马嘴隧道出口浅埋段围岩及边坡稳定性研究

发布时间：2018-01-18 11:19

本文关键词：马嘴隧道出口浅埋段围岩及边坡稳定性研究　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：经济的迅速发展、科学技术的进步,必然要求提供更加安全、舒适、快速、方便经济的交通运输方式,高速公路的大量修建因此成为必然。随着西部大开发战略的实施,高速公路建设已经由平原向山岭地区推进,与之相对应,公路隧道也得到迅猛发展。隧道工程往往是高速公路修建中的控制工程,隧道施工的周期和质量将直接影响到整条高速公路的建成。在山岭丘壑区,隧道不可避免的要穿越地质情况复杂地区,在山区隧道进出口段,一般会遇到浅埋段软弱破碎围岩,且伴有易滑塌边仰坡,其力学性质的复杂性常会严重影响隧道工程的正常施工。本文主要研究重庆南道高速公路马嘴隧道出口浅埋段,该段内围岩主要是粉质粘土与风化页岩,岩体软弱破碎,给隧道的修建带来了难度。本文据此开展了隧道洞口地段边坡及隧道变形机理研究工作。取得的成果有助于建立隧道洞口段边坡变形和稳定性理论,同时可为制定有效的工程措施提供理论指导。全文主要研究内容和结论有:①基于隧区工程地质条件,采用基于极限平衡理论的传递系数法来计算滑坡稳定性系数,计算出暴雨条件下边坡稳定系数小于指定安全值,需对边坡进行支挡措施,保障隧道进洞施工安全。②考虑径向收缩、椭圆化变形和竖向位移影响下的隧道周边位移边界条件后引入应力函数,推导及探讨了隧道周边的位移及应力公式。③在分析隧道边坡变形及下滑力基础上,计算了抗滑桩的锚固段,受荷段的剪力、弯矩及侧应力,通过侧应力验证其设计合理性。此外,分析了超前大管棚支护,超前小导管注浆等辅助施工措施支护机理及设计参数。④借助对出口段的数值分析,模拟实现隧道CD法开挖,得出分步开挖后,及时进行初期支护将有效控制隧道周边变形。分析模拟了隧道开挖后边坡的位移及应力分布,发现边坡前缘容易发生剪应力集中,应注意坡面防护。⑤现场监控观测了边坡地表的沉降,隧道出口段洞内拱顶沉降与周边收敛。将观测数据处理后得到拱顶沉降随分布开挖的变形规律,及地表沉降与隧道的空间位置的关系。
[Abstract]:With the rapid development of economy and the progress of science and technology, it is necessary to provide a more safe, comfortable, fast and convenient mode of transportation. With the implementation of the western development strategy, highway construction has been pushed from the plain to the mountain area, corresponding to it. Highway tunnel has also been developed rapidly. Tunnel engineering is often a control project in highway construction. The period and quality of tunnel construction will directly affect the completion of the whole highway. It is inevitable for the tunnel to pass through the complex geological area. In the entrance and exit section of the tunnel in the mountain area, it is usually met with weak and broken surrounding rock in the shallow buried section, and the slope is prone to slide. The complexity of its mechanical properties often seriously affects the normal construction of tunnel engineering. This paper mainly studies the shallow burying section of Mazui Tunnel exit of Chongqing Nandao Expressway, in which the surrounding rock is mainly silty clay and weathered shale. Rock mass is weak and broken. It is difficult to build the tunnel. Based on this, the research work on the slope and deformation mechanism of tunnel entrance section is carried out. The results obtained are helpful to establish the theory of slope deformation and stability at the tunnel entrance section. At the same time, it can provide theoretical guidance for the formulation of effective engineering measures. The main contents and conclusions of this paper are based on the engineering geological conditions of tunnel area. The transfer coefficient method based on the limit equilibrium theory is used to calculate the landslide stability coefficient, and the slope stability coefficient is less than the specified safety value under the rainstorm condition, so it is necessary to carry out the retaining measures for the slope. The stress function is introduced after considering radial contraction elliptical deformation and vertical displacement under the boundary condition of tunnel peripheral displacement to ensure the safety of tunnel entry. 2. Based on the analysis of slope deformation and sliding force, the shear force, bending moment and lateral stress of Anchorage section and loaded section of anti-slide pile are calculated. In addition, the supporting mechanism and design parameters of auxiliary construction measures such as pipe shed support, grouting with small pipe and so on are analyzed with the help of numerical analysis of the exit section. The CD method of tunnel excavation is simulated, and it is concluded that the early support will effectively control the deformation of tunnel periphery after step excavation. The displacement and stress distribution of the slope after tunnel excavation are analyzed and simulated. It is found that shear stress concentration is easy to occur in the front edge of the slope, and the slope surface settlement should be monitored and observed by monitoring and observing the slope surface protection .5 on the spot. The deformation law of the arch settlement along with the distribution of excavation and the relationship between the surface settlement and the space position of the tunnel are obtained by processing the observed data.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U451.2

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