Abstract：Soil nailing is a widely used means for slope stabilization in the last two decades. The traditional limit equilibrium method in the design of soil-nailed systems can not give the maximum depth Hu for soil-nailed retaining structure and excavation depth Dhi of each step. Based on energy method and power equilibrium equation，the formula of limit excavation depth of soil-nailed retaining structure is presented，and a new safety factor ki of each step and Dhi of each step are also established. Pseudo cohesion DC is obtained by taking the effect of reinforcement and restriction soil nail as the increasing soil cohesion. The main influence factors of soils and soil nails and the variation rules of limit excavation are analyzed. All these can be used for references to the design of soil-nailed retaining structures.
