龙洞水电站排风洞深厚崩坡堆积体洞挖施工技术

Tunnel Excavation Construction Technology for Ventilation Tunnel in Thick Colluvial Deposit at Longdong Hydropower Station

龙洞水电站地下厂房系统排风洞总长218.85 m,洞口及覆盖层段主要由崩坡积块碎石土和块碎石构成,厚度较大,结构松散,成洞条件极差。施工中主要采用超前固结灌浆、超前管棚、工字钢格栅拱架、网喷等多种支护方式结合的方法进行施工,成功地解决了排风洞崩堆积体进洞的难题。

Ventilation tunnel in underground powerhouse system at Longdong hydropower station is 218. 85m long. Tunnel portal and overburden sections are largely composed of colluvial and deluvial block and broken stone soil with thick and loose structure and it is difficult to form a tunnel. In construction,several support methods,such as advance consolidation grouting,advance pipe roof support,I-bar grid arch and wire mesh and shotcrete,are combined. Excavation in ventilation tunnel portal was carried out successfully in the colluvial deposit. The construction technology is presented in this paper.