考虑坡体后缘张拉应力折减的超载边坡稳定性分析

Stability Analysis of Overloaded Slope Considering Tensile Strength Cut-off at the Trailing Edge

为考虑后缘张拉应力对超载边坡稳定性的影响,本文基于极限分析上限法对土体抗拉强度的折减进行推导分析。计算时结合随机搜索法、二次优化法进行算法上的优化,计算不同坡角、内摩擦角、超载系数、地震荷载以及张拉折减系数下边坡的稳定性。研究结果表明,考虑抗拉强度的折减对于边坡临界加速度影响显著,而随着超载作用的不断增加,边坡临界加速度产生剧烈折减;考虑张拉强度折减后超载边坡的永久位移可超过传统分析法的2倍以上,当抗拉强度折减程度不断增加,超载边坡位移累计速度随之迅速增加。因此考虑土体抗拉强度折减的影响对超载边坡的抗震稳定性设计至关重要。

In order to consider the influence of trailing edge tensile stress on the stability of overloaded slope,this paper deduces and analyzes the reduction of soil tensile strength based on the upper bound method of limit analysis,and optimizes the algorithm by combining random search method and quadratic optimization method.The stability of slope under different slope angle,internal friction angle,overloaded coefficient,seismic load and tension reduction coefficient is calculated.The results show that considering the reduction of tensile strength has a significant effect on the critical acceleration of slope,and with the continuous increase of overloading,the critical acceleration of slope has a sharp reduction;after considering the reduction of tensile strength,the permanent displacement of overloaded slope can be more than 2 times of that of traditional analysis,and the cumulative displacement velocity of overloaded slope increases rapidly with the continuous increase of tensile strength reduction.Therefore,considering the influence of soil tensile strength reduction is very important for the seismic stability design of overloaded slope.