大型水电站地下洞室稳定控制设计研究与实践

Research and practice on stability control design of large underground power station caverns

针对地下工程建设面临的地下洞室岩溶强发育、软岩分布范围广等突出工程地质问题,以水布垭、构皮滩、彭水等3个水电站地下工程为依托,系统开展了软硬相间地层、软岩及强岩溶等地质条件下大型地下洞室(群)关键技术问题研究。在设计实践中,提出了地下洞室扶壁岩锚复合式吊车梁结构型式“原岩隔墩支撑”结构技术、“超前置换封闭保压”的软岩处理技术、厂房纵轴线与岩层走向呈小交角甚至零度角布置的设计理念以及根据洞周围岩塑性区确定的“分界、分序、分层”的岩溶处理新技术。研究成果有效解决了复杂地质条件下大型地下洞室布置及围岩稳定问题,相关工程均已安全稳定运行,可为类似工程设计和稳定性评价提供一定的理论、方法及技术支撑。

In view of the main engineering geological problems faced by underground engineering construction,such as strong karst development of underground caverns and wide distribution of soft rocks,based on three underground hydropower station projects of Shuibuya,Goupitan and Pengshui,the key technical problems of soft-hard interlayer rock mass,soft rock and strong karst were systematically studied.We comprehensively put forward the buttress rock anchor composite crane beam of underground cavern,structural technology of original rock as division pier support,the soft rock treatment technology of advance replacement closed pressure retention,a design concept that the longitudinal axis of powerhouse and rock strata intersecting at a small angle or even zero-degree angle,and new karst treatment measures in way of reasonable boundary,order and layering.The research results had effectively solved the problems of large underground cavern layout and surrounding rock stability under complex geological conditions,and provided certain theoretical and technical support for similar engineering design and stability evaluation.