Abstract: In the design of the deep excavation support, the bored cast-in-place reinforced concrete piles with slope are frequently used to facilitate the construction schedule and to reduce project cost. Different from the natural soil slope, the process of the foundation excavation is the removal of the existing soil, and there is a stress release process. The stability is lower than the corresponding natural soil slope with similar slope angle. At the same time, the displacement of the pile head also has a negative impact on the stability of the slope above the pile. The finite element software ABAQUS was used to simulate the stress release process during excavation. The slope stability was investigated by adjusting the bending stiffness EI of the support pile and by using the strength reduction method. The analytical results show that the stability of the slope above the pile head is proportional to the stiffness of the supporting soldier pile and the lateral deflection of the pile head.

Key words: Factor of Safety, Slope Instability, Bending Stiffness, Stress Release