Laboratory Tests on Flow Characteristics of Pre-Liquefied Sand

Liquefied and post-liquefied sand can be treated as a kind of fluid. Previous research has suggested that liquefied or post-liquefied sand is a shear-thinning, non-Newtonian fluid. The flow characteristics of pre-liquefied sand under high pore pressure ratio are worth discussing. According to the theory of dropping ball viscosimeter, the test apparatus of flow characteristics of pre-liquefied sand is developed. The saturated sand was put in a model box. A water tank was linked with the bottom of the sand box. The height of the water tank can be lifted to provide the excess pore pressure required in the sand soil. A steel sphere, embedded in the sand box, can move in the horizontal direction under a dragging force. Resistance and ball velocity were measured during dragging and, meanwhile, apparent viscosity is evaluated. The velocity of the sphere and excess pore pressure ratio were the main focuses in the tests. The results suggest that the apparent viscosity of the pre-liquefied sand decreases with the growth of the strain rate. The pre-liquefied sand is shear thinning, non-Newtonian fluid which is similar with liquefied and post-liquefied sand. The apparent viscosity of the pre-liquefied sand also decreases with the growth of the excess pore pressure ratio.