浅埋暗挖法隧道施工过程地表沉降及洞室稳定性分析

发布时间：2018-01-30 16:22

本文关键词： 浅埋暗挖地表沉降隧道洞室稳定性随机介质理论层次分析法折减法　出处：《东华理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：我国近年采用浅埋暗挖法修筑的城市地下铁路隧道变得越来越多,然而使用这种工法施工隧道的过程中必将出现地表沉降及隧道洞室稳定性问题。过大的地表沉降会导致地表建筑物或构筑物失稳破坏,施工操作不当或支护不及时则会导致隧道洞室失稳坍塌。然而,由于城市施工场地复杂、水文地质条件较差,使得隧道施工过程中地表沉降及洞室稳定性问题更加突出;因此研究浅埋暗挖法隧道施工对地表沉降及洞室稳定性的影响具有十分重要的现实意义。本论文在对国内外相关文献资料进行广泛调研的基础上,以昆明市轨道交通线路为工程背景,采用理论分析、数值模拟、现场实测相结合的方法,对浅埋暗挖法隧道施工过程中地表沉降及隧道洞室稳定性问题进行了深入、系统的研究,取得的成果和主要内容如下:(1)分析总结了浅埋暗挖法施工隧道过程中影响地表沉降和隧道洞室稳定性的主要因素,以及隧道洞室破坏形式及特征;同时从地层细观结构失稳、地层损失以及土体固结沉降三方面对地表沉降进行理论分析。(2)简化了随机介质理论提出的地表横向沉降公式;并通过改变随机介质理论的原有假设——浅埋暗挖法施工隧道过程中土体由于扰动而产生排水固结,对简化的随机介质理论地表横向沉降公式进行了修正,最后得出了随机介质理论地表横向沉降简化修正公式;通过随机介质理论地表横向沉降简化修正公式与刘建航修正的Peck经验公式的对比,验证了地表横向沉降简化修正公式的正确性。(3)建立了层次分析法评价浅埋暗挖法隧道施工过程中洞室稳定性的递进层次结构模型,并计算出了各级指标的权重;同时采用强度折减法及位移折减法对层次分析法评价浅埋暗挖法隧道施工过程中洞室稳定性的结果进行修正,并得到了修正公式。(4)通过三维数值仿真计算得出了昆明市轨道交通线路隧道施工引起的地表沉降值及隧道洞室稳定性安全系数;将地表横向沉降仿真模拟值、实测值与简化修正公式计算所得的理论值进行对比,验证了地表横向沉降简化修正公式的实用性;仿真计算得出的隧道洞室稳定性安全系数为1.12,也就是说浅埋暗挖法隧道施工过程中洞室处于一般稳定状态。
[Abstract]:In recent years, there are more and more urban underground railway tunnels constructed by shallow excavation in China. However, the problems of surface settlement and tunnel cavern stability will occur in the process of tunnel construction by this method, and excessive surface settlement will lead to the failure of surface buildings or structures. Improper construction operation or untimely support will lead to the collapse of tunnel cavern instability. However, because of the complex construction site in the city, the hydrogeological conditions are poor. In the process of tunnel construction, the problems of surface settlement and cavern stability are more prominent. Therefore, it is of great practical significance to study the influence of shallow tunneling construction on surface subsidence and cavern stability. Taking Kunming rail transit line as the engineering background, the method of combining theoretical analysis, numerical simulation and field measurement is adopted. In this paper, the problems of surface settlement and tunnel cavity stability during the construction of shallow tunneling are studied in depth and systematically. The main achievements and contents are as follows: (1) the main factors which affect the surface settlement and the stability of tunnel cavern in the process of shallow tunneling are analyzed and summarized, as well as the failure forms and characteristics of tunnel caverns. At the same time, the theoretical analysis of ground surface settlement is made from three aspects of formation meso-structure instability, formation loss and consolidation settlement of soil, which simplifies the formula of surface lateral settlement proposed by random medium theory. And by changing the original assumption of random medium theory-shallow burying and digging method in the construction of tunnel process of soil drainage consolidation due to disturbance, the simplified formula of lateral surface settlement of random medium theory is modified. Finally, the simplified correction formula of surface lateral settlement in random medium theory is obtained. The comparison between the simplified correction formula of surface lateral settlement based on random medium theory and the Peck empirical formula modified by Liu Jianhang is presented. Verify the correctness of the simplified correction formula of surface lateral settlement. (3) establish a progressive hierarchical structure model of AHP to evaluate the stability of tunnel caverns in the construction process of shallow buried tunneling method. The weight of each index is calculated. At the same time, the strength reduction method and displacement reduction method are used to modify the results of AHP to evaluate the stability of tunnel in the process of shallow burying tunneling. The modified formula is obtained. (4) the surface settlement caused by the construction of Kunming rail transit tunnel and the safety factor of tunnel cavern stability are obtained by three-dimensional numerical simulation. By comparing the simulated values, the measured values and the theoretical values of the simplified correction formula, the practicability of the simplified correction formula of the surface lateral settlement is verified. The safety factor of tunnel cavern stability calculated by simulation is 1.12, that is to say, the cavern is in a general stable state during the construction of shallow burying tunneling method.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U456.3

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