A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand

Thesis (M.Eng.) - Asian Institute of Technology, 1977

This study is aimed at the evaluation of undrained shear strength, compressibility and modulus characteristics of Bangkok Clays using concepts and procedures of the theory of Statistics. Data from Laboratory and field tests are taken from previous work carried out at the Asian Institute of Technology. In-situ undrained shear strength is determined using Vane Shear and Dutch Cone tests. Distribution functions of the parameters are investigated and regression equations are obtained for the variation of in-situ strength with depth at different sites. Laboratory test data are used to determine empirical relationships for the prediction of UU Triaxial Strength, UU and CU Direct Shear Strength and Unconfined Compression Strength in terms of the variables associated with the measurements. Profiles of undrained shear strength are determined in the form of simple regression equations of effective overburden pressure and comparisons are made in relation to the different types of tests. Data from consolidation tests are used to establish regression equations for the prediction of compression index All types of test data are used in the evaluation of index properties with depth at different sites. Factor analysis technique is used to verify the results obtained from multiple regression and stepwise regression analyses, Modulus of elasticity and Poisson's ratio characteristics are studied using CU Triaxial test data for the samples taken at Nang Ngoo Hao Site. Both triaxial extension and compression tests are used with a wide variety of applied stress paths carried out on weathered, soft and stiff Bangkok Clays. A unique behaviour of the normalized modulus and Poisson's ratio with deviator stress and the stress ratio over all types of stress paths is obtained, A contribution to the development of a unique surface in normalized modulus, Poisson's ratio and the stress ratio space is thus made. The results of this study would successfully be used in stress distribution and settlement analysis.