基于区间理论与GSI的岩质边坡稳定可靠性分析方法

摘要

针对采用结构面表面特征与岩体结构的定性描述确定岩体地质强度指标GSI存在较强主观性的特点,首先以结构面表面等级SCR与岩体结构等级SR对其进行量化处理,并根据组成SCR与SR的量化指标取值过程中所具有的不确定性,采用区间值表示参数取值,建立岩体量化GSI区间值确定方法;其次,根据Hoek-Brown准则等效岩体抗剪强度参数转换关系,采用区间数学理论建立出岩体力学参数区间值确定方法;然后,通过区间组合法求解岩质边坡安全系数区间值,并在确定安全系数要求值的基础上采用非概率可靠性分析方法进行稳定可靠性评价,进而建立出基于区间理论与GSI的岩质边坡稳定可靠性分析方法;最后,将其应用于分析湖南省柘溪水电站进水口高边坡稳定性,结果表明该方法具有一定的合理性与可行性.在缺乏现场岩体力学试验与大量样本数据的情况下,该方法为岩质边坡从岩体力学参数确定到稳定可靠性评价提供了一条新途径.%It is somewhat subjective when determining the geological strength index ( GSI) through qualitative description of the surface condition and structure of rock mass. Surface condition rating ( SCR) and surface rating ( SR) are employed to quantify the values of the surface condition and structure using interval values, to reflect the uncertainty of the values of SCR and SR. A method to determine the GSI interval values with quantitative indexes is presented, and a method to determine the mechanical parameters of rock mass with interval values is proposed. There is a conversion relationship of the rock mass shear strength parameters with the Hoek-Brown strength criterion. A interval interconnection method is employed to solve the interval safety factors of rock slopes. A non-probabilistic reliability analysis method is employed to evaluate the stability reliability using the required safety factor. A reliability analysis method for rock slope stability with interval theory and GSI is proposed. The proposed method is applied to analyze the stability of the water-inlet high rock slope of the Zhexi hydropower station in Hunan province.