A state-dependent soil model and its application to principal stress rotation simulations

Zhongtao Wang,Peng Liu,Andrew Hin Cheong Chan

doi:10.1177/1550147718808751

Abstract

The plastic strain caused by principal stress rotation is one of the most important factors contributing to substantial deformation under earthquake, wave or traffic loading. The original Pastor–Zienkiewicz Mark III model, a well-known model for the analysis of the dynamic response under cyclic loading, is unable to consider the effects of principal stress orientation as well as state-dependent dilatancy. In this article, a new constitutive model for sand is developed to consider both aforementioned effects based on the original Pastor–Zienkiewicz Mark III model. There are 14 model parameters in total for the static condition and three extra parameters for cyclic loading, and a corresponding calibration method of model parameters is proposed. The predictive capability of the proposed model is verified with the results of a series of experiments on sand, including undrained monotonic tests in different fixed principal stress orientations and undrained cyclic rotational shear tests. The comparisons indicate that the proposed model can effectively incorporate the effects of principal stress orientation and state-dependent dilatancy.

Highlights

The phenomenon of principal stress rotation is very common in sea-floor sediments under wave loading and foundations under earthquake loading or traffic loading.[1,2] models formulated under the traditional plasticity theory in principal stress space cannot reflect the principal stress rotation effect
Many experimental results[3,4,5] have shown that either the principal stress rotation in cyclic rotational shear tests or the fixed principal stress orientation variation in monotonic loading tests has a significant impact on stress–strain behaviour of sand
A new constitutive model is developed in this article by introducing (a) predicted result by the PZ3 model

Summary

Introduction

The phenomenon of principal stress rotation is very common in sea-floor sediments under wave loading and foundations under earthquake loading or traffic loading.[1,2] models formulated under the traditional plasticity theory in principal stress space cannot reflect the principal stress rotation effect. Following this course of studies and within the framework of generalized plasticity, a new constitutive model to reflect both the effects of principal stress orientation and state-parameter dependency is proposed and formulated in section ‘Model description’.

Results

Conclusion