A Ong Yin Hoe creator Kyung-Ho Park Chairperson Bergado, Dennes T. Examination Committee Noppadol Phien-Wej Examination Committee AIT partial scholarship Scholarship donor text series technical report th Pathum Thani, Thailand Asian Institute of Technology 2004 continuing eng 119 leaves The study focuses on the application of a simple, unified clay and sand model (called CASM) to Bangkok clay and Ayuttaya sand, and the numerical implementation into the well-known CRISP program. The model requires seven parameters. The parameter values are obtained from the previous testing results conducted in AIT, for normally and over-consolidated Bangkok clay. Several triaxial tests are carried out to estimate the parameter values for Ayuttaya sand. In order to check the applicability, the Excel program is developed and the simulated results are compared with the testing results. The model is also implemented into CRISP program. Although CASM originally uses the non-associated flow rule, associated flow rule is applied for programming because CRISP uses a symmetric frontal solver for equation solution. The detailed explanation of derivation of the incremental elasto-plastic stress-strain matrix is given. The developed program is verified by the simulation of triaxial tests. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology Thesis (M.Eng.) - Asian Institute of Technology, 2004 Clay Thailand Phra Nakhon Si Ayuthaya Sand Thailand Phra Nakhon Si Ayuthaya Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B09084 http://203.159.5.9/ait-thesis/detail.php?q=B09084 041226 20260818223314.0