Effect of consolidation ratio on high relative density silt under cyclic principal stress rotation

摘要

The remolded Yangtze River silt with the relative density of 70% were tested by hollow cylinder apparatus. The samples were consolidated with different consolidation ratio (Ac) of 1 and 2, and then underwent cyclic principal stress rotation. It was found that for the samples of Kc=1, the failure was featured by the pore water pressure reaching initial effective spherical stress. With the increase of shear stress, the pore water pressure changed from two-phase-transformation-point mode into singlephase-transformation-point mode. As to the deviator strain, it showed brittle failure characteristics and was limited within 0.5% at the collapse points. The collapse of strain occurred basically simultaneously with the cataclysmic phase transformation point of pore water pressure. As for the samples of Kc=2, the deviator strain generated at a relatively high speed from the start of loading. However, because the pore water pressure ratio was rather low and kept at a stable value of about 0.45 finally, the strain could generate smoothly to a larger extent. Accordingly the samples of Kc=2 had much higher dynamic strength than the ones of Kc=1.