地震作用下矿山边坡永久位移非线性分析

地震作用下矿山边坡的稳定性一直是热点话题,而岩土体非线性强度特征对边坡安全影响更为显著。本文以不同破坏条件下的矿山边坡为研究对象,考虑岩体后缘抗拉强度折减的作用,选取极限分析法中平面应变的对数螺旋旋转机制构建屈服加速度的功能方程,以计算不同坡角、内摩擦角、顶部荷载强度、地震荷载以及张拉折减系数下的矿山边坡的稳定性;采用经典Newmark法对贺州市某矿山项目中典型矿山边坡位移进行推导计算。研究结果表明:考虑非线性破坏对于边坡屈服加速度的影响显著,而顶部荷载加剧屈服加速度的折减;考虑后缘张拉强度折减后矿山边坡的位移可达到传统分析的近2倍。因此,考虑岩土体抗拉强度折减的影响对矿山边坡的抗震稳定性设计至关重要。

Nonlinear analysis of mine slope permanent displacement under seismic actions

The stability of mine slopes under earthquake has always been a hot topic, while the nonlinear strength of rock and soil have a more significant impact on slope safety. In this paper, the stability of mine slopes under different failure conditions were studied with the influence of tension cut-off. The plane strain logarithmic spiral rotation mechanism of limit analysis was selected to derive the work equation of yield acceleration under various combination of slope angle, frictional angle, overload coefficient, seismic load and tension cut-off factor. The classical Newmark method was used to derive and calculate the displacement of a typical mine slope in a mining project in He Zhou. Results show thatthe tension cut-off has huge influence on yield acceleration of slope while the overload would cause greater reduction of the yield acceleration. On the other hand, the permanent displacement of mine slope considering tension cut-off would be 2 times of its counterpart without considering tension cut-off. As a result, the consideration of tension cut-off is critical to the seismic stability design of mine slope.