河里煤矿立槽煤层开采覆岩破坏及地表移动变形研究.pdf

分类号 TD823.2 密级 编号 212012462 桂林理工大学 硕硕 士士 研研 究究 生生 学学 位位 论论 文文 （专（专 业业 学学 位）位） 河里煤矿立槽煤层河里煤矿立槽煤层开采开采覆岩破坏覆岩破坏 及地表移动变形研究及地表移动变形研究 学位类别学位类别 工程硕士 研研 究究 生生 田月明 学学 号号 212012462 工程领域工程领域 水利工程 研究方向研究方向 地下水科学与工程 导导 师师 郭纯青 职职 称称 教授 论文起止日期论文起止日期20122012 年年 9 9 月至月至 20142014 年年 4 4 月月 万方数据 Study on overburden strata failure and surface movement deation of mining vertical coal seams in Heli Mine MajorHydraulic Engineering Direction of StudyGroundwater Science and Engineering Graduate Student Yueming Tian Supervisor Prof. Chunqing Guo College of Environmental Science and Engineering Guilin University of Technology September,2012 to April,2014 万方数据 万方数据 I 摘 要 随着中国社会经济的持续快速发展，对煤炭的需求呈现出供不应求的局面。中国煤 炭资源分布虽然较广泛，但煤炭的赋存条件却千差万别，面对日益突显的资源缺口，急 倾斜煤层的开采逐渐引起人们的重视。 通常， 生产部门根据煤层的赋存条件及开采特点， 习惯上把倾角 90左右的急倾斜煤层称为立槽煤。 由于地质构造更为复杂， 立槽煤层开 采条件往往较困难，采动结束后的覆岩破坏形态及地表移动变形特征也与普通的急倾斜 煤层有所不同。 河里煤矿位于广西中部的合山市，矿区内煤层倾角多在 75 ～85 之间，属于典型的 立槽煤层。本文选取河里矿区作为研究区，在详细调查研究区地质条件及采煤现状的基 础上，合理概化相关地层岩性，构建立槽煤三维数值计算模型，模拟并分析不同因素影 响下的立槽煤层开采覆岩破坏及地表移动变形情况。此外，进一步应用概率积分法计算 特定开采工况下的地表移动变形量，结合相应数值模拟结果进行对比验证，并由此综合 确定研究区立槽煤层开采地表移动变形特征。 研究区立槽煤层开采经三维数值模拟及概率积分计算，得到以下主要结论 （1）受支承压力的影响，在工作面的边界煤柱及上下方岩层形成两个压应力集中 区；采空区上部覆岩因悬露而受拉应力作用明显，表现出在煤柱底部至煤柱下垂高 20m 的覆岩法向范围内形成一个拉应力集中区。 （2）采空区顶部和中下部覆岩形成两个剪切破坏区，覆岩沿层面发生剪切滑移破 坏，且破坏沿法线向上传递至地表进而引起地面移动下沉；采空区上部覆岩形成以拉张 破坏为主的拉剪混合破坏区，覆岩所受拉应力因超过岩石极限强度，发生断裂而冒落。 （3）覆岩变形呈拱状，越靠近采空区变形越大，且沿层面法向逐步扩展至地表。 当煤柱全回采时，覆岩因失去支承而发生大面积倾倒变形。覆岩最大变形位于采空区中 下部。覆岩变形量在煤柱全回采时达到最大，覆岩最大变形量为 697.7mm。 （4）工作面采动结束后，地表沉降呈现出一个不对称的瓢形沉陷区，下山方向地 表沉降变化缓，影响范围大，沉降边界可达数百米远；上山方向地表沉降变化陡，影响 范围较小，沉降边界达到底板一侧，沉陷区向采空区下山方向偏移。当煤柱垂高较小或 煤柱全回采时，地表沉降呈现出一个类似兜形的塌陷区，塌陷范围从底板一侧的地表延 伸至顶板一侧约 200m-250m 的区域，塌陷形态陡而深，沉降变化急且沉降量大。地表 沉降量在煤柱全回采时达到最大，地表最大沉降量为 590.2mm。 （5）地表水平移动量和影响范围在采空区下山方向大于上山方向，最大水平移动 点位于采空区下山方向一侧。地表水平移动量在煤柱全回采时达到最大，地表最大水平 移动量为 376.3mm。 万方数据 II （6）特定开采工况下，应用概率积分法计算的地表移动变形量与相应的数值模拟 结果较接近，表明在缺乏地表沉降实测资料的情况下，可运用这两种计算方法相互对比 验证，其综合结果能够基本反映研究区立槽煤层开采地表移动变形特征，与实际情况应 相符。 关键词关键词立槽煤层，覆岩破坏，地表移动变形，FLAC3D，概率积分法 万方数据 III Abstract With the rapid development of Chinese society and economy, the demand for coal is in short supply situation. Although coal resources distribute widely in China, the occurrence conditions of coal are in vastly different. Faced with the increasingly shortage of coal resources, steeply seam mining gradually have attracted peoples attention. Generally, according to the occurrence conditions and mining features, production departments are accustomed to call vertical coal that angle of coal seam is about 90 . Due to the complex geological structure, vertical coal mining is usually more difficult. The overburden strata failure and surface movement deation of vertical coal are different from common steeply inclined coal after mining. Heli mine locates in Heshan City, the central of Guangxi. the angles of coal seam in it are between 75 ～85 , which are typical vertical coal. This paper selects Heli mine as study area, surveying the geological conditions and the status of coal mining, generalizing the related lithology and establishing three-dimensional numerical model of vertical coal. Then the paper simulates and analyzes the overburden strata failure and surface movement deation of different factors. In addition, it further applies probability integral and calculates amount of surface movement deation with specific mining condition. Finally, it comprehensive determine the characteristics of surface movement deation, combining with the corresponding numerical result. After three-dimensional numerical simulation and probability integral calculation in vertical coal seams mining, we can conclude as follow 1 Affected by the supporting pressure, there are two compressive stress concentration area ing on the boundary pillar and strata. And due to hanging, the overburden strata upper gob is affected by tension seriously，ing a tensile stress area on overburden strata， which is from the bottom of pillar to 20m vertical height below. 2There are two shear failure zones ing on the top and lower part of gob’s overburden strata, it slippages and shears along the dimension, the shear failure passes to the surface and causes ground movement and subsidence. There is a tension-shear failure zone ing on the overburden strata upper gob. Due to exceeding the ultimate strength of rock, the overburden strata splits and falls down. 3 Overburden strata’s deation is vaulted. The amount of deation is greater close to the gob and extending to the surface along dimension. When the whole pillar is mined, 万方数据 IV overburden strata occurs large deation dumping according to lack of support. The maximum deation of overburden strata locates at the lower part of gob, which is 697.7mm with the whole pillar mined. 4After mining, the surface subsidence shows an asymmetrical scoop-shape，that changes slowly at bottom of gob with wide scope, and the border reaches several hundred meters. Otherwise, the surface subsidence changes steeply at top of gob with narrow scope, and the border reaches at bottom plate. When vertical height of pillar is small or the whole pillar mined is mined, the surface subsidence shows an pocket-shape, that ranges from the bottom plate to the top plate about 200m-250m. the appearance of surface subsidence is steep and deep. The maximum amount of surface subsidence is 590.2mm with the whole pillar mined. 5The amount and scope of surface’s horizontal movement at bottom is larger than at top, and the maximum movement point locates at bottom side of the gob, which is 376.3mm with the whole pillar mined. 6 In a specific mining condition, the result of probability integral calculation is close to three-dimensional numerical simulation. It indicates that applying the both s can basically reflect the characteristics of surface movement deation, without measured data of surface subsidence. Keywords vertical coal seams, overburden strata failure, surface movement deation, FLAC3D, probability integral 万方数据 V 目目 录录 摘摘 要要 .............................................................................................................................. I ABSTRACT ............................................................................................................... III 第第 1 章章 引言引言 ..................................................................................................................1 1.1 研究背景及意义...................................................................................................1 1.2 国内外研究现状及发展趋势 ...............................................................................1 1.2.1 国外研究现状 ................................................................................................2 1.2.2 国内研究现状 ................................................................................................3 1.3 研究目标、内容及技术方案 ...............................................................................5 1.3.1 研究目标 .......................................................................................................5 1.3.2 研究内容 .......................................................................................................5 1.3.3 技术方案与路线 ............................................................................................6 1.4 拟解决的关键问题、创新点 ...............................................................................7 1.4.1 拟解决的关键问题 .........................................................................................7 1.4.2 创新点 ...........................................................................................................7 1.5 可行性分析 ..........................................................................................................8 1.6 论文资料来源 ......................................................................................................8 1.7 小结 ......................................................................................................................9 第第 2 章章 自然地理概况及地质条件自然地理概况及地质条件 ............................................................................. 10 2.1 研究区自然地理概况 ......................................................................................... 10 2.1.1 地理位置及交通概况 .................................................................................. 10 2.1.2 气象水文 ..................................................................................................... 10 2.1.3 地形地貌 ..................................................................................................... 11 2.2 研究区地质条件................................................................................................. 11 2.2.1 地层岩性 ..................................................................................................... 11 2.2.2 含煤地层 ..................................................................................................... 12 2.2.3 地质构造 ..................................................................................................... 13 2.3 研究区水文地质条件 ......................................................................................... 15 2.3.1 含（隔）水岩组及地下水类型 ................................................................... 15 2.3.2 地下水的补给、迳流、排泄条件 ............................................................... 16 2.3.3 地下水动态特征 .......................................................................................... 16 2.4 柳花岭矿区基本概况 ......................................................................................... 16 万方数据 VI 2.5 小结 .................................................................................................................... 18 第第 3 章章 基于数值模拟求取岩体力学参数基于数值模拟求取岩体力学参数 .................................................................. 19 3.1 研究区岩体力学参数确定思路 ......................................................................... 19 3.2 岩体力学参数应用可行性分析 ......................................................................... 20 3.3 数值模拟软件的应用 ......................................................................................... 21 3.3.1 FLAC3D软件简介 ......................................................................................... 21 3.3.2 FLAC3D计算基本原理 ................................................................................. 21 3.3.3 FLAC3D求解流程及注意事项...................................................................... 22 3.4 柳花岭矿区 504 工作面岩体力学参数反演 ...................................................... 23 3.4.1 504 工作面工程概况 .................................................................................... 23 3.4.2 地层概化 ..................................................................................................... 24 3.4.3 模型构建及边界条件设置 .......................................................................... 25 3.4.4 计算准则及力学参数选取 .......................................................................... 25 3.4.5 地表沉降拟合及岩体力学参数修正 ........................................................... 26 3.5 小结 .................................................................................................................... 28 第第 4 章章 立槽煤三维数值计算模型的构建立槽煤三维数值计算模型的构建 .................................................................. 29 4.1 研究区樟村矿井基本工程概况 ......................................................................... 29 4.2 立槽煤层开采数值模拟研究方案 ...................................................................... 30 4.3 立槽煤三维数值计算模型的构建 ...................................................................... 31 4.3.1 模型建立及边界条件设置 .......................................................................... 31 4.3.2 计算准则及力学参数选取 .......................................................................... 33 4.3.3 立槽煤层开采方案 ...................................................................................... 33 4.3.4 监测点布置.................................................................................................. 34 4.4 小结 .................................................................................................................... 35 第第 5 章章 立槽煤层开采覆岩变形破坏数值模拟分析立槽煤层开采覆岩变形破坏数值模拟分析 .................................................. 36 5.1 煤层倾角对覆岩变形破坏的影响分析 .............................................................. 36 5.1.1 覆岩垂直应力分析 ...................................................................................... 36 5.1.2 覆岩塑性区分析 .......................................................................................... 40 5.1.3 覆岩变形分析 .............................................................................................. 42 5.2 覆盖层厚度对覆岩变形破坏的影响分析 .......................................................... 43 5.2.1 覆岩垂直应力分析 ...................................................................................... 44 5.2.2 覆岩塑性区分析 .......................................................................................... 47 5.2.3 覆岩变形分析 .............................................................................................. 49 万方数据 VII 5.3 煤柱垂高对覆岩变形破坏的影响分析 .............................................................. 50 5.3.1 覆岩垂直应力分析 ...................................................................................... 51 5.3.2 覆岩塑性区分析 .......................................................................................... 54 5.3.3 覆岩变形分析 .............................................................................................. 56 5.4 煤柱回采方式对覆岩变形破坏的影响分析 ...................................................... 57 5.4.1 覆岩垂直应力分析 ...................................................................................... 58 5.4.2 覆岩塑性区分析 .......................................................................................... 61 5.4.3 覆岩变形分析 .............................................................................................. 62 5.5 覆岩变形破坏综合分析...................................................................................... 64 5.6 小结 .................................................................................................................... 66 第第 6 章章 立槽煤层开采地表移动变形研究立槽煤层开采地表移动变形研究 .................................................................. 67 6.1 立槽煤层开采地表移动变形数值模拟分析 ...................................................... 67 6.1.1 煤层倾角对地表移动变形的影响分析 ....................................................... 67 6.1.2 覆盖层厚度对地表移动变形的影响分析 ................................................... 69 6.1.3 煤柱垂高对地表移动变形的影响分析 ....................................................... 70 6.1.4 煤柱回采方式对地表移动变形的影响分析................................................ 71 6.1.5 地表移动变形综合分析 .............................................................................. 72 6.2 立槽煤层开采地表移动变形的理论计算 .......................................................... 74 6.2.1 概率积分法的基本原理 ..................................................