液化后砂土流体特性测试装置的研发及试验研究

为研究液化砂土的流动变形特征，开展了液化砂土的流体特性试验研究。基于边界层理论研发一套液化砂土表观黏度测试装置，主要由调速电机、电机调速器、圆柱转子、扭矩传感器等部分组成，该装置能有效测试液化砂土的表观黏度；开展了不同孔压比、转速下饱和砂土表观黏度及圆柱转子所受摩擦力矩特性研究，着重分析了液化后砂土的表观黏度特性。结果表明，液化前孔压发展及液化后孔压消散阶段摩擦力矩均受到孔压比及转速的影响；液化后砂土孔压逐渐消散，强度恢复，流动能力衰减，表观黏度升高，表观黏度与孔压比呈现出一定的线性相关性；表观黏度随着剪应变率的增大而降低，且两者呈现出幂函数关系，表明液化后砂土具有典型幂律型剪切稀化非牛顿流体特征。

Apparatus development and experimental study for fluid characteristics of liquefied sand

To study the flow deformation characteristics of liquefied sand, the experiments on the fluid characteristics of liquefied sand were conducted. Based on the boundary layer theory, a test device for apparent viscosity of liquefied sand had been developed independently. The device, mainly composed of adjustable speed motor, motor speed regulator, cylindrical rotor, torque sensor and other components, can effectively measure the apparent viscosity of liquefied sand. The apparent viscosity of saturated sand, the friction torque of cylindrical rotor under different pore pressure ratios, and rotating speeds are studied, especially the apparent viscosity of liquefied sand. The results show that both in the pore pressure development before liquefaction and the pore pressure dissipation after liquefaction, the friction torque is affected by the pore pressure ratio and rotational speed. As the pore water pressure of liquefaction sand gradually dissipates, the strength recovers, and the flow capacity decreases as the apparent viscosity increases. There is a linear correlation between apparent viscosity and pore pressure ratio of the liquefaction sand. The apparent viscosity decreases as the shear strain rate increases. There is a power function relationship between the apparent viscosity and shear strain rate, showing that the liquefaction sand has the characteristics of typical power-law shear thinning non-Newtonian fluid.