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Showing papers on "Lateral earth pressure published in 2005"



Journal ArticleDOI
TL;DR: In this article, the deformation characteristics of soil subjected to vacuum pressure are discussed and an approximate method is proposed for calculating settlement and lateral displacement of the ground induced by vacuum consolidation.
Abstract: The deformation characteristics of soil subjected to vacuum pressure are discussed and an approximate method is proposed for calculating settlement and lateral displacement of the ground induced by vacuum consolidation. Laboratory oedometer test results indicate that if the vacuum pressure alone is larger than the lateral stress required to maintain an at-rest (no horizontal strain) condition, there will be inward lateral displacement and the vacuum pressure will induce generally less settlement than a surcharge load of the same magnitude. In the case of field vacuum consolidation, the confining stress acting on a soil element can be regarded as consisting of two parts: Due to vacuum pressure and earth pressure. Assuming a value of the lateral earth pressure coefficient acting in the ground under vacuum consolidation ( kao ) , somewhere between the active and at-rest values, an equation defining the depth—below which there will be no significant inward lateral displacement—is derived. Further, assuming th...

175 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present an experimental study of the earthquake performance of modular-block reinforced soil retaining walls which were backfilled with sand using large-scale benchmark shaking table tests.
Abstract: This paper presents an experimental study of the earthquake performance of modular-block reinforced soil retaining walls which were backfilled with sand using large-scale benchmark shaking table tests. The reinforcements used were polymeric geogrids, which were frictionally connected to the facing blocks having a front lip. In addition to observing the seismic performance, the purpose of testing was to generate quality data for future validation of numerical procedures. Three large-scale 2.8 m high modular-block geosynthetic-reinforced soil walls were subjected to significant shaking using the Kobe earthquake motions. Each wall was excited with a one-dimensional horizontal maximum acceleration of 0.4g followed by 0.86g. Vertical acceleration was superimposed on the horizontal one in the third wall. The walls were instrumented intensively using over 100 transducers to measure lateral and vertical earth pressures, wall facing displacement, crest settlement, reinforcement strains, and accelerations within the soil and the facing blocks. The material properties, instrumentations, and construction procedures are described. The test results indicated that the walls deformed very little with negligible horizontal acceleration amplification when subjected to the first shaking load. Deformation and horizontal acceleration amplification were reasonably small under the second shaking load. Part of the lateral deflection, earth pressure and tensile force in the reinforcement were recovered when shaking ceased. Amplification ratio of 1.35 indicated that the particular wall system performed better than conventional walls that had been tested for earthquake loading.

165 citations


Book
25 Feb 2005
TL;DR: In this article, the authors present an investigation and an analysis of the impact of rainfall on the stability of the ground water and its properties in the presence of landslides and landslides.
Abstract: Relative Cost of Construction. Metric Conversions. About This Book. About the Author. Preface. Acknowledgments. PART A: INVESTIGATIONS AND ANALYSES. Chapter 1: Landslides. 1.1 Scope of the Book. 1.2 Landslide Descriptions. 1.3 Landslide Classification. 1.4 Prevention of Landslides. 1.5 Remediation of Landslides. Chapter 2: Landslide Occurrences. 2.1 Rainfall. 2.2 Springs and Seepage. 2.3 Irrigation and Aqueducts. 2.4 Weathering. 2.5 Fills. 2.6 Earth Dams and Reservoirs. 2.7 Cuts. 2.8 Artesian Pressures. 2.9 Concentrated Water Sources. 2.10 River Erosion. 2.11 Coastal Erosion. 2.12 Subaerial Submarine Flow Slides. 2.13 Debris Flow. 2.14 Ancient Landslide Reactivation. 2.15 Delayed Failure. 2.16 Earthquakes. 2.17 Rock Slopes. 2.18 Loess Slopes. 2.19 Highly Sensitive Silt and Clay. Chapter 3: Field Investigations. 3.1 Scope of Site Investigations. 3.2 Preliminary Site Investigation. 3.3 Geological Mapping. 3.4 Topography. 3.5 Survey Monitoring. 3.6 Difficult Access. 3.7 Overburden Drilling. 3.8 Standard Penetration Test. 3.9 Relatively Undisturbed Sampling. 3.10 Test Pits,Trenches, Shafts, and Adits. 3.11 Geophysical Explorations. 3.12 Field Vane Test. Chapter 4: Inclinometers and Piezometers. 4.1 Inclinometers. 4.2 Piezometers. 4.3 Automatic Data Acquisition Systems. Chapter 5: Groundwater. 5.1 Groundwater Profile. 5.2 Groundwater Flow along a Shear Zone. 5.3 Effect of Rainfall on Groundwater Levels. 5.4 Selection of Groundwater Levels in a Stability Analysis. 5.5 Measurements of Field Permeability. Chapter 6: Laboratory Shear Strength Measurements on Soils. 6.1 Basic Concepts. 6.2 Principle of Effective Stress. 6.3 Pore Pressure Parameters A and B. 6.4 Triaxial Tests. 6.5 Shear Box Test. 6.6 Ring Shear Test. 6.7 Plane Strain Test. 6.8 Mohr Diagram. 6.9 Liquefaction Test. 6.10 Additional Laboratory Shear Strength Tests. Chapter 7: Properties of Sands and Other Cohesionless Soils. 7.1 Classification. 7.2 Gradation and Engineering Properties. 7.3 Relative Density. 7.4 Angle of Repose. 7.5 Laboratory Drained Strength of Sand. 7.6 Drained Strength Estimates. 7.7 Selection of Drained Shear Strength of Sands for Stability Analysis. 7.8 Laboratory Undrained Strength of Sands. 7.9 Active, Passive, and At-Rest Earth Pressure Coefficients. 7.10 Field Behavior of Sands and Other Cohesionless Soils. Chapter 8: Properties of Clays and Cohesive Soils. 8.1 Description and Classification of Silts and Clays. 8.2 Silt and Clay Classification Using Cohesive Index. 8.3 Silt and Clay Consistency. 8.4 Rate of Consolidation. 8.5 Normally Consolidated and Overconsolidated Clays. 8.6 Laboratory Drained Strength of Clays and Silts. 8.7 Laboratory Undrained Strength of Clays and Silts. 8.8 Residual Strength of Clay. 8.9 Normally Consolidated Clay: Short-Term Stability. 8.10 Normally Consolidated Clay: Long-Term Stability. 8.11 Overconsolidated Clay: Short-Term Stability. 8.12 Overconsolidated Clay: Long-Term Stability. 8.13 Shear Movements and Failure in Overconsolidated Clay Slopes . Chapter 9: Slope Stability Analyses. 9.1 Measurement of Soil Density. 9.2 Total Stress and Effective Stress Analyses. 9.3 Landslide Shear Surfaces. 9.4 Back Analyses. 9.5 Vertical Cut in Clay. 9.6 Infinite Slope Analysis. 9.7 Double-Wedge Analysis. 9.8 Triple-Wedge Analysis. 9.9 Circular Arc Analysis. 9.10 Other Circular and Noncircular Stability Analyses. 9.11 Special Cases: (a) Partly Submerged Slope. 9.12 Special Cases: (b) Partly Consolidated Soils. 9.13 Special Cases: (c) Artesian Pressures. 9.14 Special Cases: (d) Pile Resistance. 9.15 Special Cases: (e) Rapid Drawdown Analysis. 9.16 Special Cases: (f) Three-Dimensional Analysis. 9.17 Special Cases: (g) Unsaturated Soils. 9.18 Stability Charts. 9.19 Neutral Line Concept. Chapter 10: Stability Margin. 10.1 Factor of Safety. 10.2 Original Profile Analysis. 10.3 Observational Method. 10.4 Reliability Analysis (Taylor Series Method). Chapter 11: Erosion Control. 11.1 Filter Design. 11.2 Riprap Design. 11.3 Fabrics. Chapter 12: Earthquake-Induced Landslides. 12.1 Liquefaction Analysis. 12.2 Pseudostatic Analysis. 12.3 Displacement of Marginally Stable Slopes. PART B: REMEDIAL AND PREVENTATIVE OPTIONS. Chapter 13: Common Issues in Remediation. 13.1 What Is Sufficient Remediation? 13.2 Groundwater Lowering. 13.3 Filter and Drainage Layers. 13.4 Hard, Crushed Rockfill Properties and Construction. 13.5 Temporary Excavations and Closely Sequenced Construction. 13.6 Conceptual Construction Contract Costs. Chapter 14: Alternatives to Full Remediation of a Landslide. 14.1 No Action. 14.2 Maintenance. 14.3 Observations. 14.4 Avoidance. 14.5 Selective Stabilization. 14.6 Marginal Stabilization. Chapter 15: Earthworks. 15.1 Earthworks Overview. 15.2 Slope Regrading. 15.3 External Buttress. 15.4 Infill Buttress. 15.5 Replacement Buttress. 15.6 Shear Key. 15.7 Earthwork Specifications for Compacted Fill. Chapter 16: Erosion Control Measures. 16.1 Filter Systems. 16.2 Reverse Filters. 16.3 Riprap Slope Armor. 16.4 Grouted Riprap. 16.5 Gabion Mattresses. 16.6 Shotcrete. 16.7 Chunam Plaster. 16.8 Bioremediation. 16.9 Concrete Block Systems. 16.10 Trenchfill Revetment. Chapter 17: Dewatering Systems. 17.1 Common Dewatering Issues. 17.2 Horizontal Drains. 17.3 Trench Drains. 17.4 French Drains. 17.5 Drainage Blanket. 17.6 Deep Wells. 17.7 Wellpoint and Ejector Systems. 17.8 Relief Wells. 17.9 Vertical Gravity Drains. 17.10 Tunnels and Drainage Adits. 17.11 Vertical Shaft with Drainage Array. 17.12 Control of Surface Water and Water-Carrying Pipes. 17.13 Dewatering through Consolidation. 17.14 Prefabricated Vertical Drains. Chapter 18: Seepage Barriers. 18.1 Slurry Trench Cutoff Walls. 18.2 Slope Liners. 18.3 Grout Curtains. 18.4 Soil Mix Walls. Chapter 19: Retaining Walls. 19.1 Retaining Walls Overview. 19.2 Ground Anchors (Tiebacks). 19.3 Anchor Block and Element Walls. 19.4 Tied-Back Soldier Pile Walls. 19.5 Concrete Shear Pile Walls. 19.6 Tied-Back Slurry Trench Concrete Walls. 19.7 Masonry and Concrete Gravity Walls. 19.8 Concrete Cantilever Walls. 19.9 Concrete Crib Walls. 19.10 Bin Walls. 19.11 Gabion Walls. Chapter 20: Earth Reinforcement Systems. 20.1 Soil Nailing. 20.2 Micropiles. 20.3 Mechanically Stabilized Earth Walls. Chapter 21: Liquefaction Mitigation Techniques. 21.1 Compaction Grouting. 21.2 Dynamic Compaction. 21.3 Vibro-Compaction. 21.4 Stone Columns (Vibro-Replacement). 21.5 Excavation and Replacement. 21.6 Deep Soil Mixing. Chapter 22: Slip Surface Strengthening. 22.1 Isolated Shear Piles (Dowel Piles). 22.2 Other Techniques. Chapter 23: Landslide Hazard. 23.1 Landslide Hazard Mapping. 23.2 Rockfall Hazard Rating System. PART C: SELECTED CASE HISTORIES. Case History 1: Washington Park Reservoirs Slide. Case History 2: Beaver Shoreline Erosion. Case History 3: Bonners Ferry Slide. Case History 4: Washington Park Station Slide. Case History 5: Pelton Park Slide. Case History 6: Pelton Upper Slide. Case History 7: Skagway Marine Slide. Case History 8: Faraday Slide. Case History 9: Goat Lick Slide. Case History 10: Hagg Lake, Slides 4 and 3. Case History 11: Hagg Lake, Slide 6 . Case History 12: Crown Point Highway Rock Slide. References. Credits. Case History Cross-References. Index.

155 citations


Journal ArticleDOI
TL;DR: In this paper, a fundamental study of the soil response of laterally loaded piles subjected to lateral loads in sand is conducted using the non-linear finite element approach, and the effect of pile stiffness and diameter on the p-y response is not significant.

152 citations


Journal ArticleDOI
TL;DR: In this article, the effects of the inclusion of short fiber in sandy silt (SM) soil on the performance of reinforced walls were examined using the finite element method and the vertical and horizontal earth pressure, displacement and settlement of the wall face were analyzed.

144 citations


Journal ArticleDOI
TL;DR: In this article, a simple method is proposed for calculating the ultimate lateral resistance (including frontal soil resistance and side shear resistance) to piles in cohesionless soils, and the calculated ultimate lateral resistances from the proposed method agrees well with that obtained from centrifugal tests of flexible model piles.
Abstract: Several methods are available for predicting the ultimate lateral resistance to piles in cohesionless soils. However, these methods often produce significantly different ultimate resistance values. This makes it difficult for practicing engineers to effectively select the appropriate method when designing laterally loaded piles in cohesionless soils. By analyzing the lateral soil resistance distribution along the width of the pile and based on the test results of model rigid piles in cohesionless soils collected from the published literature, a simple method is proposed for calculating the ultimate lateral resistance (including frontal soil resistance and side shear resistance) to piles in cohesionless soils. The calculated ultimate lateral resistance from the proposed method agrees well with that obtained from centrifugal tests of flexible model piles. Predicting the lateral load capacity of laboratory and field rigid test piles in cohesionless soils using the proposed method also yields satisfactory results.

143 citations


Journal ArticleDOI
TL;DR: In this article, numerical tools based on a discrete method (particulate materials) have been used to design both tunnels and tunneling machines, and the results from the models are compared with real data.
Abstract: Two extension projects have been carried out recently on the Madrid Metro, including 97 km of large-diameter (9.38 m) tunnels. Some technical specifications for the shields (thrust and torque) needed to excavate the tunnels have been analyzed in this work. The soil stability problem at the tunnel face has also been studied. Numerical tools based on a discrete method (particulate materials) have been used for these purposes. Results from the models are compared with real data and show the promising possibilities of the method to design both tunnels and tunneling machines.

123 citations


Journal ArticleDOI
TL;DR: In this paper, a finite-element method of solution was developed to investigate parametrically the effects of flexural wall rigidity and the rocking base compliance on rigid and flexible retaining walls against earthquakes.

115 citations


Journal ArticleDOI
TL;DR: In this paper, a suite of 2D and 3D finite element (FE) analyses of tunnel construction in London Clay is presented, and it is shown that even with a high degree of soil anisotropy, the transverse settlement trough remains too shallow.
Abstract: Finite element (FE) analysis is now often used in engineering practice to model tunnel-induced ground surface settlement. For initial stress regimes with a high coefficient of lateral earth pressure at rest, K0, it has been shown by several studies that the transverse settlement trough predicted by two-dimensional (2D) FE analysis is too wide when compared with field data. It has been suggested that 3D effects and/or soil anisotropy could account for this discrepancy. This paper presents a suite of both 2D and 3D FE analyses of tunnel construction in London Clay. Both isotropic and anisotropic non-linear elastic pre-yield models are employed, and it is shown that, even for a high degree of soil anisotropy, the transverse settlement trough remains too shallow. By comparing longitudinal settlement profiles obtained from 3D analyses with field data it is demonstrated that the longitudinal trough extends too far in the longitudinal direction, and that consequently it is difficult to establish steady-state set...

113 citations


Journal ArticleDOI
TL;DR: In this article, a two-dimensional frictionless wall is designed against sliding using Rankine's earth pressure theory, and the design friction angle and unit weight values are calculated using random field simulation.
Abstract: Retaining wall design has long been carried out with the aid of either the Rankine or Coulomb theories of earth pressure. To obtain a closed-form solution, these traditional earth pressure theories assume that the soil is uniform. The fact that soils are actually spatially variable leads, however, to two potential problems in design: do sampled soil properties adequately reflect the effective properties of the entire retained soil mass, and does spatial variability of soil properties lead to active earth pressure effects that are significantly different from those predicted using traditional models? This paper combines non-linear finite element analysis with random field simulation to investigate these two questions and assess just how safe current design practice is. The specific case investigated is a two-dimensional frictionless wall retaining a cohesionless drained backfill. The wall is designed against sliding using Rankine's earth pressure theory. The design friction angle and unit weight values are...

Journal ArticleDOI
TL;DR: In this article, the authors proposed a pseudostatic approach for estimating the seismic passive earth pressure coefficients by considering the effects of cohesion, surcharge, and own weight, and the minimum seismic passive force was obtained by adding individual minimum values of these components.
Abstract: Seismic passive earth pressure coefficients were computed by the method of limit equilibrium using a pseudostatic approach for seismic forces. Composite curved rupture surfaces were considered in the analysis. While earlier studies using this type of analysis were mainly for sands, seismic passive earth pressure coefficients were obtained in the present study considering the effects of cohesion, surcharge, and own weight. The minimum seismic passive force was obtained by adding the individual minimum values of these components and the validity of the principle of superposition was examined. Other parameters considered in the analysis were wall batter angle, ground surface slope, soil friction angle, wall friction angle, wall adhesion to soil cohesion ratio, and horizontal and vertical seismic accelerations. The seismic earth pressure coefficients were found to be highly sensitive to the seismic acceleration coefficients both in the horizontal and vertical directions. Results of the study are presented in the form of figures and tables. Comparisons of the proposed method with available theories in the seismic case are also presented.

Journal ArticleDOI
TL;DR: In this article, a validated finite element procedure was used for conducting a series of parametric studies on the behavior of reinforced soil walls under construction and subject to earthquake loading, and the performance of the wall was presented for the facing deformation and crest surface settlement, lateral earth pressure, tensile force in the reinforcement layers and acceleration amplification.
Abstract: The finite element procedures are extremely useful in gaining insights into the behavior of reinforced soil retaining walls. In this study, a validated finite element procedure was used for conducting a series of parametric studies on the behavior of reinforced soil walls under construction and subject to earthquake loading. The procedure utilized a nonlinear numerical algorithms that incorporated a generalized plasticity soil model and a bounding surface geosynthetic model. The reinforcement layouts, soil properties under monotonic and cyclic loadings, block interaction properties, and earthquake motions were among major variables of investigation. The performance of the wall was presented for the facing deformation and crest surface settlement, lateral earth pressure, tensile force in the reinforcement layers, and acceleration amplification. The effects of soil properties, earthquake motions, and reinforcement layouts are issues of major design concern under earthquake loading. The deformation, reinforcement force, and earth pressure increased drastically under earthquake loading compared to end of construction.

Journal ArticleDOI
TL;DR: In this paper, closed form equations for calculating the lateral displacement caused by the installation of soil-cement columns are derived based on cylindrical cavity expansion theory, mainly with reference to the amount of admixture injected and injection pressure as well as the stiffness of the surrounding soil.
Abstract: Closed form equations for calculating the lateral displacement caused by the installation of soil-cement columns are derived based on cylindrical cavity expansion theory. The radius of the cavity needs to be predetermined empirically, mainly with reference to the amount of admixture injected and injection pressure as well as the stiffness of the surrounding soil. Also, an empirical equation is proposed for considering the partial "plane strain" effect of installing a row of columns. The proposed method has been applied to four reported field tests conducted in Saga, Japan, using the slurry double mixing ~SDM! method, the dry jet mixing ~DJM! method, and the wet jet mixing ~WJM! method. The radius of influence, i.e., where the lateral displacement in the soil is less than 5 mm during the installation of soil-cement columns, is found from the field data to be approximately 30, 40, and 50 m for the SDM, DJM, and WJM, respectively. It is shown that the proposed method yielded a reasonable prediction of these field measurements. The field data also indicate that the installation sequence has a considerable influence on the observed lateral displacement; but the proposed method can only consider two extreme conditions of this influence. It is suggested that the method is a useful tool for the design of soft subsoil improvement resulting from the installation of soil-cement columns.

Journal ArticleDOI
TL;DR: In this paper, the null method is used to balance the output of a strain gage bridge bonded to the sensing element in an underflected state, and the result is that the membrane does not interact with the surrounding soil, and errors due to arching are eliminated.
Abstract: The paper presents the design, development, and calibration of a soil contact pressure transducer, based on the null method. Air pressure regulated in a tightly controlled PID loop balances the output of a strain gage bridge bonded to the sensing element. This action maintains the sensing element in an underflected state. The result is that the membrane does not interact with the surrounding soil, and errors due to arching are eliminated. In theory, the air pressure required to keep the sensing element in its undeflected state should be equal to the soil contact pressure applied at the soil boundary interface. Calibration of the sensor reveals that its response is exactly as anticipated. The ratio between the required null pressure and applied soil pressure at the boundary interface is 1:1 and independent of soil type, soil stiffness, and load history. The paper presents calibration of the sensor for two very different sands, each at two significantly different levels of relative density. The sensitivity of the sensor is a function of the control software. In its present version the sensor responds accurately to pressure imbalances of 0.3 kPa.

Journal ArticleDOI
Farhang Ostadan1
TL;DR: In this article, a simplified method was developed to predict lateral seismic soil pressure for building walls, focusing on the building walls rather than retaining walls and specifically considering the dynamic soil properties and frequency content of the design motion in its formulation.

Journal ArticleDOI
TL;DR: In this article, the FLAC-2D Code using an explicit finite difference method is used to analyse seepage failure of the sandy soil within a cofferdam subjected to an upward flow.

Journal ArticleDOI
M. El Sawwaf1, A. Nazer1
TL;DR: In this paper, the authors present the results of laboratory model tests on the influence of soil confinement on the behavior of a model footing resting on granular soil and conclude that the bearing load capacity of a circular footing can be appreciably increased by soil confinement.
Abstract: This paper presents the results of laboratory model tests on the influence of soil confinement on the behavior of a model footing resting on granular soil. Confining cylinders with different heights and diameters were used to confine the sand. The ultimate bearing load of a circular footing supported on a three-dimensional confined sand bed was studied. The studied parameters include the cell height, cell diameter, the depth to the top of the cell, and the embedded depth of footing. Initially, the response of a nonconfined case was determined and then compared with that of confined soil. The results were then analyzed to study the effect of each parameter. The results indicate that the bearing load capacity of circular footing can be appreciably increased by soil confinement. It was concluded that such reinforcement resists lateral displacement of soil underneath the footing leading to a significant improvement in the response of the footing. For small cell diameters, the cell–soil footing behaves as one ...

Journal ArticleDOI
TL;DR: In this article, a simple apparatus for laboratory calibration of diaphragm type earth pressure cells (EPCs) was designed and a new testing device was fabricated to permit the application of normal stress to the EPC using various types of soil and load configurations.
Abstract: The objective of this study was to design a simple apparatus for laboratory calibration of diaphragm type earth pressure cells (EPC). A new testing device was fabricated to permit the application of normal stress to the EPC using various types of soil and load configurations. With respect to fluid pressure, the response of the EPC can be different for the simplest earth pressure conditions because of an arching effect or nonuniform contact stress. For an EPC with a rigid outer rim, sensitivities computed from soil calibrations were lower than those determined from fluid calibrations by about 20 %.

Journal ArticleDOI
TL;DR: In this article, a new method based on minimization of the moment ratio is proposed to determine the location of the pivot point of the sheet pile wall, which is applicable to both cohesionless and cohesive backfills.
Abstract: Cantilever sheet pile walls are used routinely to retain medium heights of earth in geotechnical practice. Earth pressures developed on either side of the sheet pile wall ensure its moment and force equilibrium. Cantilever sheet pile walls suffer rotation about a pivot point close to the base and generate passive and active earth pressures. Earlier methods to determine the pivot point either use iterative procedures or rely on centrifuge data or finite element analyses. In this paper a new method based on minimization of the moment ratio is proposed to determine the location of the pivot point. This method is applicable to both cohesionless and cohesive backfills. Consideration of moment equilibrium is sufficient to determine the pivot point and force equilibrium is automatically satisfied. The location of the pivot point obtained by this approach compared satisfactorily with the centrifuge and laboratory test data. The shear strength demand computed for these tests could predict when sheet pile walls became unstable. Finally the shear strength demand was linked to the shear strains and hence to the wall deflections that compare satisfactorily with experimental wall deflections.

Journal ArticleDOI
TL;DR: A series of 2-D centrifuge modeling tests with an in-flight shaker were carried out in order to model both the deformation characteristics of backfill and the seismic responses of caisson-type walls embedded in soils with various permeabilities as mentioned in this paper.

Patent
25 May 2005
TL;DR: In this paper, a large shield driving simulation test platform is presented, which includes the components of drawbar, soil box, rear back, main top device, several bags set in the soil box and pore pressure sensors which are connected with monitoring system, hydraulic system, control system and sealing device, etc.
Abstract: The present invention relates to a large shield driving simulation test platform. Its simulation shield driving machine adopts phi 1800 mm. Said shield driving simulation test platform also includes the components of drawbar, soil box, rear back, main top device, several bags set in the soil box, soil pressure sensors and pore pressure sensors which are set in the soil box and connected with monitoring system, hydraulic system, control system and sealing device, etc.

Journal ArticleDOI
TL;DR: A semianalytical solution to axisymmetric consolidation of a transversely isotropic soil layer resting on a rough impervious base and subjected to a uniform circular pressure at the ground surface is presented in this article.
Abstract: A semianalytical solution to axisymmetric consolidation of a transversely isotropic soil layer resting on a rough impervious base and subjected to a uniform circular pressure at the ground surface is presented. The analysis uses Biot's fully coupled consolidation theory for a transversely isotropic soil. The general solutions for the governing consolidation equations are derived by applying the Hankel and Laplace transform techniques. These general solutions are then used to solve the corresponding boundary value problem for the consolidation of a transversely isotropic soil layer. Once solutions in the transformed domain have been found, the actual solutions in the physical domain for displacements and stress components of the solid matrix, pore-water pressure and fluid discharge can finally be obtained by direct numerical inversions of the integral transforms. The accuracy of the present numerical solutions is confirmed by comparison with an existing exact solution for an isotropic and saturated soil that is a special case of the more general problem addressed. Further, some numerical results are presented to show the influence of the nature of material anisotropy, the surface drainage condition, and the layer thickness on the consolidation settlement and the pore pressure dissipation.

Journal ArticleDOI
TL;DR: In this paper, a parametric finite element study has been carried out to demonstrate the importance of clay strength and depth of clay layer on the earth pressures, strut loads, and bending moments for a strutted sheet pile wall in soft, essentially normally consolidated clay.
Abstract: A parametric finite element study has been carried out to demonstrate the importance of clay strength and depth of clay layer on the earth pressures, strut loads, and bending moments for a strutted sheet pile wall in soft, essentially normally consolidated clay. The clay is modeled as nonlinear and anisotropic. The modeled excavation is 10 m deep. For a shear strength profile giving a close to failure condition the maximum bending moment is found to be 6 times larger than for a clay profile with 40% higher strength, and the maximum strut loads are up to twice as large. The maximum strut loads are significantly higher than those given by existing empirical design rules. Comparative analyses with an isotropic linear elastic-plastic soil model show relatively small differences in moments and strut loads. Comparisons against analyses with a beam-on-spring type finite element model show significant differences to the continuum FEM analyses. The main reason is that beam-on-spring models cannot capture the significant effect of arching on earth pressures, strut loads and bending moments.

Journal ArticleDOI
TL;DR: In this paper, a high-speed digital CCD camera was used to evaluate the deformation characteristics of models quantitatively and automatically in both static and dynamic fields, and the magnitude of seismic earth pressure was found to be influenced strongly by the seismic behavior of the backfill soil.
Abstract: A mesh-printed membrane was often used to evaluate the deformation of soil quantitatively, in bearing capacity tests or plain strain compression tests. The deformation of soil can be evaluated quantitatively by measuring the displacement of each mesh captured by taking pictures. However, this method requires much time to obtain the displacement and cannot be applied to the dynamic field, such as shaking table tests, because of the limitation of frame rate of the conventional analog camera. In this study, a new image processing system using a high-speed digital CCD camera was established to make it possible to evaluate the deformation characteristics of models quantitatively and automatically in both static and dynamic fields. Further, this system was applied to the shaking table tests on a retaining wall model, and the magnitude of seismic earth pressure was found to be influenced strongly by the seismic behavior of the backfill soil.

Journal ArticleDOI
TL;DR: In this article, an experimental investigation on the passive earth pressure of overconsolidated cohesionless soil on retaining walls was conducted, where a prototype model of a vertical rough wall, retaining horizontal backfill, was developed in the laboratory.
Abstract: An experimental investigation on the passive earth pressure of overconsolidated cohesionless soil on retaining walls was conducted. A prototype model of a vertical rough wall, retaining horizontal backfill, was developed in the laboratory. The model was instrumented to measure the total passive earth pressure acting on the wall, the passive earth pressure acting on selected locations on the wall, and the overconsolidation ratio (OCR) of the sand in the testing tank. In order to develop the state of passive pressure, the wall was pushed horizontally toward the backfill without any rotation. Overconsolidated sand was produced in the testing tank by placing the sand in thin layers; each was compacted mechanically for a period of time. Tests were performed on walls retaining homogeneous overconsolidated sand, and overconsolidated sand backfill overlying the deep sand layer. The method of slices developed for predicting the coefficient of passive earth pressure for normally consolidated soil was adopted for the conditions stated above. The theoretical values compared well with the experimental results of the present investigation. It is of interest to note that the OCR and the soil condition below the founding level significantly affect the value of the coefficient of passive earth pressure on these walls. Design charts and formulae are presented for practical use.

Proceedings ArticleDOI
31 Oct 2005
TL;DR: In this paper, the authors examined earth pressure acting on an embedded footing and its effects on pile forces, based on both liquefaction and non-liquefaction tests using a large-scale laminar shear box.
Abstract: This paper examines earth pressure acting on an embedded footing and its effects on pile forces, based on both liquefaction and non-liquefaction tests using a large-scale laminar shear box. The following conclusions are drawn: (1) The total earth pressure defined by the difference in earth pressure between passive and active sides in the non-liquefaction tests varies significantly depending on its phase relative to the soil inertia around the embedded footing as well as on the relative displacement between soil and footing; (2) The total earth pressure in the liquefaction test, by contrast, depends mainly on the relative displacement because the soil inertia gets small in liquefied soil; (3) The total earth pressure in the non-liquefaction tests tends to be out of phase by 180 degrees with the superstructure inertia, reducing the shear force and bending moment at the pile head; and (4) The total earth pressure in the liquefaction tests tends to be in phase with the superstructure inertia, making the bending moment at the pile head large. A method for estimating the total earth pressure considering its phase relative to the superstructure inertia as well as the effects of soil inertia has been proposed. The proposed method gives a reasonable explanation of the difference in earth pressure between different tests.

Journal Article
TL;DR: In this paper, a general tangential stress coefficient is introduced to overcome the limitations of the Haar Von Karman hypothesis in axi-symmetric earth pressure problem, and a simplified analytical solution of active earth pressure on circular shaft with no wall friction and horizontal backfill is developed.
Abstract: In this paper, a general tangential stress coefficient is introduced to overcome the limitations of the Haar Von Karman hypothesis in axi-symmetric earth pressure problem. A simplified analytical solution of active earth pressure on circular shaft with no wall friction and horizontal backfill is developed in the present paper. It is demonstrated that the tangential stress coefficient has a major effect on the active pressure and the Harr Von Karman hypothesis may be unacceptable in practice. The authors consider that an active earth pressure based on a tangential stress coefficient equal to the coefficient of earth pressure at rest is suitable for engineering practice.

Journal ArticleDOI
TL;DR: In this article, a method for testing the interaction between soil and shaft wall by high-pressure direct shear apparatus and triaxial servo test system has been presented, and the deformation characteristics of the interactions between soils and shaft walls during deep soil compression due to water loss are analyzed: they are elastic in the shallow and bottom parts and plastic in the deep part.
Abstract: Non-mining ruptures of shaft linings in coal mines, which have repeatedly occurred in coal mine areas of East China in recent years, are a new kind of geological disaster. In this paper the characteristics of non-mining ruptures of the shaft linings are presented. The engineering geology conditions of the ruptures are analysed. A method for testing the interaction between soil and shaft wall by high-pressure direct shear apparatus and triaxial servo test system has been presented. The shear stress– displacement curves, coefficient of unit stiffness and strength parameters of the interaction between soil and shaft wall are obtained. Combining with the test results, the deformation characteristics of the interaction between soils and shaft wall during deep soil compression due to water loss are analysed: they are elastic in the shallow and bottom parts and plastic in the deep part. An elastic perfectly plastic analysis model of the interaction between soil and shaft wall has been set up. Some analytic formu...

Book ChapterDOI
01 Jan 2005
TL;DR: In this paper, the features of different, purpose-built types of compaction probes are described and the most important factors governing the compaction process are presented, such as vibration frequency, an important parameter as it influences probe penetration.
Abstract: Planning and execution of deep vibratory compaction of natural and man-made fills requires recognition of fundamental soil aspects, such as the compactability of soils. Design is usually based on cone penetration tests and carried out with equipment specially developed for deep vibratory compaction, in particular, using variable frequency vibrators. The features of different, purpose-built types of compaction probes are described and the most important factors governing the compaction process are presented, such as vibration frequency — an important parameter as it influences probe penetration — and can enhance compaction by means of resonance effects during the compaction phase. Vibratory compaction generates lateral stresses, which result in a permanent increase of the horizontal earth pressure and overconsolidation. The practical importance of these effects is discussed.