了 RCP 劲性复合桩的施工工艺流程及要点，并介绍了该技术的优点，可为其他项目桩基工程提供参考。%This paper introduced the technology principle of RCP composite piles,combining with the engineering case,starting from aspects of fixed-point sampling,mixing drilling,cement slurry prefabrication and inside pile planting,describes the construction process and points of RCP composite pile,and introduces the advantages of the technology,can provide a reference for other projects pile works.
Experimental and Analytical Investigations of Piles and Abutments of Integral Bridges
Arsoy, Sami
2000-01-01
Bridges without expansion joints are called "integral bridges." Eliminating joints from bridges crates concerns for the piles and the abutments of integral bridges because the abutments and the piles are subjected to temperature-induced cyclic lateral loads. As temperatures change daily and seasonally, the lengths of integral bridges increase and decrease, pushing the abutment against the approach fill and pulling it away. As a result the bridge superstructure, the abutment, the approach f...
John Rex; Stephane Dubé; Phillip Krauskopf; Shannon Berch
2016-01-01
Roadside processing of wood biomass leaves chip piles of varying size depending upon whether they were created for temporary storage, spillage, or equipment maintenance. Wood chips left in these piles can generate leachate that contaminates streams when processing sites are connected to waterways. Leachate toxicity and chemistry were assessed for pure aspen (Populus tremuloides Michx.), lodgepole pine (Pinus contorta Dougl.), hybrid white spruce (Picea engelmannii x glauca Parry), and black s...
Design of Continuous Flight Auger Pile Foundation for a Multi-Storey Apartment Building
Yatskevich, Yulia
2010-01-01
The object of this work was studying, systemizing and describing continuous flight auger (CFA) pile foundation design for a residential complex and calculating the bearing capacity of a single СFA pile on the basis of Russian Building Code. This thesis was written on the request of the YIT Lentek JSK Design Department. The information for the theoretical part was gathered from Russian Building Codes, theoretical manuals, other common available materials (including the Internet), and proje...
Pile-Reinforcement Behavior of Cohesive Soil Slopes: Numerical Modeling and Centrifuge Testing
Liping Wang; Ga Zhang
2013-01-01
Centrifuge model tests were conducted on pile-reinforced and unreinforced cohesive soil slopes to investigate the fundamental behavior and reinforcement mechanism. A finite element analysis model was established and confirmed to be effective in capturing the primary behavior of pile-reinforced slopes by comparing its predictions with experimental results. Thus, a comprehensive understanding of the stress-deformation response was obtained by combining the numerical and physical simulations. Th...
Jamming transition in a two-dimensional open granular pile with rolling resistance
Magalhães, Caio F. M.; Atman, Allbens P. F.; Gaël Combe; José G. Moreira
2014-01-01
We present a molecular dynamics study of the jamming/unjamming transition in two-dimensional granular piles with open boundaries. The grains are modeled by viscoelastic forces, Coulomb friction and resistance to rolling. Two models for the rolling resistance interaction were assessed: one considers a constant rolling friction coefficient, and the other one a strain dependent coefficient. The piles are grown on a finite size substrate and subsequently discharged through an orifice opened at t...
Optimal Pile Arrangement for Minimizing Excess Pore Water Pressure Build-Up
DEFF Research Database (Denmark)
Barari, Amin; Saadati, Meysam; Ibsen, Lars Bo;
2013-01-01
constitutive model for sandy soil, strength and stiffness reduction, and pile-soil interaction. The Mohr-Coulomb constitutive model coupled with Byrne pore pressure build-up model have been employed in the analysis. Numerical analysis results show that pile groups have significant influence on the dynamic...... response of sandy soil as they reduce the amount of excess pore pressure development during seismic shaking and may even prevent liquefaction....
Noise reduction by the application of an air-bubble curtain in offshore pile driving
Tsouvalas, A.; Metrikine, A. V.
2016-06-01
Underwater noise pollution is a by-product of marine industrial operations. In particular, the noise generated when a foundation pile is driven into the soil with an impact hammer is considered to be harmful for the aquatic species. In an attempt to reduce the ecological footprint, several noise mitigation techniques have been investigated. Among the various solutions proposed, the air-bubble curtain is often applied due to its efficacy in noise reduction. In this paper, a model is proposed for the investigation of the sound reduction during marine piling when an air-bubble curtain is placed around the pile. The model consists of the pile, the surrounding water and soil media, and the air-bubble curtain which is positioned at a certain distance from the pile surface. The solution approach is semi-analytical and is based on the dynamic sub-structuring technique and the modal decomposition method. Two main results of the paper can be distinguished. First, a new model is proposed that can be used for predictions of the noise levels in a computationally efficient manner. Second, an analysis is presented of the principal mechanisms that are responsible for the noise reduction due to the application of the air-bubble curtain in marine piling. The understanding of these mechanisms turns to be crucial for the exploitation of the maximum efficiency of the system. It is shown that the principal mechanism of noise reduction depends strongly on the frequency content of the radiated sound and the characteristics of the bubbly medium. For piles of large diameter which radiate most of the acoustic energy at relatively low frequencies, the noise reduction is mainly attributed to the mismatch of the acoustic impedances between the seawater and the bubbly layer. On the contrary, for smaller piles and when the radiated acoustic energy is concentrated at frequencies close to, or higher than, the resonance frequency of the air bubbles, the sound absorption within the bubbly layer
Policies for the Reduction of Slash Pile Burning in BC Forests
Kamp, Adam Roger
2013-01-01
In British Columbia, it is a common practice for forest companies to pile the unwanted fibre after harvest and burn the piles. There are numerous reasons why companies do this, but the primary reason is to reduce the forest fire risk. However, slash burning produces greenhouse gas emissions and local air contaminants. BC has also seen a significant reduction in the timber supply in interior regions due to the mountain pine beetle devastation. Thus, government and the industry are looking ...
Thermal safety analysis of aluminum matrix B4C irradiation in-pile
International Nuclear Information System (INIS)
Aluminum matrix B4C is a new structural material for spent fuel storage and related performances need in-depth research, especially the irradiation-resistance capability. The thermal calculations were completed by using the CFD software to ensure the safety of the in-pile irradiation test. Considering the characteristic of the irradiation project, the thermal safety feature of the in-pile test was analyzed, and the irradiation project was optimized. (authors)
Dynamic soil-pile-interaction effects on eigenfrequency and damping of slender structures
Zania, Varvara
2014-01-01
Single pile foundations have been widely used as a support solution for offshore wind turbines (OWT), where the design has been driven towards large diameter monopiles in order to satisfy the deformation limitations in the superstructure. The aim of the current study is to illustrate the effect of the dynamic soil-pile-interaction on the natural vibration characteristics of the flexibly supported structure. For this purpose a two-step iterative procedure has been developed based on two analyt...
A Simplified Method for Analysis of Geosynthetic Reinforcement Used in Pile Supported Embankments
Kang Fei
2014-01-01
The inclusion of geosynthetic reinforcement in the piled embankment can help transfer loads to the piles and reduce total and differential settlements. In order to select the appropriate reinforcement material, the reasonable calculation of the deflection and tension is very important. Current design methods usually do not represent the true three-dimensional (3D) nature of the displacements, strains, and stresses of the geosynthetics, and the resulting error may be large and cannot be neglec...
Anomalous Scaling Behaviors in a Rice-Pile Model with Two Different Driving Mechanisms
Institute of Scientific and Technical Information of China (English)
ZHANGDuan-Ming; SUNHong-Zhang; LIZhi-Hua; PANGui-Jun; YUBo-Ming; LIRui; YINYan-Ping
2005-01-01
The moment analysis is applied to perform large scale simulations of the rice-pile model. We find that this model shows different scaling behavior depending on the driving mechanism used. With the noisy driving, the rice-pile model violates the finite-size scaling hypothesis, whereas, with fixed driving, it shows well defined avalanche exponents and displays good finite size scaling behavior for the avalanche size and time duration distributions.
Wang, W. C.; Lin, D. G.
2015-12-01
This study investigates the bearing capacities and mechanical behaviors of pile foundation installed on the seabed of wind farm near Chang-Hua coast of western Taiwan for the supporting structure of offshore wind turbine. A series of three-dimensional (3-D) numerical modeling of pile foundation subjected to various types of combined loading were carried out using Plaix-3D finite element program to investigate the interactive behaviors between soil and pile. In the numerical modeling, pile diameter, pile length and pile spacing were selected as design parameters to inspect their effects on the bearing capacities and deformation behaviors of the pile foundation. For a specific design parameter combination, one can obtain the corresponding loading-displacement curve, various ultimate bearing capacities, V-H (Vertical-Horizontal combined loading) ultimate bearing capacity envelope, and p-ycurve of pile foundation. Numerical results indicate that: (1) Large displacement and plastic points at ultimate state mostly distribute and concentrate in the topsoil of seabed and around pile head. (2) The soil resistance on the soil-pile interface is ascending with the increases of depth, pile diameter and pile length. (3) The vertical and horizontal bearing capacities of pile group increase significantly with the increase of pile diameter. (4) The vertical and bending moment capacities of pile group increase greatly with the increase of pile length whereas the horizontal capacity is almost insensitive to pile length. (5) The bending moment of pile is highly influenced by the pile spacing. (6) For different design parameters, the shape of ultimate bearing capacity envelopes of pile group on V-H plane is similar while the envelopes will expand as the design parameters increase. For different loading levels of bending moment, the envelopes on V-H plane will contract gradually as the bending moment loading increasing.
Iron anchors of Northern Odisha, east coast India: Maritime contacts with European countries
Digital Repository Service at National Institute of Oceanography (India)
Tripati, S.; Patnaik, S.K.; Acharya, S.B.
at Siraf. Second Interim Report. Iran 8: 1–17. 12 List of Figures Figure 1. Iron anchor find sites, ports and trade centres of Odisha. Figure 2. Iron anchor found at Balaramgadi, Northern Odisha (Photo: Sila Tripati) Figure 2a. Iron anchor found... at Balaramgadi, Northern Odisha (S.B. Chitari & Rudra Behera). Figure 3. Iron anchor found at Chandabali on the mouth of the River Baitarani (OMISEAS, Bhubaneswar). Figure 4. Iron anchor found at Chandabali on the mouth of the River Baitarani (Photo: Sila...
Torsional dynamic analysis of single piles by time-domain BEM
Tham, L. G.; Cheung, Y. K.; Lei, Z. X.
1994-07-01
The transient dynamic response of single piles in a layered half-space under a time-dependent torque is analyzed by a coupled FEM-BEM approach in which the pile is modelled by FEM and the half-space by a general cylindrical co-ordinates time-domain BEM. By virtue of the Fourier theory, only one-dimensional discretization is necessary for the boundaries of the three-dimensional layered half-space, while the pile shaft can be discretized as a one-dimensional elastic column member. The compatibility and equilibrium conditions between pile shaft and soil layers are employed to assemble the respective equations into one set. A comparison is carried out to demonstrate the accuracy of the approach. The influence of several parameters on the transient behavior of single piles is investigated through numerical examples. Of all the parameters, the shear modulus ratio G(sub p)G(sub s) is found to be the most important governing factor. The other effective factors are the pile slenderness ratio l/r(sub 0), the soil layering and so on.
Institute of Scientific and Technical Information of China (English)
Hart Yingcai
2008-01-01
An investigation of soil-pile-structure interaction is carried out, based on a large reciprocating compressor installed on an elevated concrete foundation (table top structure). A practical method is described for the dynamic analysis, and compared with a 3D finite element (FE) model. Two commercial software packages are used for dynamic analysis considering the soil-pile-structure interaction (SPSI). Stiffness and damping of the pile foundation are generated fi-om a computer program, and then input into the FE model. To examine the SPSI thoroughly, three cases for the soil, piles and superstructure are considered and compared. In the first case, the interaction is fully taken into account, that is, both the superstructure and soil-pile system are flexible. In the second case, the superstructure is flexible but fixed to a rigid base, with no deformation in the base (no SSI). In the third case, the dynamic soil-pile interaction is taken into account, but the table top structure is assumed to be rigid. From the comparison beteen the results of these three cases some conclusions are made, which could be helpful for engineering practice.
Postmortem analysis of sand grain crushing from pile interface using X-ray tomography
International Nuclear Information System (INIS)
Pile foundations of offshore platforms, wind and water turbines are typically subjected to a variety of cyclic loading paths due to their complex environment. While many studies focus on global pile behaviour, the soil-pile interface is explored here by a micromechanical study of the soil layer in contact with the pile surface. This work is devoted to the analysis of frozen post-mortem silica sand samples recovered at the pile interface following installation and cyclic loading tests in a calibration chamber using x-ray tomography. An experimental procedure developed for three dimensional (3D) snow imaging was adapted for the recovery of the in-situ sand samples to preserve their structure during tomography scans. 3D images at a pixel size of 7 μm were then obtained using a cryogenic cell. Results confirm the presence of a shear band at the pile surface as well as void ratios changes in the direction of the pile’s radius.
Vertical Dynamic Response of Pile Embedded in Layered Transversely Isotropic Soil
Directory of Open Access Journals (Sweden)
Wenbing Wu
2014-01-01
Full Text Available The dynamic response of pile embedded in layered transversely isotropic soil and subjected to arbitrary vertical harmonic force is investigated. Based on the viscoelastic constitutive relations for a transversely isotropic medium, the dynamic governing equation of the transversely isotropic soil is obtained in cylindrical coordinates. By introducing the fictitious soil pile model and the distributed Voigt model, the governing equations of soil-pile system are also derived. Firstly, the vertical response of the soil layer is solved by using the Laplace transform technique and the separation of variables technique. Secondly, the analytical solution of velocity response in the frequency domain and its corresponding semianalytical solution of velocity response in the time domain are derived by means of inverse Fourier transform and convolution theorem. Finally, based on the obtained solutions, a parametric study has been conducted to investigate the influence of the soil anisotropy on the vertical dynamic response of pile. It can be seen that the influence of the shear modulus of soil in the vertical plane on the dynamic response of pile is more notable than the influence of the shear modulus of soil in the horizontal plane on the dynamic response of pile.
Integration of Small-Diameter Wood Harvesting in Early Thinnings using the Two pile Cutting Method
Energy Technology Data Exchange (ETDEWEB)
Kaerhae, Kalle (Metsaeteho Oy, P.O. Box 101, FI-00171 Helsinki (Finland))
2008-10-15
Metsaeteho Oy studied the integrated harvesting of industrial roundwood (pulpwood) and energy wood based on a two-pile cutting method, i.e. pulpwood and energy wood fractions are stacked into two separate piles when cutting a first-thinning stand. The productivity and cost levels of the integrated, two-pile cutting method were determined, and the harvesting costs of the two-pile method were compared with those of conventional separate wood harvesting methods. In the time study, when the size of removal was 50 dm3, the productivity in conventional whole-tree cutting was 6% higher than in integrated cutting. With a stem size of 100 dm3, the productivity in whole-tree cutting was 7% higher than in integrated cutting. The results indicated, however, that integrated harvesting based on the two-pile method enables harvesting costs to be decreased to below the current cost level of separate pulpwood harvesting in first thinning stands. The greatest cost-saving potential lies in small-sized first thinnings. The results showed that, when integrated wood harvesting based on the two-pile method is applied, the removals of both energy wood and pulpwood should be more than 15-20 m3/ha at the harvesting sites in order to achieve economically viable integrated procurement
Overview of release phenomenology in Phebus FP and comparison with out-of-pile experiments
International Nuclear Information System (INIS)
An estimate of the fission-product (FP) releases from fuel under reactor accident conditions is a key input to a source-term calculation. Numerous out-of-pile FP release experimental programs have been conducted over the years, including HEVA/VERCORS (France), HI/VI (U.S.A), VEGA (Japan) and HCE/UCE/MCE (Canada). These out-of-pile experiments have led to a good understanding of the fundamental phenomena affecting FP releases under accident conditions. One of the main objectives of the Phebus FP in-pile experimental program is to measure FP releases from fuel under conditions representative of Light Water Reactor (LWR) severe accident sequences. This paper presents a summary of the out-of-pile experiments and the fundamental phenomena affecting FP release from fuel under accident conditions. Releases determined in the Phebus FP in-pile tests conducted to date agree well with the results of out-of-pile tests for most volatile fission products. The extent of cladding oxidation makes a difference, particularly to the release kinetics. Releases for certain less-volatile fission-product elements, such as Mo and Ba, also show qualitative agreement for most tests. (author)
Long-term settlement prediction of high-speed railway bridge pile foundation
Institute of Scientific and Technical Information of China (English)
杨奇; 冷伍明; 张升; 聂如松; 魏丽敏; 赵春彦; 刘维正
2014-01-01
The process and characteristics of loading on high-speed railway bridge pile foundation were firstly obtained by means of field research and analysis, and the corresponding loading function was presented. One-dimensional consolidation equation of elastic multilayered soils was then established with single drainage or double drainages under multilevel loading. Moreover, the formulas for calculating effective stress and settlement were derived from the Laplace numerical inversion transform. The three-dimensional composite analysis method of bridge pile group was improved, where the actual load conditions of pile foundation could be simulated, and the consolidation characteristics of soil layers beneath pile were also taken into account. Eventually, a corresponding program named LTPGS was developed to improve the calculation efficiency. The comparison between long-term settlement obtained from the proposed method and the in-situ measurements of pile foundation was illustrated, and a close agreement is obtained. The error between computed and measured results is less than 1 mm, and it gradually reduces with time. It is shown that the proposed method can effectively simulate the long-term settlement of pile foundation and program LTPGS can provide a reliable estimation.
Effects of riverbed scour on seismic performance of high-rise pile cap foundation
Han, Zhenfeng; Ye, Aijun; Fan, Lichu
2010-12-01
To explore the seismic performance of a high-rise pile cap foundation with riverbed scour, a finite element model for foundations is introduced in the OpenSees finite element framework. In the model, a fiber element is used to simulate the pile shaft, a nonlinear p-y element is used to simulate the soil-pile interaction, and the p-factor method is used to reflect the group effects. A global and local scour model is proposed, in which two parameters, the scour depth of the same row of piles and the difference in the scour depth of the upstream pile and the downstream pile, are included to study the influence of scour on the foundation. Several elasto-plastic static pushover analyses are performed on this finite element model. The analysis results indicate that the seismic capacity (or supply) of the foundation is in the worst condition when the predicted deepest global scout depth is reached, and the capacity becomes larger when the local scour depth is below the predicted deepest global scout depth. Therefore, to evaluate the seismic capacity of a foundation, only the predicted deepest global scout depth should be considered. The method used in this paper can be also applied to foundations with other soil types.
Installation technique of the in-pile plug assembly for the neutron guide system at HANARO
International Nuclear Information System (INIS)
The research reactor HANARO in Korea will be equipped with a neutron guide system, in order to transport cold neutrons from the cold neutron source to the neutron scattering instruments in the neutron guide hall near the reactor building. The neutron guide system of HANARO consists of the in-pile plug assembly, the primary shutter, and out-of-pile neutron guides with dedicated secondary shutters. Functions of the in-pile plug assembly are to shield the reactor environment from a nuclear radiation and to support the neutron guides and maintain them precisely oriented. It is most important for the constructing of the neutron guide system to install new in-pile plug assembly with neutron guides precisely at the beam port of the reactor in radiation environment. The installation tool was developed by KAERI, which enables the removal of old in-pile plug and the installation of the new in-pile plug assembly or the guide cassette under radiation shielding. This paper presents the installation technique of the inpile plug assembly using this newly developed tool
A method for the reinforcement of a longwall with a wedge pile
Energy Technology Data Exchange (ETDEWEB)
Levkovich, P.E.; Borisov, Iu.D.; Savich, N.S.
1981-01-01
The purpose of this investigation is to increase the productivity of reinforcement. In order to attain the given purpose, a second support pile is reinforced to the flexible pull on the other end of the longwall, and the supply of the support and its dismantling is carried out alternately by the holding support piles in respect to each in the corresponding half of the longwall, combining the shift of one of the support piles to the place of the support installation with the shift of the other to the prepared face. With this during the time of the dismantling of the support by the second support pile in the second half of the longwall in the prepared face, arranged on the opposite end of the longwall, the first support pile is disconnected from the flexible pulling device, and after the dismantling of the support system in the second half of the longwall, the flexible fulling unit is dragged in the direction of the prepared face which is adjacent to it at a pitch for the installation of the support, after which the first support pile is again connected to it.
Shake table test of soil-pile groups-bridge structure interaction in liquefiable ground
Tang, Liang; Ling, Xianzhang; Xu, Pengju; Gao, Xia; Wang, Dongsheng
2010-03-01
This paper describes a shake table test study on the seismic response of low-cap pile groups and a bridge structure in liquefiable ground. The soil profile, contained in a large-scale laminar shear box, consisted of a horizontally saturated sand layer overlaid with a silty clay layer, with the simulated low-cap pile groups embedded. The container was excited in three El Centro earthquake events of different levels. Test results indicate that excessive pore pressure (EPP) during slight shaking only slightly accumulated, and the accumulation mainly occurred during strong shaking. The EPP was gradually enhanced as the amplitude and duration of the input acceleration increased. The acceleration response of the sand was remarkably influenced by soil liquefaction. As soil liquefaction occurred, the peak sand displacement gradually lagged behind the input acceleration; meanwhile, the sand displacement exhibited an increasing effect on the bending moment of the pile, and acceleration responses of the pile and the sand layer gradually changed from decreasing to increasing in the vertical direction from the bottom to the top. A jump variation of the bending moment on the pile was observed near the soil interface in all three input earthquake events. It is thought that the shake table tests could provide the groundwork for further seismic performance studies of low-cap pile groups used in bridges located on liquefiable groun.
Influence of dynamic soil-pile raft-structure interaction: an experimental approach
Saha, Rajib; Haldar, Sumanta; Dutta, Sekhar Chandra
2015-12-01
Traditionally seismic design of structures supported on piled raft foundation is performed by considering fixed base conditions, while the pile head is also considered to be fixed for the design of the pile foundation. Major drawback of this assumption is that it cannot capture soil-foundation-structure interaction due to flexibility of soil or the inertial interaction involving heavy foundation masses. Previous studies on this subject addressed mainly the intricacy in modelling of dynamic soil structure interaction (DSSI) but not the implication of such interaction on the distribution of forces at various elements of the pile foundation and supported structure. A recent numerical study by the authors showed significant change in response at different elements of the piled raft supported structure when DSSI effects are considered. The present study is a limited attempt in this direction, and it examines such observations through shake table tests. The effect of DSSI is examined by comparing dynamic responses from fixed base scaled down model structures and the overall systems. This study indicates the possibility of significant underestimation in design forces for both the column and pile if designed under fixed base assumption. Such underestimation in the design forces may have serious implication in the design of a foundation or structural element.
Institute of Scientific and Technical Information of China (English)
曹兆虎; 刘汉龙; 孔纲强; 周航
2015-01-01
A small-scale physical modelling method was developed to investigate the pile bearing capacity and the soil displacement around the pile using transparent soil and particle image velocimetry(PIV) technique. Transparent sand was made of baked quartz and a pore fluid with a matching refractive index. The physical modelling system consists of a loading system, a laser light, a CCD camera, an optical platform and a computer for image analyzing. A distinctive laser speckle was generated by the interaction between the laser light and transparent soil. Two laser speckle images before and after deformation were used to calculate the soil displacement field using PIV. Two pipe piles with different diameters under oblique pullout loads at angles of 0°, 30°, 45°, 60° and 90° were used in tests. The load-displacement response, oblique pullout ultimate resistances and soil displacement fields were then studied. The test results show that the developed physical modelling method and transparent soil are suitable for pile-soil interaction problems. The soil displacements around the pipe piles will improve the understanding on the capacity of pipe piles under oblique pullout loads.
Han, Yingcai
2008-09-01
An investigation of soil-pile-structure interaction is carried out, based on a large reciprocating compressor installed on an elevated concrete foundation (table top structure). A practical method is described for the dynamic analysis, and compared with a 3D finite element (FE) model. Two commercial software packages are used for dynamic analysis considering the soil-pile-structure interaction (SPSI). Stiffness and damping of the pile foundation are generated from a computer program, and then input into the FE model. To examine the SPSI thoroughly, three cases for the soil, piles and superstructure are considered and compared. In the first case, the interaction is fully taken into account, that is, both the superstructure and soil-pile system are flexible. In the second case, the superstructure is flexible but fixed to a rigid base, with no deformation in the base (no SSI). In the third case, the dynamic soil-pile interaction is taken into account, but the table top structure is assumed to be rigid. From the comparison beteen the results of these three cases some conclusions are made, which could be helpful for engineering practice.
Bracing system of the reflecting sheets making up an insulating pile
International Nuclear Information System (INIS)
In order to reduce heat and radiation losses, the body of nuclear reactors and the connected pipe work are encased in reflecting and insulating piles of thin spaced sheets of aluminium or stainless steel. These spaced sheets are then encased in thicker and more solid internal and external shells. The piles and shells are generally shaped to follow the contour of the reactor and connected piping. It is therefore necessary to have available a study bracing system to keep the pile intact during the various handling and assembly operations. The fastening system must also exert an effect on the edge of the pile to prevent the sheets making it up from shifting in relation to each other. The description is given of a fastening system that includes an oblong section to be fitted along the edges of the piles up sheets; bracing substantially perpendicular to the oblong section, to space the sheets of the stack in pairs; and a maintaining system, normally perpendicular to the oblong section, to enable the fastener to be clipped to the edge of the sheets by bending it around the edge of each sheet of the pile
Static nonlinear analysis of piles cap based on the Continuum Damage Mechanics
Directory of Open Access Journals (Sweden)
Luiz Antonio Farani de Souza
2015-10-01
Full Text Available The piles cap is an important structural element whose function is to transfer the actions of the superstructure for a group of piles. The visual inspection of the piles cap behavior under service conditions is not possible and, in addition, the knowledge of its actual structural performance is a vital necessity for the constructions overall stability. In this paper, a two-dimensional nonlinear analysis is carried out, by means of Finite Element Method, of a reinforced concrete pile caps with two piles found in the literature. It adopts for the material concrete a constitutive model based on the Continuum Damage Mechanics, with the possibility to provide a tensile and compression differentiated behavior. The steel is described by an elastoplastic bilinear model. The equilibrium path is achieved by Arc Length iteration technique in association with the Newton - Raphson Method. The numerical results obtained with the developed computational code are compared with the available experimental and numerical results and the analytical solution, and have the objective of evaluate the potential of the proposed modeling as an investigation numerical tool to determine the rupture force and the damage distribution in the piles cap.
Precision physics with pile-up insensitive observables
Frye, Christopher; Schwartz, Matthew D; Yan, Kai
2016-01-01
To deepen the search for beyond the Standard Model physics, the Large Hadron Collider is pushing to higher and higher luminosity. At high luminosity, precision physics becomes increasingly difficult due to contamination from additional proton collisions per bunch crossing called pile-up. In recent years, many methods have been developed to cull this excess mostly low-energy radiation away from important signal regions, but it has been unclear if these methods were amenable to systematically-improvable theoretical understanding. In this paper, it is shown that one such method, soft drop jet grooming, has excellent theoretical properties: it is ultra-local, depending on only radiation within a jet, and it is free of non-global logarithms. Calculations of the soft drop jet mass and related observables are presented at next-to-next-to-leading logarithmic accuracy matched to next-to-next-to-leading fixed-order in perturbative Quantum Chromodynamics. Once measured at the Large Hadron Collider, precision comparisons...
Early corrosion monitoring of prestressed concrete piles using acoustic emission
Vélez, William; Matta, Fabio; Ziehl, Paul H.
2013-04-01
The depassivation and corrosion of bonded prestressing steel strands in concrete bridge members may lead to major damage or collapse before visual inspections uncover evident signs of damage, and well before the end of the design life. Recognizing corrosion in its early stage is desirable to plan and prioritize remediation strategies. The Acoustic Emission (AE) technique is a rational means to develop structural health monitoring and prognosis systems for the early detection and location of corrosion in concrete. Compelling features are the sensitivity to events related to micro- and macrodamage, non-intrusiveness, and suitability for remote and wireless applications. There is little understanding of the correlation between AE and the morphology and extent of early damage on the steel surface. In this paper, the evidence collected from prestressed concrete (PC) specimens that are exposed to salt water is discussed vis-à-vis AE data from continuous monitoring. The specimens consist of PC strips that are subjected to wet/dry salt water cycles, representing portions of bridge piles that are exposed to tidal action. Evidence collected from the specimens includes: (a) values of half-cell potential and linear polarization resistance to recognize active corrosion in its early stage; and (b) scanning electron microscopy micrographs of steel areas from two specimens that were decommissioned once the electrochemical measurements indicated a high probability of active corrosion. These results are used to evaluate the AE activity resulting from early corrosion.
Mobile Anchor Assisted Node Localization for Wireless Sensor Networks
Chen, Hongyang; Huang, Pei; Poor, H Vincent; Sezaki, Kaoru
2009-01-01
In this paper, a cooperative localization algorithm is proposed that considers the existence of obstacles in mobilityassisted wireless sensor networks (WSNs). In this scheme, a mobile anchor (MA) node cooperates with static sensor nodes and moves actively to refine location performance. The localization accuracy of the proposed algorithm can be improved further by changing the transmission range of mobile anchor node. The algorithm takes advantage of cooperation betweenMAs and static sensors while, at the same time, taking into account the relay node availability to make the best use of beacon signals. For achieving high localization accuracy and coverage, a novel convex position estimation algorithm is proposed, which can effectively solve the localization problem when infeasible points occur because of the effects of radio irregularity and obstacles. This method is the only range-free based convex method to solve the localization problem when the feasible set of localization inequalities is empty. Simulatio...