Abstract: Seismic soil liquefaction problem in the soil site of nuclear power plants is a crucial point for the nuclear power plant siting. Therefore, it is urgent to develop a seismic soil liquefaction assessment procedure suitable for the soil site of nuclear power plants. The standard penetration test (SPT) and peak ground acceleration (PGA) based assessment method of soil liquefaction potential is reviewed. The basic principle to determine liquefaction triggering curve is proposed. Three corresponding liquefaction triggering correlations are derived respectively from the Idriss and Boulanger liquefaction case history database, the database of Chinese Code for Building Seismic Design and the two combined databases to reduce the possibility of mistaking liquefaction data points as no-liquefaction data points. The positions of the derived liquefaction triggering correlations are verified with respect to many factors including fines content, overburden stress and standard penetration test (SPT) procedures. In addition, the sensitivity of the database’s interpretation to a number of aspects and components of the analysis framework is examined. The results show these factors have a slight effect on the position of the proposed liquefaction triggering correlations. At last, the relationship among the nominal factor of safety and the probability of liquefaction as well as the probabilistic contours for the proposed liquefaction triggering correlation is given on the basis of Monte Carlo simulation, the weighted maximum likelihood technique and a weighted empirical probability approach. The soil liquefaction triggering correlations are proposed for the soil sites of seismic design categoryⅠ, Ⅱand Ⅲ of the structure, system and component of nuclear power plants, respectively.

Key words: soil site of nuclear power plants, soil liquefaction assessment, determinative assessment, probability assessment, liquefaction triggering curve, standard penetration test (SPT), peak ground acceleration