基于有限元极限分析的桩基础荷载下边坡稳定性

Study on Slope Stability under Loads Induced by Pile Foundations Based on Finite Element Limit Analysis

为探讨桩基础荷载作用下边坡稳定性变化的一般规律,提出相应的稳定性系数计算方法.首先,概述有限元极限分析方法,并引入某陡坡段桩基础工程实例,验证了该数值分析方法的合理性;其次,通过对桩顶水平荷载、黏聚力、桩坡相对位置等因素进行归一化处理,给出了不同工况时桩基础荷载下边坡稳定性系数计算方法,并将其以表格形式表示;然后,在探究桩基础荷载下边坡破坏模式的同时,引入荷载影响因子表征桩顶水平荷载对边坡稳定性系数的影响,并提出了桩基础荷载下边坡稳定性系数半理论半经验方法;最后,探讨了桩顶水平荷载、边坡坡比、内摩擦角、黏聚力及桩坡相对位置对边坡稳定性系数的影响.结果表明边坡稳定性系数与内摩擦角及黏聚力正相关,与桩顶水平荷载负相关.以上分析可为陡坡段桥梁工程设计提供参考,具有一定的理论及工程应用价值.

This paper aims to investigate the general law of slope stability under pile foundation-induced loads and propose a calculation method of corresponding stability coefficients.Firstly,the finite element limit analysis method is introduced and verified by the case for the pile foundation in sloping ground.Next,some factors(e.g.lateral load atop the pile,cohesion,and the relative position between pile and slope)are normalized,and the calculation method of stability coefficients of the slope subjected to pile foundation-induced loads under various conditions is presented and expressed in tabular form.Then,the load impact factor is presented to characterize the effect of lateral loads atop piles on slope stability factors,while slope failure modes are explored,and the semi-experiential and semi-theoretical method of slope stability coefficient under loads induced by pile foundations are presented.Finally,the effect of lateral loads atop piles,the slope inclination,internal friction angle of soils,cohesion,and pile position on slope stability factors are discussed.The results show that the slope stability factors are positively correlated with internal friction angle and cohesion,and negatively correlated with lateral loads atop the pile.These abovementioned analyses can provide references for bridge engineering design in the sloping ground,which are of certain theoretical and engineering application value.