考虑空间变异性的抗滑桩三维边坡上限研究

准确的加桩边坡稳定分析是进行合理抗滑桩设计的重要保证, 而传统的对数螺旋线机构的极限分析方法不能反映土体力学性质的内在不确定性和空间变异性, 针对上述问题, 文章提出一种新的基于离散化运动上限分析的三维机构, 采用空间离散化的思路, 将加桩边坡滑动面分解为若干三角形的离散单元, 以适应边坡内部不同位置处内摩擦角变异对机动许可条件的要求, 桩土相互作用简化为三角形分布的侧向阻力, 在此基础上推导了该机构的外力功率与内能耗散, 并提出了安全系数的计算流程。通过验证证明了该机构计算结果的正确性, 结合稀疏多项式混沌展开, 初步讨论了空间变异对加桩边坡可靠性的影响。

Accurate stability analysis of pile-supported slopes is an important guarantee for reasonable anti-slide pile design. However, the traditional limit analysis method of the logarithmic spiral mechanism cannot reflect the inherent uncertainty and spatial variability of soil mechanical properties. To address this issue, this paper proposes a new three-dimensional mechanism based on the upper limit analysis with spatial discretization. The mechanism adopts the idea of spatial discretization and decomposes the sliding surface of the pile-supported slope into several discrete units of triangles to adapt to the requirement of maneuverability conditions for different locations of internal friction angle variation within the slope. The pile-soil interaction is simplified to the lateral resistance of the triangle distribution. Based on this, the external power and internal energy dissipation of the mechanism are derived, and the calculation process of the safety factor is proposed. The correctness of the calculation results of this mechanism is verified. Combining with sparse polynomial chaos expansion, the influence of spatial variability on the reliability of pile-supported slopes is preliminarily discussed.