关键词: 非基岩核电厂场址, 土体液化判别, 确定性方法, 概率方法, 液化临界曲线, 剪切波速, 地表峰值加速度

Abstract: As a fundamental parameter of soil, the shear wave velocity (denoted VS)offers a means to determine the seismic resistance of soil to liquefaction. The historical developments of VS and peak ground acceleration (denoted PGA)——based assessment method of soil liquefaction potential is reviewed. The basic principle to determine liquefaction triggering curve is given. The corresponding liquefaction triggering curve is proposed based on the database used by Kayen, Andrus, Saygili and Chu for a total of 49 earthquakes, 618 case histories. The position of liquefaction triggering curve is verified with respect to various factors based on the case history database, such as fines content, overburden stress and magnitude scales. In addition, the sensitivity of the database’s interpretation to a number of aspects and components of the analysis framework is examined, such as the shear stress reduction factor that accounts for the dynamic response of the soil profile, the magnitude scaling factor, the overburden correction factor for cyclic stress ratio. And the results show these factors have slight effects on the position of the proposed liquefaction triggering curve. At last, the relationship between nominal safety factor and probability of liquefaction as well as the probabilistic contours for the proposed liquefaction triggering curve are given based on Monte Carlo simulation, the weighted maximum likelihood method and weighted empirical probability data. The soil liquefaction triggering curves are proposed for the seismic design category Ⅰ、Ⅱ and Ⅲ of the structure, system and component of nuclear power plants, respectively. The presented assessment is provided with wide application prospects.

Key words: the soil site of nuclear power plants, soil liquefaction assessment, deterministic assessment, probability assessment, liquefaction triggering curve, shear wave velocity, peak ground acceleration