关键词: 三轴循环加卸载, 高含冰量冻结砂土, 围压, 含水率, 能量耗散, 剪切模量

Abstract: Energy dissipation and shear modulus variation of ice-rich frozen silty sand with different water contents are investigated in a comprehensive experimental program of triaxial loading-unloading cyclic tests under various confining pressures at the same temperature and strain rate conditions. The results show that the plasticity of frozen silty sand firstly increases and then decreases as the water content increases. The frozen soil presents mostly plastic failure mode with a water content threshold of 30.6%. The energy dissipation as shear strain increases is mainly induced by deviator stress variation, and less energy dissipation overcomes the effect between ice particles in the deformation process of frozen soil. Shear modulus always decreases as shear strain increases. The decreasing rate of shear modulus has an apparent change point at low water content.. Three types of effects of water content on shear modulus can be observed. These testing results can provide important implications for the parameter selection on engineering design in permafrost region with ice-rich soil.

Key words: triaxial loading-unloading cycle, ice-rich frozen silty sand, confining pressure, water content, energy dissipation, shear modulus