Assessment criterion for level of liquefaction-induced lateral spread and its reliability analysis

An assessment criterion for the level of field liquefaction-induced lateral spread is created based on the liquefaction-induced lateral spread database built by Youd et al. The impact of various parameters on the level of lateral spread is studied, and the main factors are determined. A classification tree is constructed for the estimation of liquefaction-induced lateral spreads severity level (LLSL). The rationality and reliability of the criterion are verified through the analysis of changing trend and decoupling of influence factors for lateral spreads and compared with those of MLR based on the damage of actual earthquakes. The research results show that (1) The main influence factors including PGA, W_ff or S, T₁₅ and F₁₅, and the average mean grain size D50₁₅ can be removed. The sort and impact weights of these influence factors for free face condition are W_ff (0.334), F₁₅ (0.322), T₁₅ (0.176) and PGA (0.159); for gently sloping ground conditions, the results are F₁₅ (0.324), T₁₅ (0.277), S (0.214) and PGA (0.185); (2) The verification results of the proposed method are 6% higher than those of MLR, because the decoupling is considered in CART, but the influence factors are assumed to be independent in MLR. The distribution of discriminant results is relatively homogeneous, and the low success problem of MLR for the low level hazard is overcome; (3) The new method has less dependency on borehole data than MLR and more applicable to the liquefaction zoning map, which is well-matched to the current damage assessments; (4) The proposed method and criterion may provide technical support for hierarchical prediction and division map of liquefaction-induced lateral spread.