水平成层土坡破坏机理及稳定性分析

Analysis of stability and failure mechanism of horizontal stratified soil slope

采用室内模型试验及极限分析上限法对水平成层土坡破坏机理与稳定性进行研究。首先,构建室内模型分别模拟不同边坡高度与不同分层厚度条件下的水平成层土质边坡,分析在坡顶条形荷载作用下坡顶与坡面位移-荷载变化规律、极限承载力及破坏面形态和位置。基于极限分析上限法基本原理,针对水平成层土质边坡圆弧+直线的破坏模式建立机动容许速度场,推导该类边坡在坡顶条形荷载作用下极限承载力的求解公式,并将室内试验结果与数值分析结果进行对比分析。研究结果表明:水平成层土质边坡在坡顶条形荷载作用下的破坏模式为圆弧+直线组合式,其滑动面由凹向边坡体内部的圆弧曲面和平面2部分组成,圆弧曲面上端位于加载梁后缘处,下端处于填土分层处,平面为填土分层交界面;上限法在求解水平成层土质边坡稳定性问题上具有一定的合理性。

Model testing was conducted to study the failure mechanism of the horizontal stratified soil slopes using upper bound theory of limit analysis. The variation law among the displacement and load, ultimate bearing capacity and the shape and position of sliding surface of the horizontal stratified soil slopes were simulated with different layer thicknesses and different heights of fill under the same strip load on the upper surface of the slope. Based on the principle of upper bound theory of limit analysis, the velocity fields of the failure mode with the arc-straight line sliding surface which was obtained from model test were established. The formula was deduced for calculating the ultimate bearing capacity of slope with strip load on the top. The results show that the sliding surface consists of the circular arc surface with the inwards slope and plain surface. The top of circular arc surface is located at the back of loaded beam and bottom is in the edge of filling layers, and plain surface is the interface of filling layer. The upper bound theory of limit analysis can be used to solve the stability problem of the horizontal stratified soil slopes.