向家坝水电站大型地下厂房洞室群施工和监测

CONSTRUCTION AND MONITORING STUDY OF LARGE UNDERGROUND POWERHOUSE CAVERNS OF XIANGJIABA HYDROPOWER STATION

金沙江向家坝水电站地下厂房规模庞大,具有结构尺寸大、地质条件复杂、支护工程量大、施工干扰大等特点。通过大量的科研设计,确定地下洞室群尤其是主厂房的施工程序和支护参数。在施工过程中采用精细化管理对施工进行严格控制,建立设计、科研、施工一体化的实时监测动态分析反馈系统。开挖结束后,主厂房围岩变形趋于稳定,顶拱最大变形13.36 mm,边墙最大变形6.74 mm,均小于设计计算值(顶拱最大位移20.4 mm、边墙最大位移62.5 mm),并小于国内同类工程。总结向家坝水电站大型地下厂房洞室群施工实践中形成的设计、施工和项目管理原则和程序,对类似工程具有指导和借鉴作用。

The underground powerhouse in Xiangjiaba Hydropower Station has a huge scale,with the characteristics of complex structure,complicated geologic condition,large support quantities and big construction disturbance.Based on a large number of studies,the construction procedures and supporting parameters for underground caverns,especially the main powerhouse,are determined.The strict managements and controls are adopted in the construction;and a real-time monitoring and dynamic analysis system which integrates design,research and construction is established.The measured displacements in the rock masses of underground powerhouse are small and develop stably after excavation,with the maximum magnitudes of 13.36 mm in roof and 6.74 mm in walls,which are smaller than the design values of 20.4 mm in roof and 62.5 mm in walls;and they are smaller than ones of similar underground powerhouse.The principles and procedures of design,construction and management in construction of the Xiangjiaba underground powerhouse complex are summarized,so as to provide some references for the similar large underground powerhouse projects.