A fundamental framework for strain-space soil modelling
Abstract
In loading of soils beyond the elastic limit, the theory of plasticity is generally applied in predicting the load-deformation response. The most common approach is to use stress as the independent variable and obtain a relationship for strain. This is the stress space formulation. Modelling the strain softening behavior of clays, and relating model behavior to soil structure, have been difficult problems to approach using this formulation. An alternate approach is to use strain as the independent variable, i.e. to perform strain-space soil modelling. The development of a framework for strain space soil modelling is the purpose of this study. The major issues that are addressed include: (a) the use of strain as an admissible state variable, (b) the definition of a reference state for measurement of strain, (c) the existence of fabric-strain relationship for clays, (d) the identification of soil parameters that describe soil dilatancy behavior, and (e) the development of a yield locus in strain space. The strain space formulation allows for simplicity in expressing loading criteria, and is compatible with the most commonly used displacement based FEM analyses. In addition, the entire formulation is related to the soil structure and the internal fabric response. All the different aspects of this study are tied together in the developed strain-space soil model. The model is applied to a kaolin clay and used to examine the response of soil during pressuremeter installation and testing. It is shown that the predictions made agree well with the observations.
Degree
Ph.D.
Advisors
Altschaeffl, Purdue University.
Subject Area
Civil engineering
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