隧道-滑坡斜交体系变形机理的模型试验研究

Research on the Deformation Mechanism Model Test of Tunnel-Landslide Skew System

研究目的:随着我国"一带一路"战略的实施,在中西部地区将会掀起新一轮的高速铁路建设高潮,隧道在线路总长度中占有的比例越来越大,导致隧道无法避绕滑坡的情况时有发生。在隧道-滑坡体系中,隧道走向与滑坡主滑方向有一定夹角时受力情况最为复杂,对隧道的施工、运营都造成严重威胁。目前我国对穿越滑坡的隧道设计和施工还没有形成统一的认识和标准以及完整的计算理论。本文以隧道-滑坡斜交体系为研究对象,通过模型试验,设置两个不同角度的隧道模型,模拟隧道开挖过程,并利用滑坡后部加载促使坡体向下蠕动,在隧道周围分别布置应变片对隧道的应变进行监测和分析研究,在坡体表面特征位置布置百分表监控位移情况。研究结论:(1)应变测试表明,隧道在竖向和水平两个方向上都产生变形,但是竖向变形显著大于水平变形;(2)两条隧道应变对比表明,隧道与滑坡主滑方向的相交角度越小,隧道的变形模式越接近悬臂结构;(3)位移测试表明,基岩与滑坡接触面处的坡顶沉降量最大,同时坡顶水平位移的最大点位于隧道进口和基岩的交接部位;(4)隧道应变和坡体位移差异分析表明,开挖隧道对滑体与基岩的扰动差异较大,造成滑体受扰动沉降较大,而基岩基本不动;在滑体内开挖隧道时围岩应力的释放程度显著大于在基岩内开挖隧道;(5)本研究结论可以为高速铁路穿越滑坡地区的设计和施工提供一定借鉴。

Research purposes： With the rapid development of the ＂ Silk Road Economic Belt and the 21st- Century Maritime Silk Road＂ , the total length of the tunnel have accounted for a growing share of the railway line, leading to that lots of tunnel must pass through the landslide. In the tunnel - landslide skew system, the force conditions is the most complicated when there is a certain angle between tunnel trend and landslide main sliding direction, which is a serious threat for the construction and operation of the tunnel. At present, it did not form a unified understanding and standard for the design and construction of tunnel in our country, and also there is no complete calculation theory. This paper takes the tunnel - landslide skew system as the study object, sets up two different angles of tunnel model by model tests, simulates tunnel excavation process, and uses the rear load to prompt landslide occurrence slope downward peristalsis, around the tunnel arranges for strain gage to monitor and analyze tunnel strain respectively, and in the slope surface arranges dial indicator to monitor the displacement. Research conclusions： （ 1 ） Strain tests showed that tunnels in the vertical and horizontal directions were deformed, but the deformation vertical direction was significantly larger than the deformation in the horizontal direction. （2） Two - strain contrast tunnel showed that the angle of intersection between the tunnel and landslide main sliding direction was smaller, the deformation mode of the tunnel was closer to the cantilever structure. （3） Displacement tests showed the settlement of slope top at the contact surface point of bedrock and landslide was largest while the maximum point of horizontal displacement of slope top was in the middle portion of the tunnel entrance and bedrock. （4） Strain and displacement of tunnel slope variance analysis showed that disturbance difference of tunneling on landslide and bedrock was large, resulting in the landslide settlement larger, and the bedrock basically fixed. When tunneling in the slide body release level of surrounding rock stress was significantly greater than the excavation of the tunnel in the bedrock. （5） The research can provide references for the design and construction of railway tunnel which passes through the areas of landslide.