UH model for granular soils considering low confining pressure

Abstract

The mechanical behaviors including strength and isotropic compression of granular soils under low confining pressure are systematically analyzed. The compressive hardening parameter ps is introduced in semi-logarithmic coordinates to express the curved normal compression line of granular soils in the e-ln p plane, to describe the little compressibility of granular soils under low confining pressure. The nonlinear variation of critical friction angle with confining pressure is considered by introducing the interlocking strength parameter τ0 into strength criteria. Based on the unified hardening model for clays and sands (CSUH model), the unified hardening (UH model) for granular soils considering low confining pressure, called UH-L model, is established. The UH-L model behaves significantly different with the CSUH model under low confining pressure, while tends to be same as the CSUH model with increasing confining pressure. The relationship between parameter ps and τ0cotφ, as well as the effect of ps and τ0cotφ on model performance are analyzed. Good agreement with the experimental data shows that the UH-L model is capable of uniformly describing the stress–strain relations and strength of granular soils with interparticle locking over a wide confining pressure load range, especially at low confining pressure.