武深高速公路小方山隧道施工围岩—结构稳定性分析研究

发布时间：2018-03-26 02:07

  本文选题：浅埋偏压　切入点：小间距　出处：《重庆交通大学》2015年硕士论文

【摘要】：本文以武深高速公路小方山隧道为依托,以高速公路隧道围岩一结构稳定性分析为主线,以指导和提升小方山隧道的优化设计及安全施工为目的,分别运用定量评价、定性评价、整体评价以及局部评价相辅相成的方法,对小方山隧道围岩一结构的整体稳定性进行系统的分析。主要有以下几点内容:①荷载作为围岩—结构稳定的一项重要指标,本文结合公路隧道规范中浅埋隧道和偏压隧道的荷载计算原理与公式,经过分析推导后得到浅埋偏压同时存在情况下小间距隧道的荷载计算方法。在推导的计算公式基础上深入浅出地得到小间距隧道仅在浅埋情况下的荷载计算公式。②运用同济曙光软件模拟了小方山隧道的施工全过程。采取了先左洞后右洞和先右洞后左洞这两种施工次序的上下台阶法施工,分别得到了这两种施工次序的围岩以及支护结构的受力及变形情况,通过对比得到在浅埋偏压段宜选择先开挖右洞更利于工程的安全施工。同样对浅埋非偏压段进行了数值模拟,得到了围岩与支护结构的受力位移等情况。将其结果与浅埋偏压段的对比,得到了偏压情况下,无论是围岩最大主应力、围岩屈服区范围深度以及支护结构受力情况都偏向于深埋一侧较大,即出现左侧(深埋侧)大于右侧、左洞大于右洞的情况。而在浅埋非偏压情况下,左右洞的围岩及支护结构的受力和变形大致处于对称分布。③使用上下台阶法和全断面法两种不同的施工方法对深埋段Ⅳ级围岩进行数值模拟分析,分别得到了两种施工方法的围岩与支护结构在各施工步的应力及变形情况,得到的结果是在围岩性质不太好的Ⅴ级及Ⅳ级围岩宜选取台阶法施工,在围岩好的Ⅳ级和Ⅲ级围岩中可选择全断面法施工。而此深埋段Ⅳ级围岩处宜采取台阶法施工。④讨论分析了应力释放系数对二衬的影响。采取施作二衬时不同的围岩应力释放系数建模分析后比较其内力与变形,得到了在释放系数不断加大,围岩的拱顶竖向位移和拱腰水平相对位移均在减小,二衬拱顶和拱腰处轴力一直增大,二衬弯矩和剪力先增大然后在释放系数达到20%以后趋于稳定。这为现场施作二衬时间做出参考,也能对相似工程有所参考意义。
[Abstract]:Based on the Xiaofangshan Tunnel of Wu-Shen Expressway, the main line of this paper is the stability analysis of the surrounding rock structure of the expressway tunnel, with the aim of guiding and promoting the optimization design and safe construction of the Xiaofangshan Tunnel, the quantitative evaluation is used respectively. Qualitative evaluation, integral evaluation and local evaluation complement each other to systematically analyze the overall stability of the surrounding rock structure of Xiaofangshan Tunnel. The main contents are as follows: 1 load as an important index of the stability of the surrounding rock structure. This paper combines the principle and formula of load calculation of shallow tunnel and bias tunnel in highway tunnel code. After the analysis and deduction, the load calculation method of the tunnel with small spacing in the presence of shallow bias voltage is obtained. Based on the derived calculation formula, the load calculation formula of the tunnel with small spacing is obtained only in the case of shallow burying. Using Tongji dawning software, the whole construction process of Xiaofangshan Tunnel is simulated. The upper and lower step method is used to construct the first left hole then the right hole and the first right hole after the left hole. The stress and deformation of the surrounding rock and the supporting structure in these two construction sequences are obtained respectively. By comparison, it is concluded that the right hole should be excavated first in the shallow burying bias section is more beneficial to the safe construction of the project. The numerical simulation of the shallow burying unbiased section is also carried out. The stress displacement of surrounding rock and supporting structure is obtained. The results are compared with those of shallow burying section, and the maximum principal stress of surrounding rock is obtained under the condition of bias. The depth of the yield zone of surrounding rock and the stress of the supporting structure tend to be larger in the deep buried side, that is, the left side (deep buried side) is larger than the right side, and the left hole is larger than the right hole. The stress and deformation of surrounding rock and supporting structure of left and right cavern are approximately symmetrical distribution .3 numerical simulation analysis of deep buried section 鈪，

本文编号：1665860