大型地下厂房洞室群运行期围岩支护结构安全分析与应用

Safety Analysis and Applied Research on Surrounding Rock Support Structure of Large-Scale Underground Powerhouse Cavern Group during Operation Period

摘要: 大型地下厂房洞室群在建成投运后，面临数十年甚至上百年的服役期，围岩–支护安全是确保其长期稳定运行的关键环节。本文首先分析了运行期地下厂房围岩支护结构安全分析的总体思路，认为应从围岩变形和支护结构的总体量值规律和异常数据两方面入手开展工作。对于异常数据，应进一步开展数值仿真和局部围岩稳定分析，实现洞室群在运行期的安全评价。最后，以某水电站右岸地下厂房洞室群为研究对象，基于运行期围岩变形及支护结构受力监测数据，结合数值模拟方法，系统分析了围岩长期稳定性及支护结构的安全状态。研究结果表明：主厂房围岩变形主要集中于施工期，运行期变形量值总体较小，蓄水运行后，围岩增量变形有限，表明拱坝蓄水对围岩影响有限。针对局部锚索测力计持续增长现象，通过地质条件分析与块体稳定性复核，确认块体安全系数满足安全要求。研究为运行期地下厂房围岩–支护体系的安全评价提供了数据支撑与理论依据，弥补了既有研究对运行期长期稳定性分析的不足。

Abstract: After a large-scale underground powerhouse cavern group is completed and put into operation, it will face a service period of several decades or even hundreds of years. The safety of the surrounding rock and support is a crucial link to ensure its long-term stable operation. Firstly, this paper analyzes the overall idea of the safety analysis of the surrounding rock support structure of the underground powerhouse during the operation period, and believes that the work should be carried out from two aspects: the overall magnitude laws of the surrounding rock deformation and the support structure, as well as the abnormal data. For the abnormal data, numerical simulation and local surrounding rock stability analysis should be further carried out to achieve the safety evaluation of the cavern group during the operation period. Finally, taking the cavern group of the underground powerhouse on the right bank of a certain hydropower station as the research object, based on the monitoring data of the surrounding rock deformation and the force of the support structure during the operation period, combined with the numerical simulation method, the long-term stability of the surrounding rock and the safety state of the support structure are systematically analyzed. The research results show that: the deformation of the surrounding rock of the main powerhouse is mainly concentrated in the construction period, and the deformation magnitude during the operation period is generally small. After the impoundment and operation, the incremental deformation of the surrounding rock is limited, indicating that the impoundment of the arch dam has a limited impact on the surrounding rock. In response to the continuous growth phenomenon of the local anchor cable dynamometer, through the analysis of the geological conditions and the review of the block stability, it is confirmed that the safety coefficient of the block meets the safety requirements. This research provides data support and theoretical basis for the safety evaluation of the surrounding rock-support system of the underground powerhouse during the operation period, and makes up for the deficiencies of the existing research on the long-term stability analysis during the operation period.