Implementation and Comparison of a Generalized Plasticity and Disturbed State Concept for the Load-Deformation Behavior of Foundations


1 Department of Civil Engineering,Khajeh Nasire Toosi University of Technology

2 Department of Civil Engineering,Tarbiat Modares University

3 Department of Civil Engineering,Arizona State University

4 Department of Civil Engineering,Razi University


Abstract. A nonlinear nite element method with an eight-noded isoparametric quadrilateral element
is used for the prediction of load-deformation behavior including the bearing capacity of foundations.
A Disturbed State Concept (DSC) with a Hierarchical Single-Surface (HISS) plasticity model with an
ow rule, and a Generalized Plasticity Model (GPM) with a non-associated
ow rule are used
to characterize the constitutive behavior of soils. The DSC model, however, can allow for non-associative
behavior through the use of disturbance. Both models are able to simulate load-deformation including
softening behavior. However, the GPM is based on the continuum approach while the DSC can allow
for discontinuity due to factors such as microcracking. Predictions by both models show good agreement
with laboratory data. A comparison between the DSC/HISS and generalized plasticity model is presented
and it is found that the DSC/HISS model has certain advantages over the generalized plasticity model. A
modi ed Terzaghi theory is developed for the bearing capacity based on the dependence of material behavior
and in-situ stress; it can be used to compute the bearing capacity a ected by in-situ stress.