浅埋偏压隧道的围岩自稳性研究及工程应用

发布时间：2018-06-19 04:39

本文选题：公路隧道 + 偏压浅埋　；参考：《广西大学》2017年硕士论文

【摘要】：通过长期的地下结构支护实践,科研人员发现隧道周围一定范围内的围岩具有自承能力和自稳性,即自然平衡现象。实践证明隧道围岩在一定状态下是可以自稳的。现行公路隧道实际工程情况复杂多变,由于现阶段围岩分级的单个级别跨度比较大,对围岩的稳定性把握不够精细,围岩实际状况了解不够全面,导致隧道设计和施工的方案比较保守。因此,围岩的稳定性方面存在细化的空间,需要把握好围岩数据的准确性,方可科学地把握和设计整个隧道工程。考虑国内外对围岩的稳定性研究方向较多,因此本文在分析围岩稳定性时,着重考虑目前影响隧道工程中的重要因素。实际工程中,许多公路隧道受到浅埋和偏压的影响较大,为更准确地了解围岩的实际状况,本文依托广西南宁玉象隧道,考虑采用埋深和偏压两个指标,用数值模拟的方法模拟隧道开挖后毛洞的稳定性,通过稳定性结果对围岩进行分级,即自稳性分级。在此基础上,用数值模拟的方法针对不同自稳等级围岩提出对应的优化初期支护方案,并通过实际施工监测数据进行对比和验证。根据围岩稳定性分级进而相应地优化隧道设计,节约资源和降低建设成本。研究结果表明,根据埋深和偏压角度两个指标,可将该隧道的自稳性划分为三个级别,并根据这三个等级,进而对隧道初期支护方案进行优化,其中,在优化方案中,将材料的用量和参数如湿喷混凝土的厚度优化为20cm～50cm厚,锚杆为2m～5m,钢拱架将22号工字钢改为18号工字钢。实际监控测量数据与优化方案的模拟数据较接近,因此,优化方案是可行的。在安全施工的前提下,对初期支护的优化取得—定的效果。研究结果对类似受到浅埋偏压影响隧道的初期支护设计和施工具有参考价值。
[Abstract]:Through the long-term practice of underground structure support, the researchers found that the surrounding rock around the tunnel has self-supporting capacity and self-stability, that is, natural balance phenomenon. Practice has proved that the surrounding rock of the tunnel can be self-stable in a certain state. The actual engineering situation of current highway tunnel is complex and changeable. Since the single grade span of surrounding rock classification is relatively large at present, the stability of surrounding rock is not well grasped, and the actual condition of surrounding rock is not fully understood. The scheme of tunnel design and construction is conservative. Therefore, there is a fine space for the stability of surrounding rock, so it is necessary to grasp the accuracy of surrounding rock data in order to scientifically grasp and design the whole tunnel project. Considering that there are many research directions on the stability of surrounding rock at home and abroad, this paper focuses on the important factors that affect the stability of surrounding rock in tunnel engineering. In actual engineering, many highway tunnels are greatly affected by shallow burying and bias pressure. In order to understand the actual condition of surrounding rock more accurately, this paper, relying on Nanning Jade Xiang Tunnel in Guangxi, considers adopting two indexes of buried depth and bias pressure. The stability of the tunnel after excavation is simulated by numerical simulation, and the stability of surrounding rock is classified by the stability results, that is, self-stability classification. On this basis, the numerical simulation method is used to propose the corresponding initial support scheme for the surrounding rock of different self-stability grade, and the comparison and verification are carried out through the actual construction monitoring data. According to the classification of surrounding rock stability, the tunnel design is optimized accordingly, which saves resources and reduces construction cost. The results show that according to the two indexes of buried depth and bias angle, the self-stability of the tunnel can be divided into three levels, and according to these three grades, the initial support scheme of the tunnel can be optimized, among which, in the optimization scheme, The material content and parameters such as the thickness of wet shotcreting concrete are optimized to be 20cm~50cm thickness, the anchor rod is 2 mand 5 m, and the steel arch frame is changed from 22 I-steel to 18 I-beam steel. The actual monitoring and measurement data are close to the simulation data of the optimization scheme, so the optimization scheme is feasible. In the premise of safe construction, the initial support optimization achieved-fixed results. The results are valuable for the initial support design and construction of tunnels affected by shallow bias voltage.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451.2

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