双洞穿越滑坡段高陡边坡稳定性分析

发布时间：2018-06-26 08:29

本文选题：边坡工程 + 双洞隧道　；参考：《西南交通大学》2014年硕士论文

【摘要】：随着我国经济建设的不断发展,水利水电、公路铁路工程建设事业也在突飞猛进,出现了越来越多的高陡边坡。在边坡中开挖隧道是公路工程中常常会采用的方式。尤其是在高陡边坡中开挖双洞隧道,将对边坡将造成扰动,开挖后边坡的稳定性问题以及边坡的位移、应力分布需要密切关注,一旦出现问题将影响边坡工程的安全。然而,对于双洞隧道的空间布置发生改变,或隧道的施工模式及施工顺序不同时,边坡稳定性受隧道开挖的影响有何规律,边坡的位移、应力分布有何特点,还须做进一步的努力研究。研究结果对于高边坡条件下隧道施工模式的优化以及隧道空间结构的合理布置,具有重要价值。本文以卡杨公路隧道双洞穿越滑坡泥石流高陡边坡为背景,综合运用现场调查及文献分析、灰关联法、理论分析以及数值模拟方法,对卡杨公路工程高陡边坡稳定因素的敏感性进行了理论研究,并针对开挖前边坡的自然稳定性及双洞穿越条件下隧道空间结构布置、隧道施工模式对边坡稳定的影响进行了详细的研究。本文的主要研究内容及结论如下： 1、针对雅砻江卡拉、杨房沟水电站交通专用公路工程中的双洞穿越高陡边坡的边坡稳定问题,依据隧道及边坡工程理论,结合现场调查及文献综合分析方法,系统总结出了影响边坡稳定的主控影响因素主要为岩土体重度ρ、边坡坡度α、粘聚力c、内摩擦角(?)和地下水位hw。进而依据灰色关联分析法,在设计5因素6水平的基础上建立了均匀实验模型,对主控因素影响边坡稳定的敏感性进行了灰关联分析,发现摩擦角对边坡稳定的影响最为敏感,其次是重度、粘聚力和边坡坡度,三者均为非常重要的敏感因素。 2、针对卡杨公路工程区域边坡条件的复杂性,将边坡分为洞口段边坡、深埋段边坡和滑坡段边坡,采用数值模拟的方法对隧道开挖前的自然边坡稳定性进行了分析,结果表明：隧道深埋段开挖后对边坡扰动小而使边坡稳定性较好；而滑坡段边坡安全系数为1.10,已接近极限平衡状态,隧道开挖前须特别重视边坡的支护问题；洞口段边坡开挖前基本处于稳定状态,但由于隧道浅埋,隧道开挖可能会对边坡的稳定造成影响,应密切关注边坡变形的变化。 3、采用数值模拟的方法,研究了双洞穿越高陡边坡时隧道的不同空间结构布置对边坡稳定性的影响,得到了在隧道不同空间结构布置情况下开挖完成后边坡的应力、位移特征。研究结果表明,边坡随隧道水平间距的减小而趋于不稳定,当双洞隧道水平间距不同时,间距越大,隧道的开挖对边坡的影响越小,当间距过小(如本文中间距15m)时,边坡将产生极大的变形而滑动破坏,而靠边坡临空面一侧隧道对边坡稳定起控制性作用,因此隧道离临空面越远,对边坡稳定性影响越小；双洞竖向埋深变化时,隧道深埋要优于浅埋和中等埋深,埋深过浅对于边坡的稳定性是最不利的,随隧道埋深的减小,隧道开挖的影响范围逐渐由坡脚转移至坡顶处,埋深过浅易发生上方岩土体向隧道的坍塌,深埋隧道仅对坡脚有一定影响,且坡脚最终总体与另外两种情况下的数值相差不大。以上结论对于隧道空间布置的合理选择提供了理论依据。 4、对双洞穿越高陡边坡时隧道的不同施工模式和施工顺序对边坡稳定性的影响进行分析,得到了不同情况下边坡的应力、位移变化规律。研究结果表明,左洞先行的台阶法施工,由于隧道开挖过程中应力分布释放,且左洞先行使边坡应力二次分布有更多的调整空间,开挖后边坡整体位移最小,因此对工程安全是最有利的；而右洞先行的全断面法对工程安全最为不利,原因是全断面法开挖步的减少和右洞先行的施工模式都不利于应力的释放调整,尤其是右侧隧道开挖后,坡面就产生了较大的位移,致使后续左洞施工对边坡位移的影响都变得不可忽略。此结论对于隧道工程中的施工工法的选择具有一定的参考意义,在与本文围岩、边坡条件相似的工程中应尽量采用左洞先行的台阶法进行隧道的开挖,有利于控制边坡的位移。
[Abstract]:With the continuous development of China's economic construction, water conservancy and hydropower, highway and railway engineering construction are also advancing rapidly. There are more and more high and steep slopes. Tunnel excavation in the slope is often used in highway engineering. The excavation of double tunnel tunnel in high and steep slopes will cause disturbance to the slope and the slope after excavation. The stability problem and the displacement of the slope and the stress distribution need to be closely concerned. Once the problems arise, the safety of the slope engineering will be affected. However, the spatial arrangement of the tunnel is changed, or the construction mode and the order of the tunnel construction are different, the influence of the slope stability on the excavation of the tunnel, the displacement of the slope and the stress distribution The research results are of great value to the optimization of the tunnel construction mode and the rational layout of the tunnel space structure under the high slope conditions.
Based on the background of the high and steep slope of the landslide debris flow in the cayang highway tunnel, the sensitivity of the stability factors of the high and steep slope of the cayang highway project is theoretically studied by using the field investigation and literature analysis, the grey correlation method, the theoretical analysis and the numerical simulation method, and the natural stability and double penetration of the slope before excavation are also studied. The influence of tunnel construction on slope stability is studied in detail under the condition of tunnel layout. The main contents and conclusions are as follows:
1, based on the tunnel and slope engineering theory, according to the tunnel and slope engineering theory, according to the tunnel and the slope engineering theory, according to the tunnel and the slope engineering theory, the main controlling factors affecting the slope stability mainly are the severe rock and soil mass P, the slope gradient of the slope, according to the tunnel and the slope engineering theory. Cohesive C, internal friction angle (?) and groundwater level hw. then based on the grey correlation analysis method, a uniform experimental model is established on the basis of 5 factors and 6 levels, and the sensitivity of the main control factors to slope stability is analyzed by grey correlation analysis. It is found that the friction angle is most sensitive to the effect of slope stability, followed by severe, cohesive force and slope. Slope, the three are very important sensitive factors.
2, according to the complexity of the slope conditions in the area of the Ka Yang highway project, the slope is divided into the hole slope, the deep buried slope and the slope of the landslide section. The numerical simulation method is used to analyze the stability of the natural slope before the tunnel excavation. The results show that the deep tunnel excavation is small and the slope stability is better after the excavation of the deep tunnel. The slope safety factor of the landslide section is 1.10, which is close to the limit equilibrium state. The slope support must be paid special attention to before the excavation of the tunnel. The slope of the tunnel section is basically in a stable state before the excavation, but the tunnel excavation may affect the stability of the slope because of the shallow tunnel excavation.
3, using the numerical simulation method, the influence of the different spatial structure layout of the tunnel through the high steep slope is studied. The stress and displacement characteristics of the slope are obtained after the excavation of the tunnel with different spatial structures. The results show that the side slope tends to be unstable with the decrease of the horizontal distance of the tunnel. When the horizontal spacing of the tunnel is different, the greater the distance between the tunnel, the smaller the influence of the tunnel excavation to the slope. When the distance is too small (such as the middle distance to 15m), the slope will have a great deformation and sliding failure, and the side slope side tunnel on the side of the air side will play a controlling role on the slope stability, so the farther the tunnel is from the air surface, the influence on the stability of the slope is more. When the vertical buried depth changes, the deep buried depth of the tunnel is better than the shallow and medium buried depth. The depth of the buried depth is the most unfavorable to the stability of the slope. With the decrease of the depth of the tunnel, the influence range of the tunnel excavation is gradually transferred from the foot to the top of the slope. The depth of the buried depth is easy to collapse to the tunnel, and the deep buried tunnel is only to the foot of the slope. It has some influence, and the end of the slope is not quite different from the other in the other two cases. The above conclusion provides a theoretical basis for the rational selection of the tunnel space layout.
4, the influence of the different construction modes and construction sequence on the slope stability is analyzed in the tunnel crossing high and steep slope, and the stress and displacement law of the slope are obtained under different conditions. The results show that the step method of the left hole first step method is released due to the stress distribution in the tunnel excavation, and the left hole makes the slope stress first. The two distribution has more adjustment space, the whole displacement of the slope is the smallest after excavation, so it is the most favorable for the safety of the project, and the full section method before the right hole is the most unfavorable to the safety of the project. The reason is that the reduction of the full section method and the construction mode before the right tunnel are not conducive to the adjustment of stress release, especially the excavation of the right tunnel. After that, the slope surface has a larger displacement, which causes the influence of the construction of the subsequent left hole to the slope displacement. This conclusion has a certain reference significance for the selection of the construction method in the tunnel engineering, and the left hole first step method should be used in the project which is similar to the surrounding rock and the slope condition. It is beneficial to control the displacement of the slope.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U452.11

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