Influence of Confining Stress on the Small Strain Stiffness of a Residual Soil under K 0 Conditions

Most previous studies have focused on the small strain stiffness of sedimentary soil while little attention has been given to residual soils with different properties. Most studies also neglected the effects of the deviator stress, which is extensively involved in civil engineering. This note considers the effects of the deviator stress on the small-strain stiffness of natural granite residual soil (GRS) as established from resonant column tests performed under various stress ratios. Although increasing the stress ratio results in a greater maximum shear modulus for both natural and remolded residual soils, remolded soil is more sensitive to changes in the stress ratio, which highlights the effects of soil cementation. The data herein offers new insights to understand the stiffness of residual soil and other weathered geomaterials.

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Small Strain Stiffness of Artificially Cemented Soft Clay: Modelling the Effect of Structure Degradation

E3S Web of Conferences ◽

10.1051/e3sconf/20199211009 ◽

2019 ◽

Vol 92 ◽

pp. 11009

Author(s):

Qasim Khan ◽

Yannick Ng ◽

Taeseo Ku

Keyword(s):

Soft Clay ◽

Small Strain ◽

Kaolin Clay ◽

Bender Elements ◽

Confining Stress ◽

Soft Clays ◽

Small Strain Stiffness ◽

Structure Degradation ◽

Before And After ◽

Vertically Aligned

This paper presents a study on the evolution of small strain stiffness (Gmax) along vertical and horizontal directions for lightly cemented clay. Soft clays have historically been a subject for studying the evolution of stiffness anisotropy under varying loading conditions. These studies have focused on stress history (overconsolidation) effects as well. However, for lightly cemented clays, such studies are limited and their main scope has primarily been on the evolution of vertically aligned stiffness (GVH) at varying effective confining stresses. This study investigates the effect of isotropic loading on uncemented and lightly cemented kaolin clay. Kaolin clay mixed with 10% cement is used in this study. Stiffness measurements have been conducted using bender elements for obtaining GVH and GHH hence resulting in the measurement of vertical and horizontal stiffness values respectively. By comparing the behaviour of both samples, the influence of bonding and fabric due to cementation on the evolution of stiffness and anisotropy is studied. In order to characterize the behavior of structure in cemented soil with confining stress, a modelling equation is applied for the cemented sample to predict the variation of Gmax before and after yielding.

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