隧道开挖对临近滑坡稳定性影响研究

发布时间：2018-02-02 20:31

本文关键词： 隧道开挖滑坡变形稳定性　出处：《重庆交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：在我国现代公路建设过程中，有许多隧道修建在山坡体内，，这些边坡或者滑坡常常会有各种各样的病害。经过大量的调查，滑坡的变形破坏与隧道开挖密切相关，针对预防边坡或滑坡的病害，本文开展了隧道临近滑坡稳定性及隧道变形机理的研究工作。近年来，由于引入了强度折减法，采用有限元法对滑坡稳定性分析，可以直接评估安全系数（强度折减系数），并且能够直观地描绘出滑坡的应力应变分布，同时也可以反映滑坡的渐进破坏过程，由于强度折减法这些特性是独一无二的，所以有限元极限分析法成为近年来研究的重点。本文在理论分析的基础之上，结合重庆万利万达项目猴子岩隧道工程实例，依据有限元强度折减法理论，针对隧道在不同开挖方式下对临近滑坡稳定性影响进行研究。主要内容包括： ①采用有限元强度折减法计算边坡或滑坡稳定性安全系数，是以ANSYS程序自动计算不收敛为滑坡失稳状态判定依据，计算结果与工程实际有较好的一致性； ②滑坡在自重应力场下，随着强度折减系数的增大，坡脚首先产生塑性应区，塑性区逐渐向坡体上方发展，塑性应变区面积渐渐增大，直至折减到某一个值计算不收敛，这时模型达到极限破坏状态； ③随着隧道埋深加大，隧道开挖对临近滑坡稳定性影响逐渐降低，滑坡稳定性还受隧道开挖方式的影响； ④隧道采用全断面开挖时，此种开挖方式对隧道围岩扰动较大，临近滑坡的变形也会增大，计算获得的安全系数为2.14，要做好滑坡防护与治理工作； ⑤隧道采用先左洞再右洞上下台阶法开挖，计算获得的安全系数为2.196，相比于全断面开挖滑坡稳定性安全系数增大一些，但仍需在施工过程中加强监控量测； ⑥隧道采用先右洞再左洞上下台阶法开挖，计算获得的安全系数为2.224，是三种开挖方式中最大值，这也表明，此种开挖方式对临近滑坡稳定性影响最小，尽管也会使滑坡产生一定的塑性应变，但是是能够满足实际施工要求的； ⑦隧道开挖与滑坡变形是相互作用的，两者的关系密不可分，故数值分析结果应充分结合工程实际，这样才能使得有限元分析计算结果作为实际施工措施的理论支撑。
[Abstract]:In the process of modern highway construction in China, there are many tunnels built in the hillside, these slopes or landslides often have a variety of diseases, after a large number of investigations. The deformation and failure of landslide is closely related to tunnel excavation. In order to prevent slope or landslide disease, this paper has carried out the research on the stability of tunnel near landslide and the mechanism of tunnel deformation in recent years. Because the strength reduction method is introduced and the stability of landslide is analyzed by finite element method, the safety factor (strength reduction factor) can be directly evaluated, and the distribution of stress and strain of landslide can be described intuitively. At the same time, it can also reflect the gradual failure process of landslide. Because these characteristics of strength reduction method are unique, the finite element limit analysis method has become the focus of research in recent years. On the basis of theoretical analysis, combining with the example of Monkey Rock Tunnel of Wan-li Wanda Project in Chongqing, this paper bases on the theory of finite element strength reduction. The influence of tunnel excavation on the stability of adjacent landslide is studied. The main contents are as follows: 1. Using the finite element strength reduction method to calculate the safety factor of slope or landslide stability is based on the automatic calculation of ANSYS program. The calculation results are in good agreement with the engineering practice. 2 under the gravity stress field, with the increase of the strength reduction coefficient, the slope foot first produces the plastic zone, the plastic zone develops gradually above the slope body, and the area of the plastic strain zone increases gradually. The model does not converge until it is reduced to a certain value, and the model reaches the limit failure state. (3) with the increase of the buried depth of the tunnel, the influence of tunnel excavation on the stability of the adjacent landslide decreases gradually, and the stability of the landslide is also affected by the excavation mode of the tunnel; (4) when the tunnel is excavated with full section, the tunnel surrounding rock will be disturbed greatly by this excavation method, and the deformation of adjacent landslide will also increase. The calculated safety factor is 2.14, so it is necessary to do a good job in landslide protection and treatment. (5) when the tunnel is excavated by the method of first left hole and then right hole, the calculated safety factor is 2.196, which is a little higher than that of the whole section excavation landslide stability safety factor. However, it is still necessary to strengthen the monitoring and measurement in the construction process. 6 the tunnel is excavated by the method of first right hole and then left hole, and the calculated safety factor is 2.224, which is the maximum of the three excavation modes, which also indicates that. This kind of excavation method has the least influence on the stability of the adjacent landslide, although it can make the landslide produce some plastic strain, it can meet the actual construction requirements. 7Tunnel excavation and landslide deformation are interacted, the relationship between them is inseparable, so numerical analysis results should be fully combined with engineering practice. Only in this way can the finite element analysis result be used as the theoretical support of practical construction measures.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455;U418.55

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