巨型“圆筒+倒锥体”结构尾调室井身段衬砌施工

Lining Construction for the Shaft Section of Tailwater Surge Chamber with a Giant"Cylinder+Inverted Cone"Structure

以往地下电站尾调室的体型多以规则的圆筒式或者矩形结构进行设计,但在特殊地质条件下,为确保洞室结构安全,其设计结构体型不得不进行异与常规的优化设计,白鹤滩水电站右岸8号尾水调压室就是这其中的典型代表作品之一,在高地应力、柱状节理、大型层间错动带、陡倾角断层等不良地质条件下,设计巧妙的采用了“圆筒+倒锥体”的井身段结构,巧妙地实现了调压室井身段由A48 m过渡到穹顶的A39.2 m,极大减小了调压室穹顶跨度,使整个穹顶呈流线型结构。但该设计导致调压室井身上部边墙处于倒悬状态,给施工带来了极大的挑战。

In the past,the shape of tail surge chamber of underground power plants was mostly designed with a regular cylindrical or rectangular structure.However,under special geological conditions,in order to ensure the safety of the tunnel structure,the design structure shape has to be optimized differently from conventional design.The No.8 tailwater surge chamber on the right bank of Baihetan Hydropower Station is one of the typical representative works.Under adverse geological conditions such as high ground stress,columnar joints,large interlayer fault zones,and steep dip faults,a clever design of a"cylinder+inverted cone"wellbore section structure was adopted.It cleverly transitions the section of surgechamber shaft from A48 m to A39.2 m of the dome,greatly reducing the span of the pressure regulating chamber dome and making the entire dome a streamlined structure.However,this design resulted in the upper side wall of surgechamber being in an inverted state,posing a great challenge to construction.