Modeling the cyclic undrained behaviour of sand with initial static shear stress

This paper proposes a cyclic elasto-plastic model for simulating the undrained behavior of saturated sand with initial static shear (i.e., sloped ground) subjected to cyclic loading (i.e., earthquake). The model can describe both monotonic and cyclic torsional shear behaviors of saturated sand under drained and/or undrained conditions; moreover, it is capable of simulating qualitatively the stress-strain relationship and the effective stress path, even after the specimen achieves fully liquefied state. Its effectiveness is verified by simulating the results of undrained cyclic torsional shear tests on loose Toyoura sand specimens with initial static shear stress under stress-reversal and non-reversal loading conditions