Abstract:In order to explore the piping mechanism and the mechanical properties after piping of soils with different fine particle content, three kinds of soils with different fine particle content were selected and piping up was simulated by self-developed piping triaxial apparatus. Through piping test and drainage shear test after piping, the effects of fine particle content on critical hydraulic gradient, cumulative sand inflow, peak strength and volume change were analyzed. The results show that the critical hydraulic gradient and critical flow velocity increase with the increase of fine particle content before piping. The growth rate of cumulative sand inflow decreases with time under the action of higher hydraulic gradient. The cumulative time of sand gushing decreases with the increase of fine particle content when the same fine particle content is lost. With the increase of fine particle content, the peak strength of soil changes irregularly after piping, the volume of soil first shears and then dilates, and the maximum volume shrinkage of sample increases with the increase of fine particle content.