富水软岩隧道浅埋冲沟段管井降水技术探讨

Pipe Well Dewatering Technology in Shallow Buried Gully Section of Soft Rock Tunnel with Rich Water

为了解决地下水对隧道围岩软化效应,提高围岩自身承载力及稳定性,预防隧道开挖坍塌情况发生,通过对隧道富水软岩岩层节理分析,地下水存储状态,隧道涌水量预测,常用围岩加固措施经济性、安全性、加固效果比选,确定管井降水措施.通过降水技术去除岩土间孔隙水及裂隙水,消除岩土受地下水悬浮及填充效应,使岩土在自重作用下压缩空隙二次固结达到密实状态,最终达到提高岩土承载力及稳定性的目的.通过实践对比降水前后隧道洞内渗涌水量变化,证明管井降水对富水软岩地层提高岩土承载力效果良好,降低隧道开挖坍塌风险,可供类似地质隧道施工借鉴.

For the purposes of solving the softening effect of groundwater on sunounding rock of tunnel, improving the bearing capacity and stability of surrounding rock and preventing the occurrence of tunnel excavation collapse, the joint analysis of water-rich soft rock strata was carried out, the groundwater storage status was investigated, the tunnel water inflow was predicted. The comparison was made in terms of the economy and safety and effect of commonly used surrouruling rock reinforcement measuresin order to determine the measures of pipe well dewatering. By means of precipitation technology, the interstitial water and fissure water between rocks and soils were removed, and the suspension and filling effect of groundwater on rocks and soils was eliminated, so that the secondary consolidation of the compressed voids under the action of self-weight of rocks and soils could be achieved in a compact state, and finally the purpose of improving the bearing capacity and stability of rocks and soils was achieved. By comparing the variation of seepage and water inflow in tunnel before and after dewatering, it was proved that pipe well dewatering could improve the bearing capacity of rock and soil in water-rich soft rock strata, reduce the risk of collapse during tunnel excavation. It would be used for reference in similar geological tunnel construction.