Monotonic Direct Simple Shear Tests on Sand under Multidirectional Loading

Yao Li,Gethin Roberts,Yunming Yang,Hai-Sui Yu

doi:10.1061/(asce)gm.1943-5622.0000673

Abstract

AbstractStress–strain responses of Leighton Buzzard sand are investigated under bidirectional shear. The tests are conducted by using the variable direction dynamic cyclic simple shear (VDDCSS). Soil samples are anisotropically consolidated under a vertical normal stress and horizontal shear stress and then sheared in undrained conditions by applying a horizontal shear stress acting along a different direction from the consolidation shear stress. The influence of the orientation and magnitude of the consolidation shear stress is investigated in this study. There have been only a few previous studies on soil responses under bidirectional shear, of which most studies do not consider the impact of the magnitude of the consolidation shear stress. They are compared with current studies, indicating both similarities and differences. Generally, all test results indicate that a smaller angle between the first and second horizontal shear stress leads to more brittle responses with higher peak strengths, and a larg...

Highlights

Studying soil behavior under shear stress is an important research topic in soil mechanics (Ishihara 1993; Sassa and Sekiguchi 2001; Yang and Yu 2013; Toyota et al 2014; Guo et al 2014)
To examine the general behavior of Leighton Buzzard sand, the samples are sheared to failure under undrained conditions without the consolidation shear stress under different relative densities and vertical pressures
DeGroot et al (1996), Biscontin (2001), and Rutherford (2012) performed tests on different types of clay under the consolidation shear stresses with angles ranging from 0° to 180° by using bidirectional direct simple shear apparatuses

Summary

Introduction

Studying soil behavior under shear stress is an important research topic in soil mechanics (Ishihara 1993; Sassa and Sekiguchi 2001; Yang and Yu 2013; Toyota et al 2014; Guo et al 2014). Used testing facilities are hollow cylinder and direct simple shear apparatuses. There is one salient limitation in these experiments: there is only one shear stress exerted on a soil sample. In most geotechnical engineering applications, soil is often subjected to the shear stress along multiple directions, such as in embankments under an earthquake strike and in the foundations of breakwater. The incident, reflected, and refracted waves generate multiple dimensional shear stresses on soil under breakwater. Those complex loading conditions cannot be simulated using the traditional simple shear and hollow cylinder apparatuses, which can only exert one shear stress in soil samples

Results

Discussion

Conclusion