Dynamic UH model

UH model for overconsolidated clay is extended to a dynamic UH constitutive model considering the stress-strain relationship for both clay and sands by adopting rotational hardening rule. Dynamic UH model is aimed at the stress-induced anisotropy for the both clay and sands under dynamic loading condition. Three aspects are revised in this paper. First, the fixed shape of ellipse yielding surface is revised as the changed shape of yielding surface. The value of β is used to describing the shape of yielding surface. The value for rotational axis of yielding surface can be denoted by β, which means the degree of stress-induced anisotropy. Second, the constitutive relationship for the both clay and sandsoils under reversing loading condition can be simulated by introducing rotational hardening. Third, the unified hardening parameter is revised by adding a parameter a for adjusting the overconsolidated stress ratio R which can influence the value of potential strength. The extended unified hardening parameter with considering rotational hardening and isotropic hardening is established for aiming at stress-induced anisotropy. The comparison results between model predictions and test results and the simulated results by FEM indicate the simplicity and reasonability of the proposed model which can be used to describe the constitutive relationship for both clay and sandsoils under dynamic loading condition.