岩质边坡楔体稳定分析与临界滑面搜索

摘要

在楔体稳定分析中，滑动模式判断正确与否对楔体稳定性评价以及边坡开挖支护方案的选择具有重要意义。探讨Hoek-Bray方法在判断楔体破坏模式时存在的问题和产生错误的原因，并根据楔体破坏的运动学条件对Hoek-Bray方法进行修正，提出理论上较为完备的楔体稳定性计算方法。考虑到现场测量得到的不连续面的产状通常具有一定的离散性和分布范围，导致构成楔体的某一组或两组结构面并非完全确定。鉴于此，提出楔体稳定性的优化分析方法，采用遗传算法搜索具有最小安全系数的楔体及其临界滑面组成，为工程支护设计提供一个具有保守性优点的低限解答，确保边坡的稳定与安全。%In the stability analysis of rock wedge,judgment for sliding modes of the wedge is very important for stability assessment of rock slope and design of excavation and support schemes. This paper discusses the problem of sliding modes of the wedges and analyzes the causes of resulting in false sliding modes in Hoek-Bray method. An improved method for wedge stability analysis is proposed by employing the kinematical conditions for wedge failures to modify Hoek-Bray method. Considering the scatter in the dip and dip direction measurements,one set or two sets of discontinuities forming the wedges are not determined. This paper developed an optimal approach for undetermined wedge blocks,in which the genetic algorithm is used to locate the critical sliding surfaces and search for the wedge which has the minimum factor of safety. The method provides a lower bound solution with conservative advantage and the stability of rock slope can be assured.