Pre-failure stress-strain behavior and strength of Bangkok Clay

Abstract

Many recent research works have suggested that the stress-strain behavior of soil is highly non-linear and the small strain stiffness of soil is very important for the analysis of the boundary value problems. Although, there are a lot of studies on the behaviors of Bangkok Clay, there is not data on the stress-strain behavior at small- and intermediate-strain level from local strain measurement available at present. This research aims to investigate the stress-strain non-linearity behavior of undisturbed sample of Bangkok Clay with particular attention to its small- and intermediate-strain behavior and also anisotropic characteristic by using the conventional triaxial apparatus incorporating with the local strain measurement systems and bender element system. Both of isotropically consolidated undrained and drained compression tests (CIUC/CIDC) were performed on the vertically and horizontally cut specimens in order to study anisotropic characteristic. Moreover, this research also studies the effects of principal stress rotation and intermediate principal stress on undrained behavior of Bangkok Clay. The results of torsional shear hollow cylinder with various principal stress directions and various magnitude of intermediate principal stress on undisturbed Bangkok Clay are presented. These experimental results should provide further understanding about Bangkok Clay behavior and be also useful for the development of new constitutive models for Bangkok Clay.