CHARACTERIZATION OF YANGSAN CLAY, PUSAN, KOREA

HIROYUKI TANAKA , OSAMU MISHIMA , MASANORI TANAI, SUNG-ZAE PARK, GYEONG-HWAN JEONG and JACQUES LOCAT

ABSTRACT It has been reported by previous researchers that the preconsolidation pressure (p_c) of Kimhae (Yangsan) clay, which is thickly deposited along the Naktdong River, Pusan, Korea, is considerably less than its in-situ effective over-burden pressure (p'_vo). The question has arisen whether such a low p, value is due to underconsolidation or to the unreliability of laboratory tests, including the use of low quality sample. As a cooperative research program between PHRI (Port and Harbour Research Institute) and Pusan National University, extensive in-situ and laboratory investgations were carried out at Yangsan, using a Japanese sampler and Japanese sampling technique. It is found that the p* values at the site are slightly greater than p'_vo, which is different from the test results from the previous researchers. However, the overconsolidation ratio (OCR) at this site is quite small compared to similar aged normally consolidated clays deposited in Japan.

Key words: consolidation, consolidation yield stress, in-situ test, microstructure, overconsolidation ratio, Pusan clay, sample disturbance, sensitivity (IGC: C6)