Statistical Analysis of Sand Liquefaction

A consistent set of stochastic models is developed for the liquefaction resistance of a homogeneous mass of sand, such as a laboratory sample or small element of in situ material. A probabilistic model for liquefaction in the laboratory for undrained simple shear tests is developed first. This model gives the probability distribution of the number of cycles to liquefaction as a function of uniform shear stress amplitude, mean initial effective stress, and relative density. Corrections are quantified and incorporated into the model. Parameters are estimated from a large number of simple shear test results obtained by eight different groups of researchers using several sands and testing techniques. The laboratory liquefaction model is converted into one applicable in the field. Finally, the model is generalized to load cycles with nonuniform shear stress amplitude.