贾家山1号隧道洞口仰坡失稳破坏及治理效果研究

发布时间：2018-03-13 11:42

本文选题：隧道洞口边坡　切入点：稳定性分析　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：隧道洞口段地质灾害严重影响着隧道工程的建设和运营，较为突出的是洞口边仰坡稳定性问题。本文以贾家山1号隧道洞口边仰坡失稳破坏诱发山体滑坡的工程实例为研究对象，运用工程类比法、数值计算法和现场监测数据分析，对洞口边坡稳定性、失稳影响因素和隧道开挖模型进行了较为深入的研究。现场监测和勘察表明：贾家山1号隧道洞口边仰坡失稳破坏主要经历了零星破坏、局部破坏和整体破坏三个阶段。综合分析降雨系数、施工工序对应的沉降曲线的相关性，得出施工期间连续降雨是洞口边仰坡失稳破坏的主导因素。通过分析类似工程的地表沉降数据得出：由降雨引起地表沉降的滞后时间约在24h~48h之间；施工工序引起的地表沉降量中，核心土开挖引起的地表沉降量相对最大。建立贾家山1号隧道三维模型，通过分析动态施工下洞口区域的应力分布和变形特征得出：隧道施工开挖造成边仰坡坡脚应力集中，出现塑性变形，导致坡体的抗滑力小于下滑力，坡体后缘发生张拉破坏，诱发边坡失稳。连续降雨使土体的含水量增大，土体力学参数发生变化，，这是边坡失稳破坏的主要原因。根据贾家山1号隧道山体仰坡的治理方案，利用简化bishop法、janbu法和强度折减法计算典型滑面的安全系数分别为1.47、1.466和1.50，治理方案有效的提高了滑坡的安全系数；通过有限元法搜索出治理后滑坡的潜在滑面和剪出口，主要集中在治理方案中的第二、三级平台处，施工时此处需加强支护，并做好防排水措施。
[Abstract]:The geological disasters at the entrance of the tunnel seriously affect the construction and operation of the tunnel project. The problem of slope stability at the entrance of the Dongkou is prominent. This paper takes the engineering example of landslide induced by the instability of the slope at the entrance of Jiajashan No.1 Tunnel as the research object, applies the engineering analogy method, the numerical calculation method and the field monitoring data analysis. In this paper, the slope stability, instability factors and tunnel excavation model are studied. Field monitoring and investigation show that the instability of the slope at the entrance of Jiajashan No.1 Tunnel has experienced three stages: sporadic destruction, local failure and overall destruction. The correlation of rainfall coefficient and settlement curve corresponding to the construction process is analyzed synthetically. It is concluded that continuous rainfall during construction is the main factor of instability and failure of slope on the edge of the hole. By analyzing the surface subsidence data of similar projects, it is concluded that the lag time of surface subsidence caused by rainfall is about 24 h or 48 h; In the surface settlement caused by construction process, the surface settlement caused by core soil excavation is the largest. The three-dimensional model of Jiayashan No.1 Tunnel is established. By analyzing the stress distribution and deformation characteristics of the opening area under dynamic construction, it is concluded that the stress concentration and plastic deformation occur at the foot of the slope caused by the excavation of the tunnel construction. As a result, the slip resistance of slope is smaller than that of slide, and the tension failure occurs at the back edge of slope, which induces slope instability. Continuous rainfall increases the water content of soil and changes the mechanical parameters of soil, which is the main reason of slope instability. According to the control scheme of vertical slope of No. 1 tunnel in Jiajashan, the safety coefficient of typical sliding surface calculated by simplified bishop method and strength reduction method is 1.47 ~ 1.466 and 1.50, respectively. The safety factor of landslide is improved effectively by the control scheme. Through the finite element method, the potential sliding surface and shear outlet of the landslide after treatment are found, which are mainly concentrated in the second and third grade platform of the treatment scheme, where the support should be strengthened and the measures of waterproof and drainage should be done well during construction.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U453.1;U457.2

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