Three-dimensional analysis of a pile-group foundation

Muqtadir, A.; Desai, C. S.

doi:10.1016/0148-9062(86)90800-4

Cited by 14 publications

(17 citation statements)

References 1 publication

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“…A similar problem is encountered in critical state soil mechanics in modeling the shearing behavior of sands from the overconsolidated or underconsolidated state toward the critical state at which shear strength and porosity remain constant. In soil mechanics, this evolution is usually modeled using a discrete element approach to granular flow [Brown and Shie, 1990;Chen and Martin, 2002;Muqtadir and Desai, 1986;Yang and Jeremic, 2002] but such approaches have so far been restricted to considering mainly elastic/frictional interactions between grains. We have therefore chosen to establish a very simple set of microstructural equations relating tan y and A c to porosity f. While these are clearly oversimplifications, and may not be fully internally consistent with the assumed microstructural model, they embody the trends known to occur in granular media and they satisfy a number of crucial microstructural constraints, as shown below.…”

Section: Microstructural Model and Associated State Variablesmentioning

confidence: 99%

A microphysical model for strong velocity weakening in phyllosilicate‐bearing fault gouges

2007

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[1] Previous rotary shear experiments, performed on a halite-muscovite fault gouge analogue system have shown that the presence of phyllosilicates, under conditions favoring the operation of cataclasis and pressure solution in the matrix phase, can have major effects on the frictional behavior of gouges. While 100% halite and 100% muscovite samples exhibit rate-independent frictional/brittle behavior, the strength of mixtures containing 10-30% muscovite is both normal stress and sliding velocitydependent. At high sliding velocities (>1 mm s À1 ), such mixtures show unusually marked velocity weakening, along with the development of a structureless, cataclastic microstructure. In the present paper, a micromechanical model is developed in an attempt to explain this behavior. The model assumes a granular flow process involving competition between intergranular dilatation and compaction by pressure solution. The predictions of the model agree favorably with the experimental results. Extension of the model to quartz-mica systems implies that the presence of phyllosilicates plus the operation of pressure solution can strongly promote (unstable) velocity-weakening behavior at rapid slip rates on natural faults, under midcrustal conditions. Static stress drop predictions based on the model agree reasonably well with estimates from seismic observations. Our results may help explain the discrepancy between laboratory-derived rate-and-state friction parameter values, obtained for dry, low-strain and/or single-phase rock systems, and the values for natural fault rocks inferred from seismological data.Citation: Niemeijer, A. R., and C. J. Spiers (2007), A microphysical model for strong velocity weakening in phyllosilicate-bearing fault gouges,

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Section: Microstructural Model and Associated State Variablesmentioning

confidence: 99%

A microphysical model for strong velocity weakening in phyllosilicate‐bearing fault gouges

2007

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“…Generally, pile-group foundations involve three-dimensional interaction among the pilecap, soil and piles. In the past, problems that arose because of these interactions had been often solved by making simplifying assumptions regarding the geometry and the properties of the materials used [4]. However, because of the realistic nature of the problem, it has become essential to allow for threedimensional geometry, interface effects and non-linear soil properties.…”

Section: Introductionmentioning

confidence: 99%

“…Jun Ju [17] and Fuchun et al [18] have carried out settlement analysis using PLAXIS 3D finite element package for pilegroups located in sleech strata and soft clayey soil respectively. Alnuiam et al [19] and Muqtadir [4] have conducted a non-linear three-dimensional finite element analysis of sand to capture the deformation behaviour of pile-groups. Jian-lin et al [1] have conducted a settlement analysis of pile-groups located in deep clayey soil deposits and have proposed a valuable equation to correct the compression modulus of soil during the simulation of deep soil conditions.…”

Section: Introductionmentioning

confidence: 99%

Three - dimensional Numerical Simulation and Validation of Load-settlement Behaviour of a Pile Group under Compressive Loading

Gowthaman

Nasvi

2018

Engineer

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Abstract:Settlement of pile foundation is one of the controlling pile design parameters and its numerical simulation is one of the techniques widely used to predict the settlement behaviour of piles. This study was on the settlement behaviour of a pile group located in silty-sand deposits using the finite element (FE) approach which is based on the static pile load test. Three different types of analyses were investigated: (1) a linear elastic (LE) analysis in which the soil was assumed to be linear elastic, (2) a complete nonlinear analysis in which the soil adjacent to the pile shaft as well as the soil between the piles were modelled using the Mohr Coulomb (MC) or hardening soil (HS) model, and (3) a combined analysis in which the soil close to the pile shaft was modelled using the HS model while the soil in the remaining area was modelled using the LE or MC model. Numerical results obtained for the load-settlement behaviour of the pile group were validated using the popular RATZ analytical approach. The results of the FE analysis suggest that incorporating a nonlinear zone of soil close to the pile shaft as an interface and leaving the soil beyond this zone as linear elastic give a more reasonable estimation and a much better prediction of the pile group settlement. It is also suggested that for a typical pile group, a nonlinear interface of thickness equal to the pile diameter and extending from the pile shaft to the edge of the zone would be sufficient to capture the load transfer mechanism. The group settlement ratio predicted in this study is in good agreement with the findings made in the previous studies.

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“…Continuously, many researchers [5][6][7][8][9][10][11][12][13] have conducted analytical study for the vertical deformation of pile foundations using different techniques such as theoretical load-transfer curves, discrete layer approach, elastic solutions, theory of pile-soil interactions and hybrid approaches. However, in this method, problems have often been solved by making number of simplifying assumptions regarding the geometry and material properties [14].…”

Section: Introductionmentioning

confidence: 99%

2D and 3D Numerical Simulation of Load-Settlement Behaviour of Axially Loaded Pile Foundations

Gowthaman¹,

Mcm²

2017

AJCEA

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Reliable prediction of settlement behaviour of axially loaded piles is one of the major concerns in geotechnical engineering. Therefore, this paper focuses on the finite element solutions of load-settlement behaviour of a single pile and pile group using PLAXIS numerical package. Three different types of analysis were incorporated: a linear elastic analysis, a complete nonlinear analysis and a combined analysis. The pile case history with settlement measurements made during field pile load test was considered to validate the single pile load-settlement simulation, and the same load test result was extended to simulate the load-settlement behaviour of pile group using RATZ analytical approach. The single pile analysis results suggest that realistic load-settlement predictions can be drawn by considering complete soil as Mohr-Coulomb model at lower working loads, and incorporation of an interface zone thickness of two times pile diameter using Hardening-Soil model is required to simulate the load-settlement behaviour at higher working loads. The group pile analysis results provide a better load-settlement prediction when incorporating an interface zone thickness of pile dimeter from the pile shat using Hardening-Soil model while leaving the remaining soil as Linear-Elastic material.

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Three-dimensional analysis of a pile-group foundation

Cited by 14 publications

References 1 publication

A microphysical model for strong velocity weakening in phyllosilicate‐bearing fault gouges

A microphysical model for strong velocity weakening in phyllosilicate‐bearing fault gouges

Three - dimensional Numerical Simulation and Validation of Load-settlement Behaviour of a Pile Group under Compressive Loading

2D and 3D Numerical Simulation of Load-Settlement Behaviour of Axially Loaded Pile Foundations

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