基于Hoek-Brown强度准则的地下洞室开挖可靠度分析

Reliability Analysis of Underground Cavern Excavation Based on the Hoek-Brown Strength Criterion

地下洞室可靠度分析在地下空间开发工程中具有重要意义。采用拉丁超立方抽样法对工程实测获得的结构面特征指标进行抽样,将样本数据代入地质强度指标GSI评价体系中获得GSI概率分布函数,然后基于Hoek-Brown经验强度准则计算获得围岩力学参数的概率分布函数,进而利用数值模拟获得地下洞室变形量的概率分布函数,并结合洞室开挖的最大允许位移将求解可靠度指标转化为求解超过最大允许位移的概率。以五岳抽水蓄能电站为例,计算了主厂房不同部位的位移超过最大允许位移的概率,对主厂房的稳定性进行了评价。评价结果与工程实际情况基本相符,说明本文提出的方法可有效用于地下工程的开挖可靠度分析.

The reliability analysis of underground caverns is of great significance in underground space development projects.The Latin hypercube sampling method was used to sample the structural surface characteristic indicators obtained from engineering measurements.The sample data was then substituted into the geological strength index GSI evaluation system to obtain the GSI probability distribution function.Based on the Hoek-Brown empirical strength criterion,the probability distribution function of the surrounding rock mechanics parameters was calculated.Then,the probability distribution function of the deformation of the underground cavern was obtained through numerical simulation.Combined with the maximum allowable displacement of the cavern excavation,the reliability index was solved by converting it into the probability of exceeding the maximum allowable displacement.Taken the Wuyue pumped storage power station as an example,the probability of displacement exceeding the maximum allowable displacement in different parts of the main building was calculated,and the stability of the main building was evaluated.The evaluation results are basically consistent with the actual situation of the project,indicating that the method proposed in this article can be effectively used for the reliability analysis of excavation in underground engineering.