【摘要】 土体在初始液化后仍然可能承受动荷载作用发生大变形。引入流体力学中的剪应变率和表观黏度的概念,对振动扭剪试验中饱和砂土液化后的流动特性进行了分析。分析中将砂土的状态分为0有效应力状态和非0有效应力状态。结果表明,砂土在0有效应力状态下表现出与静扭剪试验类似的"剪切稀化"非牛顿流体的特征,表观黏度随着剪应变率的增大而减小。加载周数对"剪切稀化"状态下的剪应变率幅值有影响,随着加载周数的增加,剪应变率幅值逐渐增大,而对流动曲线的形状没有影响。在非0有效应力状态下,砂土的表观黏度随应变的增大而增大,随孔压比的减小而增大,且所有的试验得到的表观黏度与孔压比具有一致关系。更多还原

【Abstract】 Large deformation may occur in the post initial liquefied sand undergone the dynamic loading.The definitions of shear strain rate and apparent viscosity in fluid mechanics are introduced to analyze the dynamic hollow torsional tests of post initial liquefied sand.There are two states in the post liquefied sand: zero effective stress state and non-zero effective stress state.The conclusions show that the sand characterized by shear-thinning non-Newtonian fluid in zero effective stress state which is similar to the static torsional tests.The loading cycle number does not have influence on the shape of flow curves under shear–thinning state except for the amplitude of shear strain rate,which increases with the increase of cycle number.Under non–zero effective stress state,the apparent viscosity increases with the increase of strain and the decrease of pore pressure.The apparent viscosity,which obtained from all tests,has a unitary formulation with the pore pressure ratio.更多还原