Finite element dynamic analysis of nonlinear porous media with applications to piles in saturated clays.

Persistent Link:
http://hdl.handle.net/10150/185068
Title:
Finite element dynamic analysis of nonlinear porous media with applications to piles in saturated clays.
Author:
Wathugala, Gamage Wijesena.
Issue Date:
1990
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
A basis for developing a general approach to solve geotechnical engineering problems through dynamic finite element analysis of nonlinear porous media is presented. A new series of constitutive models named here as δ* series are developed under the general hierarchical single surface (HISS) modeling approach, to include the behavior of, saturated normally consolidated and overconsolidated clay, under drained or undrained, static and cyclic loading conditions. Algorithms for determination of material parameters for these models from laboratory models are also developed. Constitutive parameters for Sabine Clay are obtained using triaxial test results from undisturbed samples and the model is verified by back predicting the laboratory behavior of this clay. Sensitivity analyses for all the material parameters have been also carried out. Efficient and reliable algorithms for calculating strain increments for given stress increments and vice versa are developed. All the models in the δ* series are implemented in the finite element program POROUS which is based on the theory of dynamics of nonlinear porous media. Here a modular approach is used to facilitate easy modification of all the functions associated with these models (yield function, potential function, hardening function and interpolation functions). Complete test procedure for field load tests on two pile segments (3 inch and 1.72 inch) are numerically simulated and compared with field measurements. Initial stresses before pile driving are estimated using results of s self boring pressuremeter test on the site. Strain distributions just after pile driving are evaluated using the strain path method. The effective stress distribution is obtained by integrating constitutive equations for given strain paths. Corresponding total stresses and pore pressure distributions are obtained using the computer program POROUS. Consolidation after pile driving and all the static and cyclic tests followed are also simulated using the program POROUS. The predicted normalized pore pressure dissipation curve matches the field behavior. This analysis provides good predictions of shear transfer from which the pile capacity can be evaluated. Even though the variation of pore pressure during a cycle is not matched exactly, the accumulation of pore pressures are predicted well. The demonstrated ability of dynamic finite element analysis of nonlinear porous media, to simulate slow consolidation and cyclic load tests provides a basis for developing a general approach for solving geotechnical engineering problems.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Finite element method; Applied Mechanics; Geotechnology; Porous materials -- Numerical analysis; Piling (Civil engineering) -- Numerical analysis; Clay -- Analysis.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Civil Engineering and Engineering Mechanics; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Desai, Chandra S.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleFinite element dynamic analysis of nonlinear porous media with applications to piles in saturated clays.en_US
dc.creatorWathugala, Gamage Wijesena.en_US
dc.contributor.authorWathugala, Gamage Wijesena.en_US
dc.date.issued1990en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractA basis for developing a general approach to solve geotechnical engineering problems through dynamic finite element analysis of nonlinear porous media is presented. A new series of constitutive models named here as δ* series are developed under the general hierarchical single surface (HISS) modeling approach, to include the behavior of, saturated normally consolidated and overconsolidated clay, under drained or undrained, static and cyclic loading conditions. Algorithms for determination of material parameters for these models from laboratory models are also developed. Constitutive parameters for Sabine Clay are obtained using triaxial test results from undisturbed samples and the model is verified by back predicting the laboratory behavior of this clay. Sensitivity analyses for all the material parameters have been also carried out. Efficient and reliable algorithms for calculating strain increments for given stress increments and vice versa are developed. All the models in the δ* series are implemented in the finite element program POROUS which is based on the theory of dynamics of nonlinear porous media. Here a modular approach is used to facilitate easy modification of all the functions associated with these models (yield function, potential function, hardening function and interpolation functions). Complete test procedure for field load tests on two pile segments (3 inch and 1.72 inch) are numerically simulated and compared with field measurements. Initial stresses before pile driving are estimated using results of s self boring pressuremeter test on the site. Strain distributions just after pile driving are evaluated using the strain path method. The effective stress distribution is obtained by integrating constitutive equations for given strain paths. Corresponding total stresses and pore pressure distributions are obtained using the computer program POROUS. Consolidation after pile driving and all the static and cyclic tests followed are also simulated using the program POROUS. The predicted normalized pore pressure dissipation curve matches the field behavior. This analysis provides good predictions of shear transfer from which the pile capacity can be evaluated. Even though the variation of pore pressure during a cycle is not matched exactly, the accumulation of pore pressures are predicted well. The demonstrated ability of dynamic finite element analysis of nonlinear porous media, to simulate slow consolidation and cyclic load tests provides a basis for developing a general approach for solving geotechnical engineering problems.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectFinite element methoden_US
dc.subjectApplied Mechanicsen_US
dc.subjectGeotechnologyen_US
dc.subjectPorous materials -- Numerical analysisen_US
dc.subjectPiling (Civil engineering) -- Numerical analysisen_US
dc.subjectClay -- Analysis.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineCivil Engineering and Engineering Mechanicsen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorDesai, Chandra S.en_US
dc.contributor.committeememberDaDeppo, D.A.en_US
dc.contributor.committeememberKiousis, Panos D.en_US
dc.identifier.proquest9025087en_US
dc.identifier.oclc704413548en_US
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