秦岭隧洞椒溪河段工程地质条件及涌水特征分析

隧洞突涌水是山岭隧洞施工中遇到的主要地质灾害之一。秦岭隧洞下穿椒溪河段,隧洞埋深浅,岩性以大理岩为主,断裂构造发育,形成良好的富水区,隧洞穿越时发生3次大的突涌水现象。施工中先期安排地质超前预报,再实施超前水平钻孔进行验证,并利用超前水平钻孔进行双液浆预注浆。最终采用多种注浆形式对洞内突涌水进行处理,洞外河床修筑挡水围堰及防渗墙有效减少了洞内涌水,确保秦岭隧洞顺利通过椒溪河段落。

The Analysis of Geological Conditions and Water Gushing in Jiaoxihe Section of Qinling Tunnel

Water inrush is one of the main geological hazards in the construction of the tunnel. Qinling tunnel passes through Jiaoxi River where it is buried shallow in lithology dominated with marble,developed faults and rich water. Big water inrushing occurred three times when tunneling passed the river. To prevent disasters, advanced geological forecast was conducted ahead of construction and horizontal boreholes were drilled for verification. Additionally, pre-grouting was implemented with advanced horizontal drilling. Finally,multiple grouting,the combination of grouting in tunnel and retaining cofferdam and cutoff wall outside the tunnel were applied to minimize water gushing and to guarantee successful tunneling.