An investigation of anisotropic elastic parameters of Bangkok Clay from vertical and horizontal cut specimens

Abstract

This paper presents an investigation of cross-anisotropic elastic parameters of Bangkok Clay. The study programme consists of both laboratory experiments and parametric analysis. A set of isotropically consolidated undrained and drained triaxial compression tests is performed on vertically- and horizontally-cut undisturbed specimens. The triaxial apparatus is equipped with local strain measuring systems and bender element which enable the measurement of stiffness at small to intermediate strains. The anisotropic stiffness parameters obtained from both undrained and drained triaxial tests are assumed to follow the three-parameter cross-anisotropic elastic model proposed by Graham and Houlsby (1983). Moreover, the elastic moduli are also assumed as power functions of isotropic confining stress. The cross-anisotropic elastic parameters are then derived as functions of these relevant simplified parameters. The least-square method is used to define the optimised elastic parameters from all tests. Finally, a complete set of cross-anisotropic elastic parameters of Bangkok Clay is proposed and discussed against reported values from other soils.

Keywords:

• anisotropy
• elasticity
• local measurement
• bender element
• triaxial test
• Bangkok Clay
• optimisation

Acknowledgement

This research is a part of the first author's Ph.D. study which is supported by CHE and AUN/SEED-Net. The second author would like to appreciate the funds from the National Research University Project of the CHE and the Ratchadaphiseksomphot Endowment Fund (No. CC516A). The third author thanks the funds from the Thailand Research Fund (MRG4880055), the Faculty of Engineering at Burapha University (CA1/2551), and the National Research Council of Thailand.