砂化白云岩隧道突泥涌水处治技术

Treatment Technology of Mud Inrush in Sandy Dolomite Tunnel

我国西南地区广泛分布着以白云岩为代表的碳酸盐岩,这种岩体在有水的情况下易出现砂化现象。营盘山隧道工程D2K169+023~+195施工段,白云岩岩溶强烈发育,局部存在砂化现象。施工过程中在岩溶水作用下先后发生初支变形、左侧边墙溜坍和掌子面突泥涌水问题,危害施工安全。论文针对掌子面突涌问题,为超前泄水降压和探测溶洞发育规模,于路线右侧增设了迂回导坑,确定按“泄水降压、注浆加固、管棚超前”的原则,同时为防止地下水软化,隧底采用钢管桩进行加固,最终隧道安全通过该大型充填溶洞,为后续相关问题的解决提供了经验。

Carbonate rocks represented by dolomite are widely distributed in Southwest China.This kind of rock mass is prone to sandy phenomenon in the presence of water.The D2K169+023~+195 construction section of Yingpanshan tunnel project,where dolomite karst is strongly developed and there is local sandification.During the construction,under the action of karst water,the problems of initial support deformation,left side wall collapse and tunnel face mud inrush and water inrush occurred successively,endangering the construction safety.In this paper,a circuitous pilot pit is added on the right side of the route to solve the problem of sudden inrush in the tunnel face in order to release water and reduce pressure in advance and detect the development scale of karst caves,It is determined to follow the principle of"water release and pressure reduction,grouting reinforcement and advance of pipe shed",at the same time,in order to prevent groundwater from softening,steel pipe piles were used at the bottom of the tunnel for reinforcement,and finally the tunnel safely passed through the large filled karst cave,which provided experience for the solution of subsequent related problems.