Effective Stress-Strain-Strength Model for Soils

An analytical model is proposed that treats soil as an elastic-plastic strain-hardening or strain softening, frictional material. The formulation, which is based on the critical state model developed by Cambridge University, ties together undrained and drained loading situations, and nonlinear behavior is accounted for by specifying appropriate yield functions and using an associative flow rule. Mathematically simple but realistic yield functions are proposed to facilitate closed-form solutions. The incremental stress-strain relationships are developed for use in finite element analyses, and, as an illustration. the drained expansion of a cylindrical cavity (pressure meter test) is analyzed.