Abstract: The existing methods are mainly expressed in equation form for evaluating the soil liquefaction, among which the equation of liquefaction probability evaluation method is particularly complicated and conservative. However, for the liquefaction microzoning of large-area and multi-points, objective and simple methods are needed. Therefor an optimized Logistic liquefaction probability equation and the corresponding tabular liquefaction probability evaluation method were developed. According to the published results of shear wave velocity liquefaction field in-site tests, the liquefaction probabilities of samples were calculated as the basis for grading the liquefaction possibility, and three precision liquefaction probability criteria tables were constructed by decision tree method. Then the data set constructed by Kayen et al. was used as the judgment data set. The differences between the optimized equation and Kayen’s liquefaction probability equation were compared to meet the purpose of measuring the reasonableness of the optimized equation and criteria tables. The results show that the influence of misjudgment by the optimized equation on actual engineering is less than Kayen’s equation. All the three criteria tables can properly isolate more than 70% of the sites, and the evaluation of liquefied site and non-liquefied site are both well considered. The criteria tables simplify the evaluation process of liquefaction probability, improve the applicability of shear wave velocity liquefaction probability evaluation method, and realize the purpose of evaluating liquefaction probability without calculation. The tabular method will provide support for liquefaction microzoning based on shear wave velocity.

Key words: liquefaction probability grades, decision tree, rank of importance of liquefaction factors, shear wave velocity