隧道平行穿越滑坡体的变形特征及控制技术

香丽(香格里拉—丽江)高速公路沿线存在较多穿越滑坡体的隧道,其中比较常见的是隧道平行穿越滑坡体。本文以香丽高速公路一隧道为背景,对平行穿越的隧道-滑坡问题的变形特征和受力机制开展研究,并讨论其控制技术。研究结果表明:隧道平行穿越滑坡体时,隧道拱部比底部所受应力更大,隧道拱部位置受拉,底部位置受压,在隧道受拉与受压的过渡位置有拉压中性区分布;隧道主要的变形位置位于滑带附近,且隧道拱部首先出现剪切裂缝,之后向左右墙延伸扩展,最后裂缝发展并贯通到隧道底部,引起路基出现错台沉降,从而导致隧道发生剪切破坏;提出的钢花管多次分段控制注浆技术可以有效解决施工安全性低,施工周期长的问题,达到了治理滑坡体病害和提高隧道稳定性的双重作用。

Deformation Characteristics and Control Technology of Tunnels Passing Through Landslide in Parallel

There are many tunnels passing through the landslide mass along the Shangri-La-Lijiang Expressway,themost common one is that the tunnel passes through the landslide mass in parallel.Based on a tunnel of Shangri-LaLijiang Expressway,the deformation characteristics and stress mechanism of tunnel landslide were studied,and thecontrol technology was discussed.The research results show that the tunnel arch is more stressed than the tunnel bottomwhen the tunnel passes through the landslide mass in parallel.The tunnel arch is under tension and the tunnel bottom isunder compression.There is a tension-compression neutral zone at the transition position of the tunnel under tension andcompression.The main deformation position of the tunnel is near the sliding zone,and the shear cracks appear in thetunnel firstly,then extend to the left and right walls,and finally the cracks develop and penetrate to the tunnel bottom,which causes the dislocation settlement of the subgrade and leads to the shear failure of the tunnel.The proposed multistage controlled grouting technology with steel-flower tube can effectively solve the problems of low construction safetyand long construction period,and achieve the dual functions of controlling landslide mass diseases and improving thestability of tunnel.