Method for predicting in-situ undrained strength of highly organic soil based on the value of suction and unconfined compressive strength

A series of tests simulating the process from sampling to unconfined and triaxial compression test for highly organic soil consolidated under anisotropic stress condition is performed, and the influence of stress release and mechanical disturbance of specimen on the undrained strength is examined. A practical method for predicting in-situ undrained strength from the relationship between residual effective stress obtained by suction measurement and unconfined compressive strength is proposed. From the test results, it has been found that the strengths obtained from unconfined compression test can be reasonably corrected to estimate in-situ strengths by applying a simplified method.