考虑渗流作用的富水区域公路隧道围岩稳定性研究

Research on Stability of Surrounding Rock of Highway Tunnel in Water Rich Area Considering Seepage

以山西某单向两车道公路隧道富水段为研究背景,基于渗流相关理论考虑周边地下水的影响,运用FLAC3D软件进行建模分析,得出是否考虑地下水渗流影响两种情况下,隧道围岩渗流场、位移场、塑性区的变化规律并对隧道围岩稳定性进行评估。研究结果表明:隧道周边围岩渗流场形似“漏斗”,由于水压差较大拱脚处存在失稳破坏可能;考虑渗流的隧道整体围岩竖向位移均增大,拱顶与拱底处位移过大可能导致失稳;考虑渗流作用的隧道各部位塑性区较之无渗流显著增大,边墙与拱脚处发生明显剪切变形,因此应加强边墙与拱脚防排水设计以防发生突水涌泥。研究表明隧道富水区域段应重视地下水的作用,加强防排水设计且保证施工安全性,对公路隧道富水区域设计与施工作业提供一定参考价值。

Taking the water rich section of a one-way two-lane highway tunnel in Shanxi province as the research background,based on the seepage related theory,considering the influence of surrounding groundwater,FLAC3D software is used for modeling analysis,and the change rules of seepage field,displacement field and plastic zone of tunnel surrounding rock are obtained under the two conditions of considering the influence of groundwater seepage,and the stability of tunnel surrounding rock is evaluated.The research results show that:the seepage field of surrounding rock around the tunnel looks like a"funnel",and there is a possibility of instability and failure at the arch foot due to the large water pressure difference;the vertical displacement of the whole surrounding rock of the tunnel considering seepage increases,and the excessive displacement at the crown and bottom of the arch may lead to instability;the plastic zone of each part of the tunnel considering seepage is significantly larger than that without seepage,and obvious shear deformation occurs at the side wall and arch foot.Therefore,the waterproof and drainage design of the side wall and arch foot should be strengthened to prevent water inrush and mud gushing.The research shows that the role of groundwater should be paid attention to in the water rich area of the tunnel,and the waterproof and drainage design should be strengthened to ensure the construction safety,so as to provide a certain reference value for the design and construction of the water rich area of the highway tunnel.