单煤层采空区公路隧道施工力学行为研究

发布时间：2019-03-20 13:22

【摘要】：近年来,随着我国交通道路建设的迅速发展,可利用的土地资源逐渐减少,对道路选线的要求越来越高,公路隧道不可避免穿越采空区地层。在既有采空区的基础上修建公路隧道将会重新改变地层的应力场分布,对采空区地段的围岩稳定性造成严重影响,尤其是在采空区与隧道交汇地段,地应力场的分布异常复杂,对公路隧道产生不可忽视和潜在的危害,从而如何保证在采空区地层中隧道安全施工是一个亟待解决的问题。对穿越采空区地层隧道施工力学行为展开研究显得很有必要,且具有重要的工程意义。以宜(宾)-泸(州)高速公路观斗山隧道工程为研究背景,采用室内相似模型试验和数值模拟分析相结合的研究手段对跨度约12.5m的双向四车道高速公路采空区隧道施工力学行为进行了系统的研究。主要研究成果如下： 1、提出了上覆采空区隧道和下伏采空区隧道在横断面内和纵向上隧道开挖的安全间距； 2、基于平面应变假定,二维数值分析了下穿(或下伏)采空区时横断面内采空区对隧道施工引起的洞周位移、围岩应力、洞周锚杆轴力以及初期支护内力(弯矩和轴力)的影响规律以及施工扰动对采空区地层移动的影响规律； 3、室内相似模拟分析了在不同开挖支护下隧道施工对采空区地层移动的影响以及采空区的存在对初期支护受力特征的影响； 4、进行了隧道穿越采空区地层三维数值分析,研究了在纵向上采空区对洞周位移、洞周围岩应力、洞周锚杆轴力以及初期支护内力的影响规律以及施工扰动对采空区地层移动的影响规律。
[Abstract]:In recent years, with the rapid development of traffic road construction in China, the available land resources are gradually reduced, and the demand for road route selection becomes higher and higher. Highway tunnels inevitably traverse the goaf strata. The construction of the highway tunnel on the basis of the existing goaf will change the distribution of the stress field in the strata, which will seriously affect the stability of the surrounding rock in the goaf, especially in the intersection of the goaf and the tunnel, the distribution of the in-situ stress field will be very complex. It can not be ignored and potential harm to highway tunnel, so how to ensure the safe construction of tunnel in goaf stratum is an urgent problem to be solved. It is necessary and important to study the mechanical behavior of tunnel construction through goaf. Taking Guandoushan tunnel project of Yibin-Lu (state) highway as the research background, The mechanical behavior of goaf tunnel construction of two-way four-lane expressway with a span of about 12.5 m has been systematically studied by means of indoor similar model test and numerical simulation analysis. The main research results are as follows: 1. The safe spacing of tunnel excavation between overlying goaf tunnel and underground goaf tunnel in cross-section and longitudinal direction is put forward. 2. Based on the assumption of plane strain, the displacement around the tunnel and the stress of surrounding rock caused by the goaf in the cross-section of the cross-sectional goaf under the condition of the plane strain assumption are analyzed by two-dimensional numerical method. The influence law of bolt axial force and initial supporting internal force (bending moment and axial force) and the influence of construction disturbance on strata movement in goaf; 3. The influence of tunnel construction on the strata movement of goaf under different excavation and support and the influence of goaf on the force characteristics of initial support are simulated and analyzed in the laboratory. 4. The 3-D numerical analysis of the strata passing through the goaf is carried out, and the displacement of the goaf around the tunnel and the stress of the surrounding rock around the tunnel are studied in this paper. The influence law of bolt axial force and initial support internal force around the tunnel and the influence of construction disturbance on the strata movement in goaf.
【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】：U451;U455.49

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