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 const ant mean effective principal stress (sigma(m) = const.) in three-dimensiona l (3D) stress can be consistently arranged on the concept of the Extended S patially Mobilized Plane (the extended-SMP), which is modified from the ori ginal SMP by introducing cohesion parameter sigma(o)(= c cot phi). Conseque ntly, an elastoplastic model for frictional and cohesive materials is devel oped from the extended-SMP and the t(ij)-sand model for frictional material s by taking the effect of cohesion (sigma(o)) into consideration. The model covers both Von Mises type model for metals (sigma(o) --> infinity) and t( ij)-sand model for granular materials (sigma(o) = 0) at two extremes. In th is paper, the derivation of the proposed model, the physical meaning and de termination of seven model parameters, the comparison of the model predicti ons with the results of triaxial compression, triaxial extension and true t riaxial tests on cemented sands, and the relationship among the proposed mo del, the plastic theory of Mises type for metals and an elastoplastic model for granular materials, are presented. Copyright (C) 1999 John Wiley & Son s, Ltd.