大岗山水电站地下厂房洞室群围岩开挖损伤区研究

RESEARCH ON EXCAVATION DAMAGE ZONE OF UNDERGROUND POWERHOUSE OF DAGANGSHAN HYDROPOWER STATION

以大岗山水电站地下厂房洞室为研究对象,通过施工阶段的围岩力学性状测试、开挖变形长期监测研究地下洞室开挖损伤区的分布范围和损伤劣化特征。以围岩变形和损伤区实测成果为基础,建立基于正交设计–支持向量机–粒子群算法的反演分析方法。通过对地下厂房洞室开挖损伤区的测试与监测、反演分析表明,损伤区分布范围约为临空面向岩体内部3～7 m范围,其中,围岩类别不同,其损伤区分布范围不同,损伤劣化程度也不同,具体表现为围岩质量越好,其损伤范围越小,但是损伤区岩体损伤劣化程度越高。相关认识是初步的,对类似重大工程的设计施工有一定的参考价值,但还需要进一步开展理论与工程实践研究。

Taking underground powerhouse of Dagangshan hydropower station as the research object,distribution range and damage deteriorating characteristics of excavation damage zone（EDZ） of underground chambers are studied through mechanical properties testing and long-term monitoring of the surrounding rock mass at construction stage.Based on measured displacements and observed EDZ,a method of back analysis is established by using the orthogonal design,support vector machine and particle swarm optimization.By testing,monitoring and back analysis of the EDZ,it？s found that the EDZ scope is within a range of 3–7 m;and different surrounding rock classes have different EDZ distribution ranges and different damage deterioration degrees.The results show that the better quality of surrounding rock mass is,the smaller scope of the EDZ is,and the higher damage deterioration degree of the EDZ is.The study which needs further theoretical and application research is preliminary;and it has certain reference value for design and construction of similar major projects.