考虑边坡内孔隙水压力效应的抗滑桩简化分析方法

Simplified analytical procedure of stabilizing piles against sliding considering pore water pressure

将塑性极限分析上限定理与抗剪强度折减技术相结合,建立了考虑孔隙水压力效应的抗滑桩加固土坡的极限平衡状态方程,采用数学优化方法求解桩侧极限有效土压力及相应的潜在破坏模式,其中水对边坡的影响作用通过虚功方程来体现,将孔隙水压力当作外力荷载做功,进一步地,基于获得的桩侧无量纲极限有效土压力,建立了抗滑桩的挠曲微分方程,采用有限差分法求解桩身的反应。在此基础上,针对典型算例边坡进行变动参数计算与对比分析,探讨了孔隙水压力对抗滑桩加固力与最优加固位置的影响。

Based on the upper-bound approach of limit analysis and the strength reduction technique, the equation for expressing the critical state of slope stabilized by a row of piles is formulated and is employed to determine the lateral limit effective earth pressure and its corresponding critical failure surface for a given slope subjected to pore water pressure. The presence of pore water can be embodied through work terms in the energy balance equation, and water pressure is considered as an external force similar to gravity and surface tractions. Furthermore, the governing equation of deflection for stabilizing pile is built based on the obtained dimensionless lateral limit effective earth pressure, and the numerical algorithm using finite-difference method is developed to numerically solve the partial differential equation. Finally, numerical computations are made to examine the effect of pore water pressure on optimum location of pile placement and the reinforced force supplied by piles with a typical example slope.