Determination of geotechnical characteristic values of marine clay

Abstract

In this paper, methods of determining characteristic values for geotechnical reliability-based design were analysed for Korean marine clays. The characteristic values using the Student approach were closest to the mean value of parameters followed by the characteristic values using Ovesen, Schneider and EN 1990's approaches. Four different approaches showed a trend of evaluating characteristic values conservatively with increasing soil variability. Geotechnical stability and settlement of a breakwater, subjected to nominal stress on unimproved soft ground, were studied to investigate the effects of the estimated different characteristic values. Using Schneider's approach, the ratio of allowable bearing capacity to acting loads was 65% of that based on the arithmetic mean values, and the settlement was underestimated by 13.6%. It was also found that determining a representative value using an arithmetic mean value significantly overestimated the ratio comparing the values using the proposed approaches, which may induce an uneconomic design of structure if not considering serious soil variability owing to insufficient test data.