基于极限分析下限方法的抗滑桩锚固深度检算

工程上一般采用通过控制滑动面以下锚固段桩周地层的强度来设计抗滑桩的锚固深度,即要求抗滑桩传递到滑动面以下地层的侧壁压应力不大于地层的侧向容许承载力。但其侧向容许承载力算式是基于传统Rankine土压力理论推导出的,仅适用于黏性土水平地面情况。为此,利用极限分析下限定理,考虑黏性土斜坡效应,建立了抗滑桩桩周土体侧向容许承载力的下限解法,通过数值计算以图表形式给出了综合主动和被动土压力系数数值,工程设计中直接以此进行抗滑桩桩周土体侧向容许承载力计算,进而利用弹性桩锚固深度公式确定抗滑桩的锚固深度。

Anchorage Depth Computation of Slope-stabilizing Piles Using Lower-bound Method of Limit Analysis

The principle of controlling stratum strength of anchorage portion around piles was generally involved in the design of anchorage depth of slope-stabilizing piles in practice.That is to say,the lateral stress acting on the surroundings below the sliding surface transferred from piles was required to be no larger than the lateral allowable bearing capacity supplied by stratum.However,the aforementioned lateral allowable bearing capacity was derived based on the conventional Rankine's soil pressure theory,and it may be only applied to the situation of horizontal ground.In this paper,the lower-bound approach based on limit analysis of plasticity was proposed to define the lateral allowable bearing capacity of soil around slope-stabilizing piles,where soil cohesion and inclination of slope were considered.Through numerical analyses,comprehensive active and passive earth pressure coefficient were given in a tabular form for different combination of the relevant parameters.The computed earth pressure coefficients could be directly adopted to assess lateral allowable bearing capacity of soil around stabilizing piles in engineering.Furthermore,the anchorage depth of piles could be accurately determined to offer an instructive guideline for the design of slope-stabilizing piles.