昔格达地层隧道围岩稳定性相似模型试验研究

发布时间：2018-07-07 08:37

本文选题：昔格达地层 + 围岩稳定性分析　；参考：《西南交通大学》2015年硕士论文

【摘要】：昔格达地层是一套特殊的半成岩地层,其工程性质一般介于极软岩和土之问。鉴于其较差的工程性质,以往在昔格达地层中基本没有修建过铁路和公路隧道。因此,在昔格达地层中修建高速公路隧道是一个崭新的课题,并值得去研究和探索。本论文以丽攀高速公路华坪隧道为依托,通过相似模型试验方法进行了昔格达地层隧道围岩稳定性研究。本次研究中,首先通过搜集华坪隧道相关文献资料并结合现场地质勘查,对隧道的工程地质背景有了详细的掌握。接下来,通过室内土工试验得出隧道围岩的相关物理力学参数。在完成以上准备工作后,进行了相似模型试验,并通过试验得到了下列主要研究成果：一、通过对华坪隧道进行开挖模拟,并同时监测隧道围岩各个方向上的应变情况,得出了隧道开挖后围岩的变形规律。(1)隧道开挖后,围岩应变量最大处在拱顶位置,其次为拱脚,拱腰处应变量相对前两者稍小。(2)在隧道横剖面上,随着围岩距洞室的距离增大,隧洞围岩的应变量呈对数关系递减。隧道围岩的变形主要发生在1倍洞径范围之内,超过2倍洞径后其变形量很小。(3)锚杆支护可有效减小围岩的应变量大小,但不能改变隧道开挖后围岩应力重新分布的特征。二、通过双洞对比试验,比较了毛洞状态和锚杆支护状态下围岩变形量的不同,得出了施加锚杆支护能减少约25%围岩变形的结论。说明实际施工时采用预订的锚杆支护方案能起到较好的支护效果。三、根据模型试验所总结的围岩变形规律,分析了华坪隧道施工中相关支护措施的有效性和合理性,并给出了合适的建议。四、通过数值模拟的方法分析了华坪隧道开挖后围岩的应力状态和位移情况,并将其与相似模型试验中所得结论进行互相对比验证。五、将华坪隧道现场位移监测数据与相似模型试验相关数据进行对比,验证了相似模型试验的可靠性与准确性。本次论文的结论对华坪隧道,乃至其他昔格达地层中的隧道设计和施工,有很好的参考价值。
[Abstract]:Xigeda formation is a special set of semi-diagenetic strata, its engineering properties are generally between extremely soft rock and soil. In view of its poor engineering properties, no railway or highway tunnel has been built in the Xigeda formation in the past. Therefore, the construction of highway tunnel in Xigeda formation is a new subject, and it is worth studying and exploring. Based on Huaping Tunnel of Lifan Expressway, the stability of surrounding rock of Xigeda formation tunnel is studied by using similar model test method. In this study, the engineering geological background of the tunnel is grasped in detail by collecting the relevant documents of Huaping Tunnel and combining with the field geological survey. Next, the relevant physical and mechanical parameters of surrounding rock of tunnel are obtained by indoor geotechnical test. After completing the preparatory work above, similar model tests were carried out, and the following main research results were obtained: first, through the excavation simulation of the Huaping tunnel and monitoring of the strain situation of the surrounding rock in all directions of the tunnel at the same time, The deformation law of surrounding rock after tunnel excavation is obtained. (1) after tunnel excavation, the strain of surrounding rock is the largest at the arch top, the second is the arch foot, and the strain at the arch waist is slightly smaller than the former two. (2) in the tunnel cross section, with the increase of the distance from the surrounding rock to the tunnel chamber, The strain of tunnel surrounding rock decreases in logarithmic relation. The deformation of the surrounding rock occurs mainly in the range of 1 times the diameter of the tunnel, and the deformation is very small after the tunnel exceeds 2 times diameter. (3) Anchor support can effectively reduce the size of the strain of surrounding rock, but it can not change the characteristics of stress redistribution of surrounding rock after excavation. Secondly, through the contrast test of two holes, the paper compares the deformation of surrounding rock under the condition of wool hole and bolt support, and draws the conclusion that applying bolt support can reduce the deformation of surrounding rock by about 25%. It shows that the bolt supporting scheme can play a better supporting effect in actual construction. Thirdly, according to the deformation law of surrounding rock summarized by model test, the validity and rationality of relevant supporting measures in the construction of Huaping tunnel are analyzed, and appropriate suggestions are given. Fourthly, the stress state and displacement of surrounding rock after excavation of Huaping tunnel are analyzed by numerical simulation, and the results are compared with those obtained in similar model tests. Fifthly, the field displacement monitoring data of Huaping Tunnel are compared with the related data of similar model test, and the reliability and accuracy of the similar model test are verified. The conclusion of this paper has good reference value for the design and construction of Huaping Tunnel and other tunnels in Xigeda formation.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U451.2

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