主应力轴旋转下小偏压固结密实粉土崩塌特性及孔压模型研究

In order to study the properties of anisotropically consolidated silt subjected undrained cyclic principal stress rotation(CPSR),series of tests were performed. The tested hollow cylinder silt samples had the initial relative density of 70% and were consolidated with different consolidation ratio(Kc) before CPSR.The results showed that for the samples with Kc ≤1.5,they collapsed at low or medium strain and liquefied, but when Kc > 1.5, the samples' strain increases stably and the pore water pressure developed into dynamic equilibrium states. And the peak values of pore pressure in dynamic equilibrium states were lower than those in the liquefaction failure states. On the other hand, differing from the isotropically consolidated samples,the samples with Kc between 1.1 and 1.5 had the maximum pore water pressure at liquefaction lower than the initial effecive spherical stress. Further more they decreased with the increase of Kc, but barely dependent of dynamic shear stress. So did the pore water pressure at collapse states. The collapse cycles of anisotropically consolidated samples were larger than that of the isotropically consolidated ones with the same shear stress level. But there were no monotonic relationship between collapse cycles and Kc. Finally a model of pore water pressure development for the anisotropically consolidated silt under CPSR was put forward, which could reflected the collapse characteristics as well as the effects of consolidation ratio and dynamic shear stress level.