Probabilistic approach for quantification of uncertainties in shear wave velocities and hazard calculation of liquefiable soil

Uncertainties governing soil parameters indicate that liquefaction in loose, saturated, sandy soils is related to probabilistic nature of these parameters. Hence, statistical approaches and especially the reliability analysis are often used as an alternative to the deterministic methods and as a powerful solution to the problem of liquefaction hazard analysis. In this paper, the method of jointly distributed random variable is used to evaluate the probability of soil liquefaction potential. The corrected shear wave velocity (V_s), peak horizontal earthquake acceleration ratio (α), and earthquake magnitude (M_w) are considered as stochastic parameters which are modeled using a normal probability density function. In contrast to the most of the past studies, the seismic parameters (M_w, α) are here assumed to follow the normal distribution leading to results which are more logically comparable with other concepts, especially those which are based FORM & FOSM & PEM. Further, a formula proposed by Idriss 1999 for variation of parameter r_d is used in the current study which is based on the earthquake magnitude M_w and depth. This further enables the authors to reduce the number of selected parameters to three. In order to study the performance of the proposed method, the liquefaction potential of Taiwan’s Yuanlin region, affected by Chi-Chi earthquake, has been studied. The results show the effectiveness and speed of calculation of the proposed method.