Analysis of seepage failure of deep foundation pit in silty sand

In the area of sandy and silty soil,seepage failure is the main factor that threatens the safety of deep foundation pit and surrounding environment. Combined with numerical simulation,model experiments were performed to explore the influence of dense,cohesive strength,internal friction angle,friction behaviour and scale on the seepage phenomena of deep foundation pit in uniform sandy and silty soil. The results show that the critical hydraulic gradient not only depends on the density of soil,but also related to soil category,strength index,roughness of pile face and deepth of retaining structure. Those results can be useful.