黔桂铁路那马隧道施工方案浅析

黔桂铁路扩能改造工程的那马隧道设计全长2788m，地质松散破碎，而且穿过多处断层。施工中发现出口部分段落处于山体滑坡层上，地质情况相对复杂。由于工期紧迫，施工方案选定中采取增设斜井增加工作面的方法，而且针对各地质不良段，分别采用管棚预支护结合小导管注浆加固突泥体及周边围岩、钢拱架加强支护等措施，成功安全穿越不良地质段。对此隧道施工方案以及不良地质段处理措施进行介绍。

Analysis on Construction Scheme of Nama Tunnel

Nama tunnel, which is an integral part of Qian-Gui railway updating project, is designed to be 2 788 m long. Crossing several fault zones, the tunnel has poor geological conditions. The exit portion of the tunnel is located on slide slopes, which has extremely complex geological conditions. Due to the tight construction schedule of the tunnel, it is determined to install an inclined shaft so as to provide more working faces. Such reinforcement measures as pipe roof, forepoling, grouting and steel arches are taken so that the tunnel can cross the fractured zones successfully. In the paper, the construction scheme of the tunnel and the countermeasures taken to cope with the poor geological conditions are presented.