An elastoplastic model for frictional and cohesive materials and its application to cemented sands

It has been found that the experimental results on frictional and cohesive materials such as cemented sands and unsaturated soils obtained under constant mean effective principal stress (σ_m=const.) in three-dimensional (3D) stress can be consistently arranged on the concept of the Extended Spatially Mobilized Plane (the extended-SMP), which is modified from the original SMP by introducing cohesion parameter σ₀(=c cot ϕ). Consequently, an elastoplastic model for frictional and cohesive materials is developed from the extended-SMP and the t_ij-sand model for frictional materials by taking the effect of cohesion (σ₀) into consideration. The model covers both Von Mises type model for metals (σ₀→∞) and t_ij-sand model for granular materials (σ₀=0) at two extremes. In this paper, the derivation of the proposed model, the physical meaning and determination of seven model parameters, the comparison of the model predictions with the results of triaxial compression, triaxial extension and true triaxial tests on cemented sands, and the relationship among the proposed model, the plastic theory of Mises type for metals and an elastoplastic model for granular materials, are presented. Copyright © 1999 John Wiley & Sons, Ltd.