Abstract：The model test for simulating effect of suspended cut-off wall on preventing seepage failure in two-layer foundation of levee has been carried out in a sandbox. The experimental results for different suspension depths have been obtained. The results indicate that the suspended cut-off wall has significant effects on the prevention of seepage failure as well as reduction of seepage quantity in two-layer foundation of levee which is composed of upper clay and lower silt soil during the stability seepage. For the two-layer foundation of levee，sand spring occurs at the weak positions，then contact erosion occurs at the interface of silt clay and silt. When the water level rises continuously and exceeds the critical water level，the seepage channel develops from downstream to upstream，and runs through the whole soil. At this time，the seepage failure occurs. Research indicates that，under the function of suspended cut-off wall，the condition that seepage failure occurs has been improved，for example，the water level rises greatly，critical apparent hydraulic gradient increases obviously，the seepage quantity reduces distinctly，and the pore water pressure changes evidently. The results show that the suspended cut-off wall can prevent the seepage failure effectively，at the same time，it is constructed easily and acceptable in economy，so it is worth applying in project.
