考虑各向异性及循环效应的SIMSAND模型及应用

To study of the dynamic responses of sand under cyclic loading in the geotechnical engineering, including liquefaction, deformation accumulation and stiffness degradation, a constitutive model for simulating the effect of cyclic loading is first developed by introducing a shear strain reversal technology into the simple critical state sand model(SIMSAND). Then, the degradation of the strength during the simple shearing process is realized by incorporating the structural anisotropy of the granular material. Furthermore, the proposed cyclic model is verified by the triaxial cycle test and the simple shear cycle test on Fontainebleau sand. The enhanced model is implemented into finite element code ABAQUS for explicit dynamics analysis. Using the cyclic model pile test carried out by the French National Road and Bridge Laboratory(ENPC), finite element simulations are performed to study the dynamic response of piles under long-term cyclic loading. The results show that the enhanced cyclic SIMSAND model can reasonably predict the behavior of cyclic densification and strength degradation of the sand under pile-soil interaction.