Simulation and Amelioration of Wu-Bauer Hypoplastic Constitutive Model under Dynamic Load

摘要

The stress-strain relation of sand can be modeled with Wu-Bauer hypoplastic constitutive model, in which the magnitude and direction of stress increment depend on not only the previous stress state, but also the magnitude and direction of current strain increment. The parameters of this model can be determined conveniently by simple triaxial test. Under static load Wu-Bauer hypoplastic constitutive model can well simulate strength and deformation of sand. But under dynamic load, the major shortcoming-ratcheting is produced in Wu-Bauer hypoplastic constitutive model. For eliminating ratcheting, Wu-Bauer hypoplastic model is ameliorated based on intergranular strain tensor. The new parameters in ameliorated model are determined by mode search method. Under cyclic load of oedometric compression and undrained dynamic triaxial, the mechanics features of sand are described by the ameliorated Wu-Bauer hypoplastic constitutive model. Preliminary result shows that stress-strain relation of sand under dynamic load can be well considered and ratcheting may be removed in the ameliorated Wu-Bauer hypoplastic constitutive model.