南水北调中线一期工程郭村煤矿采空区段稳定性研究

发布时间：2018-03-13 23:30

本文选题：南水北调　切入点：采空区　出处：《华北水利水电大学》2015年硕士论文　论文类型：学位论文

【摘要】：采空区的稳定性问题是南水北调中线一期工程总干渠禹州段的重大工程技术问题之一。影响采空区稳定的因素十分复杂,渠道施工、运行及运行期内渠道的渗漏会导致采空区的进一步变形,进而威胁渠道的安全运行。本文首先介绍了国内外采空区稳定性研究现状及残余沉降预测已有成果,总结了采空区覆岩移动的基本形式,在详细介绍郭村煤矿采空区形成历史和处理措施的基础上,运用定性法、解析法、监测法和数值法对南水北调郭村矿采空区段的稳定性、残余变形和渗漏工况下的稳定性展开以下研究工作:(1)结合各行业对采空区的研究成果,归纳影响南水北调下伏采空区稳定性的主要因素有采矿和顶板管理方法、上覆岩体的力学特性、煤层赋存条件和开采时间;郭村煤矿采空区处于残余变形期,基本处于稳定状态,但由于采煤方法和顶板管理方法的落后及渠道施工运行的影响,潜在残余变形较大。(2)基于概率积分法沉陷理论,推导出采空区在自重下残余变形极限值计算公式,计算郭村煤矿采空区竖直残余变形极限值为331mm,水平残余变形极限值为82.8mm。以郭村煤矿采空区剖面4为基础,应用FLAC3D软件建立数值模型,模拟采空区无注浆处理工况下渠道施工与运行过程来研究其变形规律。结果显示,水平位移最大值位于采空区两端上方地表,其值较小;竖直位移最大值为9.32cm,地表竖直位移随采空区埋深增大而减小,随离渠道水平距离增大而减小;渠道运行对地表变形影响有限。(3)分析渠道施工期间地表沉降监测数据,结果显示:施工前,采空区残余变形小,基本稳定;注浆和开挖施工导致采空区残余变形较施工前增大,但注浆明显有减缓变形的作用,工程场区地表变形值总量较小,整体较稳定。(4)应用FLAC3D建立郭村煤矿采空区段三维模型,通过对地层Q3和Q2在不同含水率下力学参数的弱化来模拟渠道运行期无渗漏、一般渗漏和严重渗漏三种工况,结果显示,采空区注浆区地表沉降值比无处理区小1-2cm,注浆可明显减小残余变形;竖向位移主要分布于地层Q3和Q2中,其最大值、影响范围和深度均随着渗漏程度增大而增大,初期引起的地表沉降增量比后期增量大,竖向位移最大为5.46cm,而围岩和采空区中基本无竖向变形;在渠底,差异沉降明显,严重渗漏工况下差异沉降最大值为4.2cm,倾斜为2-3mm/m,可导致渠底混凝土板拉裂破坏;水平位移最大值为1.24cm,影响相对较小。
[Abstract]:The stability of goaf is one of the major technical problems in Yuzhou section of the main trunk canal of the first stage of South-to-North Water transfer Project. The factors affecting the stability of the goaf are very complicated, and the canal construction, The leakage of the canal during operation and operation will lead to further deformation of goaf and threaten the safe operation of the channel. This paper first introduces the present situation of research on the stability of goaf and the existing achievements in prediction of residual settlement at home and abroad. The paper summarizes the basic forms of overlying rock movement in goaf, and on the basis of introducing in detail the formation history and treatment measures of goaf in Guocun Coal Mine, applies qualitative method, analytical method, monitoring method and numerical method to the stability of goaf section of Guocun Mine of South-to-North Water transfer. Under the condition of residual deformation and leakage, the following research work is carried out: 1) combined with the research results of various industries on the goaf, the main factors affecting the stability of the goaf under the South-to-North Water diversion Project are the mining and roof management methods. The mechanical characteristics of overlying rock mass, coal seam occurrence condition and mining time, the goaf of Guocun coal mine is in the period of residual deformation and is basically in a stable state, but due to the backwardness of coal mining method and roof management method and the influence of canal construction operation, Based on the theory of probability integration, the formula for calculating the limit value of residual deformation in goaf under self-weight is derived. The vertical residual deformation limit value of goaf in Guocun coal mine is 331mm and the horizontal residual deformation limit value is 82.8mm. based on section 4 of goaf of Guocun coal mine, a numerical model is established by using FLAC3D software. Under the condition of no grouting treatment in goaf, the process of canal construction and operation is simulated to study its deformation law. The results show that the maximum horizontal displacement is located on the surface above the two ends of goaf, and its value is small. The maximum vertical displacement is 9.32 cm, the surface vertical displacement decreases with the increase of the buried depth of goaf and decreases with the increase of horizontal distance from the canal, and the influence of channel operation on surface deformation is limited. The results show that the residual deformation of goaf is small and stable before construction, the residual deformation of goaf caused by grouting and excavation is larger than that before construction, but grouting can obviously slow down the deformation, and the total amount of surface deformation in engineering site is small. Using FLAC3D to establish 3D model of goaf section in Guocun Coal Mine. By weakening the mechanical parameters of formation Q3 and Q2 under different water content, three working conditions of no leakage, general leakage and serious leakage are simulated. The results show that, The surface subsidence value in goaf grouting area is 1 ~ 2 cm smaller than that in no treatment area, grouting can obviously reduce residual deformation, vertical displacement mainly distributes in stratum Q _ 3 and Q _ 2, and its maximum value, influence range and depth increase with the increase of leakage degree. The increment of surface subsidence caused by the initial stage is larger than that of the later period, and the maximum vertical displacement is 5.46 cm, but there is no vertical deformation in the surrounding rock and goaf, and the differential settlement is obvious in the bottom of the canal. The maximum value of differential settlement is 4.2 cm and the inclination is 2 ~ 3 mm / m, which can lead to tensile failure of concrete slabs at the bottom of the canal, and the maximum value of horizontal displacement is 1.24 cm, the influence is relatively small.
【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD325.3

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