基于塑性变形理论的圆形抗滑桩边坡稳定性分析

圆形截面抗滑桩广泛应用于边坡加固和地质灾害治理工程中,传统的圆形截面抗滑桩理论和经验计算公式未考虑土-拱效应,因此计算结果不合理。本文基于Ito塑性变形理论,考虑桩-土相互作用的土-拱效应,推导出圆形截面抗滑桩在考虑土-拱效应时计入桩土摩擦力的水平分布力计算公式以及边坡稳定性系数Fs;并结合工程算例,讨论了土体重度、黏聚力、内摩擦角和桩间距对边坡稳定性的影响,研究结果表明:(1)通过推导的水平分布力公式,可得圆形截面抗滑桩的布桩位置对桩身抗力和边坡稳定性系数的影响,边坡稳定性系数在抗滑桩距离坡脚约为0.5L时最大,0.4~0.6L时处于稳定状态;(2)黏聚力和内摩擦角对边坡稳定性起着决定性的影响因素,土体的重度对边坡稳定性的影响并不明显,当桩身距离坡脚>0.5L时,边坡土体的重度对边坡稳定性影响更加明显;(3)在考虑边坡稳定性和工程造价的条件下,采取2~2.5倍桩径距离进行布桩可以达到良好的工程效果。

Stability Analysis of Circular Slide-resistant Pile Slope Based on Plastic Deformation Theory

Anti-slide pile with circular cross section is widely used in slope reinforcement and geological disaster control engineering.The soil-arch effect is not considered in traditional theory and empirical formula of anti-slide pile with circular cross section,so the calculation results are unreasonable.Relying on Ito plastic deformation theory and considering the soil arching effect of pile-soil interaction,this paper deduced the calculation formula of horizontal distribution force of pile-soil friction in consideration with the soil arching effect of anti-slide pile with circular cross section and the slop stability coefficient Fs, and discussed influence of the soil density,cohesion,internal friction angle and pile spacing on slope stability in combination with the engineering example.The research results show as follows:(1)by deducing the formula of the horizontally distributed forces,it can be concluded that the influence of pile location of anti-slide pile with circular cross section on pile resistance and slope stability coefficient,the slope stability coefficient is the maximum when the distance between the slope anti-slide pile and the slope toe is about 0.5L,0.4-0.6L in a stable state.(2)The cohesion and internal friction angle play a decisive role in the stability of the slope,and the influence of soil mass on the stability of the slope is not obvious.When the pile body is away from the foot of the slope>0.5L,the influence of soil mass on the stability of the slope is increased.(3)Considering the stability of slope and engineering cost,pile spacing of 2~2.5 d(pile diameter)can achieve good engineering effect.