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, 1993

The influence of the stress history and the stress condition during consolidation and shearing were studied experimentally under undrained triaxial compression and extension conditions, by using the Recompression and SHANSEP techniques. Total twenty-two (22) triaxial tests were performed in two series such that ten (10) samples were tested using the SHANSEP technique and remaining were performed using the Recompression technique. In each series of tests, the samples were subjected to undrained shear in both extension and compression modes. The basis of SHANSEP technique derives from the concept of normalized soil parameters. The results are expressed in terms of Normalized Soil Properties (NSP). In the Recompression technique, the samples are directly reconsolidated to in-situ effective stress condition to obtain the undrained shear strength. Test results of this study include soil properties, consolidation characteristics, and stress-strain-strength deformation behavior, From the consolidation tests, the data show that the relationship between K0 and OCR of soft Bangkok clay is (K0)oc = 0.607OCR0.333. The compression curves obtained in this study are in close agreement with the1-D consolidation data presented by HASSAN (1993). The reconsolidation pressure obtained from SHANSEP tests provide almost the same values as in the oedometer tests, Shearing test result indicate that the stress-strain-strength behavior is slightly different for these two reconsolidation techniques, with Recompression giving higher Su values that the SHANSEP tests, In addition, the Recompression tests give modulus two times higher than the SHANSEP tests.