大发水电站地下厂房支护设计

Design for Underground Powerhouse Support at Dafa Hydropower Station

大发水电站位于大渡河中游右岸的一级支流田湾河上,地下厂房工程区紧邻具备发生强震可能的磨西断裂,工程场地地震基本烈度厂区为Ⅸ度,地质构造复杂。在顶拱开挖后,揭示出f1断层及其他4组裂隙,地质条件较可研阶段发生了较大变化,因此而对地下厂房支护方案进行了重新研究,最终确定采用全断面钢筋混凝土衬砌的支护型式。经3年运行并经历2008年汶川5.12特大地震,表明大发水电站地下厂房支护设计是合适的。

Dafa hydropower station is located on the primary tributary Tianwa river on right bank of middle reach of Dadu river.The underground powerhouse area is near Moxi Fault which possibly occurs strong earthquake with basic earthquake intensity IX and complicated geological structures.After arch excavation,Fault f1 and other 4 sets of fractures are revealed,geological conditions are quite different from that studied in feasibility study stage,therefore,support scheme for underground powerhouse were analyzed again.Finally,full face reinforced concrete lining is adopted.After 3 years operation and experience of major Wenchuan Earthquake in 2008,it proves that design for underground powerhouse support at Dafa hydropower station is proper.