Modelling of drained and undrained cyclic Shear behavior of sand

Abstract

An elasto-plastic constitutive model capable of simulating both monotonic and cyclic drained and undrained torsional shear behavior of sand is presented. The generalized hyperbolic equation (GHE) has been employed to model the drained monotonic behavior of sand. Then the cyclic shear behavior is modelled by combining the GHE with extended Masing"s rules considering the hardening behavior of sand during drained cyclic loadings and the damage to soil skeleton at large stress levels. A modified stress-dilatancy relationship that relates the ratio of plastic strain increments (-dEPvoldyPzs)to stress ratio ("'zs/p') is proposed to simulate the volumetric behavior of sand. To model the undrained cyclic shear behavior, it is assumed that the total volumetric strain increment is equal to zero. The proposed model is calibrated by means of the results of a series of drained and undrained cyclic torsional shear tests on hollow cylindrical Toyoura sand specimens. Comparison with experiment data suggests that the propose model can reasonably simulate the stress-strain relationship and volumetric behavior of sand subjected to drained cyclic loadings and the generation of excess pore water pressure and stress-strain relationship during undrained cyclic loading.