侧部水压充填型岩溶隧道衬砌结构位移性状分析

Analysis on displacement characteristic of lining structure of karst tunnel lateral filled with water

以宜万铁路某岩溶隧道为例,利用有限差分软件FLAC3D对隧道左侧部存在高压充水溶洞的隧道衬砌结构位移特征进行了数值模拟研究,并与现场监测结果进行了比较分析,同时还分析了溶洞内水压的变化以及充水溶洞与隧道间距的变化对隧道衬砌结构位移的影响。结果表明:靠近充水溶洞侧的衬砌结构水平位移值要比远离充水溶洞侧的衬砌结构水平位移值要大,其中左边墙的水平位移是右边墙的2倍左右;拱顶和左拱肩之间的区域有较大的向下竖向位移,左墙脚和仰拱底之间的区域有较大的向上竖向位移;整个衬砌结构向远离充水溶洞侧变形。随着溶洞内水压逐渐增大以及充水溶洞与隧道间距离的逐渐减小,衬砌结构特征位置处的水平位移和竖向位移均有不同程度的增大;沿着隧道的轴向,断面越靠近充水溶洞其受影响程度就越大。

Take a karst tunnel in Yichang-Wanzhou railway as an example,by using the finite difference software FLAC3D the surrounding rock deformation of karst cave in the side of tunnel is simulated and compared with the field monitoring result. At the same time,a numerical analysis concerning the influence of the change of water pressure and distance between karst cave and tunnel is carried out. The results show that the horizontal displacement of lining structure near the karst cave is larger than that away from the karst cave,and the horizontal displacement of the left side wall is twice than the right; the zone between crown and the left spandrel has large downward vertical displacement,and the zone between the left wall footing and inverted arch has large upward vertical displacement; the whole lining structure is deformed toward away from the karst cave. With water pressure gradually increase and the decrease of the distance between the karst cave and the tunnel,the horizontal displacement and vertical displacement of lining structure at the characteristic positions increase at different extents; along the tunnel axial direction,the nearer of the cross section to the karst cave,the greater the infulunce degree.