A simplified method to analyze the load on composite retaining structures based on a novel soil arch model

Soil arch effect has been widely used in the determination of pile spacing, whereas its application on the design of composite retaining structures to stabilize potentially unstable slopes is still rare. As a typical composite retaining structure, stabilizing piles combined retaining wall could effectively avoid slope failure, while the problem of evaluating the load distribution between stabilizing piles and retaining wall based on soil arch effect remains to be solved. In this paper, a novel soil arch model is proposed and used aiming to theoretically analyze the soil arch effect on the load against stabilizing piles and retaining wall. The results show that the load acting on stabilizing piles should be the residual sliding force derived from rear soil mass, and the load against retaining wall should be the maximum value between the Coulomb’s active earth pressure derived from sliding wedge before soil arch and the residual sliding force produced by front soil mass. Then, on this basis, a simplified method for calculating the load on stabilizing piles and retaining wall respectively considering the soil arch effect is put forward. A railway cutting slope reinforced with stabilizing piles combined with retaining wall is taken as an application case, and the simplified method is adopted to quantitatively analyze the soil arch effect on the load distribution between stabilizing piles and retaining wall. The conclusion of this paper would provide useful help toward the process of safer and more economical design of composite retaining structures in slope engineering harness.