深切河谷岸坡层状岩体倾倒变形演化过程及机理分析

Evolution Process and Mechanism Analysis of Toppling Deformation of Layered Rock Mass on Bank Slope of Deep Incised Valley

深切河谷岸坡的层状岩体在河流长期的侵蚀作用下,会产生大量的倾倒变形破坏,给工程建设造成极大的困扰.以黑河库区和镇安县倾倒变形边坡为例,使用DDA模拟了河流侵蚀作用下边坡的倾倒变形过程,探究了深切河谷岸坡岩体倾倒变形的演化过程和机理,取得如下成果:(1)揭示了黑河库区和镇安县边坡发生倾倒变形的主要原因;(2)对河流侵蚀作用下中厚层和薄层岩体边坡倾倒变形过程进行划分,薄层岩体边坡倾倒变形过程中会出现爬坡效应;(3)坡脚的结构面强度变大,坡顶应力释放导致的主应力方向发生偏转是边坡发生倾倒变形的根本原因,倾倒变形的模式则是由剪应力分布情况决定的;(4)对中厚层岩体倾倒变形边坡进行锚索支护模拟,相较于预测工况,计算后边坡各处的位移明显减少,从坡顶到坡脚施加的锚索的锚固力逐渐减小.

Under the long-term erosion of the river,the layered rock mass on the bank slope of deep incised valley will produce a large number of toppling deformation and damage,which has caused great trouble to the engineering construction. In this paper,taking Heihe Reservoir and Zhen’an County as examples,DDA is used to simulate the process of slope toppling deformation under river erosion,and the evolution process and mechanism of toppling deformation of rock mass on the bank slope of deep incised valley are explored. The following achievements have been made:(1)The main causes of slope collapse deformation in Heihe Reservoir and Zhen’an County have been revealed.(2)The toppling deformation process of medium-thick rock slope and thin rock slope under river erosion is divided. The climbing effect will appear in the toppling deformation process of thin rock slope.(3) The increase of the strength of the structural plane at the foot of the slope,and the deflection of the principal stress direction caused by the stress release at the top of the slope is the root cause of the slope toppling deformation,and the mode of toppling deformation is determined by the distribution of shear stress.(4)Compared with the predicted working conditions,the displacement of the slope after calculation is significantly reduced,and the anchoring force of the anchor cable applied from the foot of the slope to the foot of the slope is gradually reduced.