Influence of Intermediate Principal Stress on Undrained Behavior of Intact Clay under Pure Principal Stress Rotation

Jian Zhou,Xiaonan Gong,Jiajia Yan,Changjie Xu

doi:10.1155/2013/950143

Abstract

This study presents the accumulations of the excess pore water pressure and the deformation as well as the noncoaxial behavior of intact soft clay subjected to pure principal stress rotation. Series of tests were carried out by using a dynamic hollow cylinder apparatus to highlight the influence of intermediate principal stress parameterb. It was found that the rate of PWP evolution was greatly influenced byb, but the influence was not monotonous. Specimens under the conditionb= 0.75 had the highest accumulation of pore water pressure while under the conditionb= 0 had the strongest resistance to the pore pressure generation. PWP accumulated mainly in the first cycle. The failure of specimens under principal stress rotation was controlled by the strain other than the pore pressure. The shear stiffness decreased more quickly with higherbvalue. The direction of the principal strain increment was strongly dependent on the principal stress increment orientation and less influenced by thebvalue and the number of cycles.

Highlights

Loading conditions in geotechnical engineering are very complex; in laboratory test and numerical analysis the stresses on the soil elements need to well represent the real situation
The main objective of this study is to investigate the influence of b on the responses of intact soft clay under the pure principal stress rotation
The shear stress q was constant in pure rotation tests, significant pore water pressure (PWP for short) accumulated with the principal stress rotation (Figure 5), which surely demonstrated the effect of the intermediate principal stress

Summary

Introduction

Loading conditions in geotechnical engineering are very complex; in laboratory test and numerical analysis the stresses on the soil elements need to well represent the real situation. In many scenarios, such as earthquakes, vehicular traffic, and ocean waves [1,2,3], the magnitude of principal stresses and the direction will change. The results showed that the shear strength, the pore pressure parameter, and the frictional angle of soils are highly dependent on the magnitude of b [10,11,12,13,14,15,16]

Objectives

Results

Conclusion