A Simple One-Scale Constitutive Model for Static Liquefaction of Sand-Silt Mixtures

Instability of liquefaction is one of the major reasons which results in the failure of earth structure such as dam. The present study focuses on the simulation of static liquefaction behavior for granular materials such as sand and sand-silt mixtures. Based on micromechanical analysis of inter-particle behavior, a simple one-scale model is proposed to simulate the stress-strain response of sand; then the proposed model is extended to simulate the sand-silt mixtures using the mixture theory combining the properties of sand and silt according to their proportions. Empirical expressions are introduced to fit the critical state strength and the location of the critical state line for each mixture. Parameters of the model can be divided into two categories: the first seven parameters have the same values either with pure sand or pure silt for silt-sand with any given fines content; the other three parameters are the function of fines content and three more parameters are required to estimate their values. The predicted results of triaxial test of sand and sand-silt mixtures with different fine content, which has a good agreement with the results of laboratory tests, suggest that the proposed model can simulate static liquefaction behavior of sand and sand-silt mixtures.