Evaluation of Undrained Shear Strength of Pusan Clay Using in-situ Tests

Abstract

Busan clay, usually varying from 20 to 70m thick, is widely deposited along the coastline in the Nakdong River deltaic area located west of Busan City in Korea. Despite many geotechnical investigations for various reclamation projects, the properties of the clay have not been yet elucidate due to their spatial variation and inadequate undisturbed sampling. The undrained shear strength of the clay is interpreted using the flat dilatometer (DMT) with various existing empirical equations. The results are compared with each other, and correlated with the corrected undrained shear strength obtained from the field vane shear test (Su(FVT)). The results indicated that the KD–based empirical equation proposed by Marchetti (1980) slightly underestimates the Su(FVT) values on the clay.Empirical equations based on Su-KD and Su-ED-ID relationshipsare developed for the clay. The undrained shear strengths estimated from theSu-ED-ID relation give the closest correlation.