CONSTITUTIVE MODELS FOR SOILS IN LANDSLIDES
Abstract
The present study is a part of a complete research program currently underway at Purdue University concerning studies on earthquake-induced landslides. The ultimate goal of the overall research is to devise the means and develop the capabilities for the proper assessment of the danger of slope failures and landslides. A valid assessment of this hazard requires the complete progressive failure analysis of specific soil slope problems under static as well as dynamic loading conditions. In turn, this requires the application of suitable constitutive relations characterizing the soil behavior under different types of loading. The work in this thesis focuses mainly on such stress-strain relations for soils under general multi-axial stress conditions, especially the cyclic type of loading as encountered during earthquakes. While a large variety of constitutive models for soils have been developed in recent years for use in earthquake geotechnical engineering problems, the relative advantages and disadvantages, the limitations and ranges of applications of these models have not been evaluated critically, particularly as they apply to soil instability problems. This is the main objective of the present study. In particular, the present work attempts to critically assess and evaluate several existing soil constitutive models within the context of their use in the numerical analysis of slope failure and landslides under the cyclic straining conditions induced by earthquake loadings. This includes various elasticity- and plasticity-based models. The evaluation of various models considered in this thesis is based on the following considerations: (1) Theoretical evaluation of the models with respect to the basic principles of continuum mechanics to ascertain their consistency with the theoretical requirements of continuity, stability, and uniqueness. (2) Experimental evaluation of the models with respect to their suitability to fit experimental data from available tests, and the ease of determining the material parameters from "standard" test data. (3) Numerical and computational evaluation of the models with respect to the facility with which they can be implemented in finite element computer codes. Although emphasis here is placed on the applications of the models to soil slope problems under earthquake loading, the merits and limitations of models when utilized under other circumstances (for example, in problems involving monotonic or proportional loadings) will be identified throughout the discussions. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of school.) UMI
Degree
Ph.D.
Subject Area
Civil engineering
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