软硬互层反倾岩质边坡稳定性影响因素分析及破坏模式研究

STUDY ON INFLUENCE FACTORS OF STABILITY AND FAILURE MODES OF ANTI-DIP ROCK SLOPE WITH SOFT AND HARD INTERBED

反倾边坡破坏会诱发严重的地质灾害,因此对软硬互层反倾岩质边坡的稳定性及破坏模式进行研究具有重要的意义。本文基于数值模拟的方法,利用离散元UDEC软件,首先基于正交试验设计法,考虑了边坡坡角、岩层倾角、坡高、相邻软硬岩层总厚度、硬软岩层厚度比、硬软岩层力学参数序号比、结构面力学参数7个因素的影响,设计了32组正交试验,利用强度折减法对边坡的稳定性及可能的破坏模式进行模拟,并从边坡稳定系数和位移两个方面对计算结果进行敏感性分析。结果表明,边坡坡角和岩层倾角对稳定系数影响较大,结构面力学参数和坡高对边坡位移影响较大;然后对边坡的破坏模式进行归纳总结,将软硬互层反倾边坡的破坏模式分为弯曲倾倒破坏、坍塌滑动破坏和块体倾倒破坏3种类型,并对每种破坏类型的边坡特征进行详细分析。

The failure of anti-dip slopes can induce serious geological disasters,so it is of great significance to study the stability and failure modes of anti-dip rock slopes with soft and hard interbed.This paper is based on numerical simulation method and uses discrete element software UDEC.Firstly,this paper takes into account the influence of the slope angle,rock inclination angle,slope height,total thickness of adjacent soft and hard rock layers,thickness ratio of hard and soft rock layers,ratio of mechanical parameter number of hard and soft rock layers,and the mechanical parameters of structural plane.Then based on orthogonal experimental design method,this paper designs 32 sets of orthogonal tests to simulate the stability of the slope and possible failure modes by the strength reduction method.The sensitivity analysis is conducted from two aspects of slope safety factor and displacement.It is found that the slope angle and rock inclination angle have a great impact on the safety factor,and the mechanical parameters of structural plane and slope height have a great impact on the slope displacement.Then the failure modes of anti-dip rock slope with soft and hard interbed are summarized and divided into three types:bending-dumping,collapse-sliding and block-dumping failures.The characteristics of each failure modes are analysed in detail.