对软岩陡坡椅式桩（CSP）支挡结构，通过大比例模型试验研究路基面分级荷载作用下其内力变形规律、结构-岩土体相互作用，根据试验条件和结构受力状态，提出了其设计计算方法。结果表明，椅式桩的空间结构特性可有效控制结构变形和减小桩身内力；主副桩桩身弯矩大小接近，最大弯矩位于坡面处，桩侧岩石压力主要跟桩基变形与岩石变形模量有关；椅式桩一般不会出现结构倾倒破坏，软岩边坡则以浅层破坏为主；基于弹性地基梁的分析解，可较好地描述椅式桩的内力变化及其分布规律。研究结果对正确分析椅式桩支挡结构的抗滑机制和设计计算具有较好的参考价值。

The stress-deformation law and the structure-soil interaction of chair-shaped pile(CSP) retaining structure on soft-rock steep slope under stepwise loading on the subgrade surface are studied by large-scale model test. According to the experimental conditions and stress states, the design and calculation method of CSP are proposed. The test results show that the spatial structure properties of CSP can efficiently control the deformation and reduce the pile stress; the bending moments of main and side piles have little differences; the maximum bending moment is located at the slope surface; and the pressure of pile side rock is related to the deformation of piles and the deformation modulus of rock. The toppling failure of CSP would not occur generally; and the shallow layer failure is the main failure of soft-rock slope. Based on the analytical solution of elastic foundation beam, the change and distribution rules of internal forces of CSP could be described well. The study results have a good reference value to correctly analyze the anti-slide mechanism, design and calculation of CSP retaining structure.