近距离煤层回采巷道过上覆采空区及煤柱支护技术研究.pdf

万方数据 万方数据 太原理工大学硕士研究生学位论文 I 近距离煤层回采巷道过上覆采空区及煤柱支护技术研究 摘摘 要要 随着煤炭资源的不断开采，开采条件较好的煤层逐渐开采殆尽，难采 煤炭资源的开采越来越受到各大煤矿的重视，其中近距离煤层开采占了很 大比重。由于近距离煤层层间距近，开采不同煤层，相互之间会发生扰动， 层间岩层破碎严重，给下煤层开采带来很大困难，尤其当是下部煤层开采 遇到上煤层应力集中煤柱时，矿压显现明显。极近距离煤层的开采可以提 高煤炭资源的利用率，进而实现高产高效的目的。 本论文对近距离煤层回采巷道过上覆采空区及煤柱支护技术进行研究。 通过查阅相关文献资料分析了国内外研究现状，结合工程地质资料对采场 顶底板结构建立力学模型并进行理论分析计算，得出上煤层旧工作面底板 破坏深度，下工作面过上覆煤柱关键块破断规律及对下工作面回采巷道支 护的影响，尤其是出煤柱阶段，顶板容易出现整体垮落，巷道围岩超前破 坏严重，并通过 FLAC3D 数值计算软件对整个过程进行模拟得出在下工作 面在进出煤柱时矿压显现较为剧烈。针对下工作面有规律的交替通过上覆 采空区及煤柱，研究了巷道围岩破坏特征及应力变化规律，在煤柱下围岩 应力大，围岩容易破坏，在煤柱影响范围内巷道需要加强支护。就工作面 实际开采条件对下工作面两顺槽支护提出比选方案，通过数值模拟进行应 力应变分析，得出最终优化方案。将方案应用于以山西煤炭运销集团金达 煤业近距离煤层下工作面回采项目的工程实践中，并运用不同方法监测巷 道围岩变形量，分析巷道的支护效果。得到具体结论如下 （1）根据经验公式和滑移线场理论计算出底板破坏的最大深度，建立 煤柱上方关键层小结构力学模型并分析得出下煤层回采巷道在工作面采过 煤柱时的围压变化及围岩破坏的规律。回采巷道受工作面过上覆区段煤柱 万方数据 太原理工大学硕士研究生学位论文 II 影响较大，特别是在进出煤柱阶段，会受到工作面动载的影响。 （2）采空区下巷道受采空区卸压效应影响，围岩压力较小，巷道变形 量较小，可以充分发挥其自身稳定性，但受上工作面采动影响，顶板较为 破碎，支护困难。煤柱下巷道开掘后，受覆岩区煤柱应力集中现象影响， 垂直应力急剧增加，两肩岩体发生剪切破裂，剪切破坏范围增大，顶板下 沉量大，导致巷道变形和破坏严重。 （3）9煤回采后，其下的 1011煤层应力重新分布，出现明显的升高 和降低的区域，位于煤柱中心线下部的岩体的垂直应力最大，由中心线向 两侧延伸，围岩垂直应力逐渐减小。1011煤层工作面处在煤柱正下方及 其边界外侧 10m 以内的范围时两侧回采巷道受集中煤柱影响围岩破坏量增 大，超前工作面 15m 巷道顶板破坏严重。因此，在巷道经过上覆煤柱影响 区时，必须通过增加锚杆长度、缩小锚杆间排距以及补打锚索等措施对巷 道进行加强支护。 （4）结合理论分析、工程类比、数值模拟最终确定了 1011煤二采区 南翼回采巷道具体的锚杆与锚索的锚固方式与锚固参数，经现场实测，得 知所采取支护方案满足工程要求。 关键词近距离煤层；煤柱；巷道支护；FLAC3D 万方数据 太原理工大学硕士研究生学位论文 III STUDY ON THE SUPPORTING TECHNOLOGY OF CLOSE-MULTIPLE COAL SEAMS MINING ROADWAY PASSING THROUGH OVERBURDEN GOAFS AND COAL PILLARS ABSTRACT With the continuous exploitation of coal resources, coal seams with better mining conditions are gradually being mined, and the mining of difficult-to-find coal resources is increasingly valued by major coal mines, of which close-multiple coal seam mining accounts for a large proportion. Due to the close spacing of coal seams, the mining of different coal seams will cause disturbances between each other, and the strata will be broken severely, which will cause great difficulties for the exploitation of the lower coal seams, especially when the lower coal seams meet the coal seam stress concentration coal pillars. The mine pressure is obvious. The mining of close-multiple coal seam can improve the utilization of coal resources and achieve high production efficiency. In this thesis, the Supporting Technology of close-multiple Coal Seams Mining Roadway Passing through Overburden Goafs and Coal Pillars is studied. By reviewing the relevant literature data, the research status at home and abroad was analyzed, and the mechanical model of the top and bottom structure of the stope was established based on the engineering geological data. The theoretical analysis and calculation were conducted to obtain the depth of floor damage of the old working face of the upper coal seam. The lower working face was overlaid with coal pillars. The breaking rules of key blocks and their influence 万方数据 太原理工大学硕士研究生学位论文 IV on the support of the mining roadway in the lower face, especially in the stage of coming out coal pillars, the roof can be easily cut down, The surrounding rock of the roadway is seriously damaged ahead of working face. The whole process is simulated by the FLAC3D numerical calculation software. The working face is more intense in the stage in and out of the coal pillars. In view of the regular alternation of the lower face through overlying goafs and coal pillars, the characteristics of the surrounding rock failure in the roadway and the law of stress variation in the roadway surrounding rock are studied. Under the coal pillars, the surrounding rock stress is high and the surrounding rocks are easily destroyed. Roadways within the influence of pillars need to be reinforced. On the face of the working conditions of the actual mining conditions on the two-slotted support of the lower face of the proposed alternative program, through the numerical simulation of stress and strain analysis, the final optimization program. The scheme was applied to the engineering practice of Shanxi Coal Mining Groups Jinda Coal Mining Group working face mining project under extremely close coal seams, and using the field data monitored by different s to analyze the supporting effect of the roadway. The specific conclusions are as follows 1 According to the empirical ula and the slip line field theory to calculate the maximum depth of the floor damage, the establishment of the key structure of the small pillar above the pillar mechanical model and analysis of the lower coal seam mining lane in the face of the coal pillars when the confining pressure changes And the law of destruction of surrounding rocks. Mining lanes are affected by the coal pillars overlying the working face, especially during the entry and exit of the pillars, which are affected by the dynamic load of the working face. 万方数据 太原理工大学硕士研究生学位论文 V 2 Affected by the pressure relief effect of the goafs in the roadway below the goafs, the pressure of the surrounding rock is small and the deation of the roadway is small. It can give full play to its own stability, but due to the influence of mining on the top face, the roof is relatively broken. Support is difficult. After the underground roadway of coal pillars is excavated, the vertical stress increases sharply due to the stress concentration phenomenon of coal pillars in the covered rock area. Shear fractures occur in the two shoulder rock masses, the shear damage scope increases, and the amount of roof subsidence is large, leading to serious roadway deation and damage. 3 After 9 coal mining, the stress of the 1011 coal seam beneath it is redistributed, and there is a clear increase and decrease in the area. The vertical stress of the rock mass below the centerline of the coal pillar is the largest, from the centerline to the two. Lateral extension, the vertical stress of surrounding rock decreases gradually. When the 1011 coal seam face is located within the range of 10m directly below the coal pillar and outside of the boundary, the destruction of the surrounding rock is affected by the concentrated coal pillars on both sides of the mining lane, and the roof of the 15m roadway in the leading face is seriously damaged. Therefore, when the roadway passes through the pillar-affected zone, the roadway must be reinforced and supported by measures such as increasing the length of the bolt, reducing the spacing between the bolts, and supplementing the anchor cable. 4 Based on theoretical analysis, engineering analogy and numerical simulation, the anchoring and anchoring parameters of the anchor rod and anchor cable in the south wing of the 1011 coal mining area were finally determined. The support plan meets the engineering requirements. KEY WORDS close coal seam; pillar; roadway support; FLAC3D 万方数据 太原理工大学硕士研究生学位论文 VI 万方数据 太原理工大学硕士研究生学位论文 VII 目录 摘 要........................................................................................................................................I ABSTRACT..........................................................................................................................III 目录................................................................................................................................. VII 第一章绪论.............................................................................................................................1 1.1 论文研究背景及意义.......................................................................................................1 1.2 国内外研究现状...............................................................................................................1 1.2.1 近距离煤层上位煤层底板破坏规律研究现状........................................................1 1.2.2 近距离煤层过上覆煤柱巷道破坏规律研究现状....................................................2 1.2.3 近距离煤层巷道支护研究现状................................................................................4 1.3 存在的问题分析...............................................................................................................6 1.4 研究内容及技术路线.......................................................................................................7 1.4.1 研究内容....................................................................................................................7 1.4.2 技术路线图................................................................................................................7 第二章近距离煤层巷道围岩结构稳定性分析.....................................................................9 2.1 上煤层开采后围岩应力分布规律..................................................................................9 2.1.1 覆岩非充分垮落时围岩应力分布...........................................................................9 2.1.2 覆岩充分垮落时围岩应力分布.............................................................................10 2.1.3 上煤层开采底板破坏深度分析.............................................................................10 2.2 回采巷道受工作面过上覆区段煤柱的影响................................................................12 2.2.1 采空区老顶岩层断裂在区段煤柱上形成的小结构.............................................13 2.2.2 进煤柱阶段巷道稳定性分析.................................................................................15 2.2.3 过煤柱阶段巷道稳定性分析.................................................................................16 2.2.4 出煤柱阶段巷道破坏机理分析.............................................................................17 2.3 下煤层巷道应力分布规律.............................................................................................18 万方数据 太原理工大学硕士研究生学位论文 VIII 2.3.1 上煤层底板采动应力计算.....................................................................................18 2.3.2 煤柱下巷道围岩破坏特征......................................................................................22 2.3.3 采空区下巷道围岩破坏特征..................................................................................25 2.4 本章小结.........................................................................................................................28 第三章回采巷道受工作面过上覆煤柱影响数值模拟研究...............................................31 3.1 巷道支护参数及模型建立.............................................................................................31 3.1.1 金达煤业二采区南翼工作面地质特征..................................................................31 3.1.2 模型建立..................................................................................................................36 3.2 模拟过程及结果分析.....................................................................................................37 3.2.1 模拟过程..................................................................................................................37 3.2.2 上覆煤柱稳定性及其对下部岩层影响..................................................................37 3.2.3 下煤层回采巷道受工作面过煤柱时顶底板应力应变分布规律研究..................38 3.3 本章小结.........................................................................................................................41 第四章金达煤业近距离煤层回采巷道支护数值模拟研究...............................................43 4.1 巷道支护设计原则.........................................................................................................43 4.2 工作面顺槽的数值模拟方案.........................................................................................44 4.3 支护效果数值模拟分析.................................................................................................45 4.3.1 运输顺槽支护效果数值模拟分析.........................................................................45 4.3.2 回风顺槽支护效果数值模拟分析.........................................................................50 4.4 支护方式与支护参数的设计与施工.............................................................................61 4.4.1 工作面运输顺槽支护方案.....................................................................................61 4.4.2 工作面回风顺槽支护方案.....................................................................................62 4.5 本章小结.........................................................................................................................64 第五章围岩动态监测...........................................................................................................65 5.1 测点布置........................................................................................................................65 万方数据 太原理工大学硕士研究生学位论文 IX 5.2 监测方法........................................................................................................................65 5.3 支护效果分析.................................................................................................................67 5.4 本章小结.........................................................................................................................70 第六章结论与展望...............................................................................................................71 6.1 主要结论.........................................................................................................................71 6.2 不足与展望.....................................................................................................................71 参考文献...................................................................................................................................73 致 谢.....................................................................................................................................77 附录 A攻读硕士学位期间发表的学术论文.......................................................................79 附录 B攻读硕士学位期间参与的科研项目.......................................................................79 万方数据 太原理工大学硕士研究生学位论文 X 万方数据 太原理工大学硕士研究生学位论文 1 第一章绪论 1.1 论文研究背景及意义 煤炭作为一种重要的工业原料，对国家经济社会发展起着举足轻重的作用[1]。我国 自 1995 起煤炭产量一直居世界第一位，我国能源消费量巨大，煤炭因其储量丰富，价 格低廉，被广泛的使用于电力，化工，冶金等各个行业，尽管煤炭在能源结构中比重在 下降，但仍然占据着主导地位[2]。因此，保证煤炭产能合理稳定会是今后较长一段时间 内的必然需要。由于在以往煤炭的开采中，大部分煤矿已经将开采条件好的煤层开采殆 尽，难采煤炭资源的开采的问题得到越来越多的重视，其中，近距离煤开采作为大多数 矿区存在的问题，占很大比重[3]。 地层内不同煤层间距离不尽相同，有的距离较远，有的间距较小，甚至交叉合并， 当煤层层间距较大时，上下煤层之间影响很小，开采时其矿压显现特征、开采方法与单 一煤层开采基本一致。但随着煤层间距缩小，上煤层的开采就会影响下煤层应力分布规 律，对下煤层顶板也会造成不同程度的破坏[4]。上煤层对下煤层的影响主要来自于采空 区内垮落的矸石破断岩层和遗留的区段煤柱，使得下煤层顶板受力不均，上覆煤柱下方 的巷道支护困难，巷道围岩移近量大，底臌量大；工作面容易导致压架，煤壁片帮严重； 上覆采空区下，顶板不稳定，容易冒落并沟通上部采空区，导致通风困难，而且常规的 锚杆支护不再适用[5,6]。由于近距离煤层开采有单一煤层理论无法解释的特殊性，因此 对其进行深入研究显得尤为重要。 1.2 国内外研究现状 1.2.1 近距离煤层上位煤层底板破坏规律研究现状 对于距离较近的两层煤，其中一层煤的开采必然会影响另一煤层的顶板或底板。对 近距离上煤层的开采将会破坏围岩原岩应力的分布状态， 并且所开采空间的围岩应力将 会重新分布[7]，导致上煤层遗留的区段煤柱上产生应力集中，并向其下底板深部传递。 上煤层的回采将会引起下部煤层顶板不同程度的损伤， 而且采空区下的煤层顶板结构也 将会发生改变[8]。开采所引起的底板所受荷载的分布发生了变化，进而煤层底板应力将 万方数据 太原理工大学硕士研究生学位论文 2 会重新分布。 近距离煤层在我国现行煤矿安全规程中的定义为煤层的层间距离很近，开采时 相互间具有显著影响的煤层。并没有给出准确的判断依据。张百胜教授最早从定量的角 度定义了近距离煤层，他认为划分近距离煤层的依据是当煤层间距 hj≤hσ时，hσ为上煤 层开采时采场底板岩层的损伤深度，该煤层群为近距离煤层，并给出了底板破坏深度计 算公式。并且他还将近距离下煤层顶板划分为三类即夹石假顶、碎裂顶板和块裂顶板， 构建了“块体-散体”顶板结构的模型，揭示了下煤层开采顶板冒落的动态过程[6]。 吴爱民等使用 DDA 数值模拟软件对钱家营煤矿近距离煤层群开采回采工作面的应 力场范围、上覆岩层的离层范围及其破坏程度进行了研究，得出了近距离煤层开采上覆 岩层的移动规律[9,10]。 郭文兵利用光弹性力学理论和相似模拟实验，对多煤层同采采场围岩应力分布特征 以及相互影响进行研究，得出了平煤集团八矿井田内采场围岩应力分布的规律、应力集 中程度及其相互之间的影响程度和范围[11]。 史元伟采用解析法和数值分析的知识研究了近距离煤层开采的相互影响和上覆煤柱 下方底板岩层应力分布特征，对下煤层开采时围岩的控制有重要指导意义[12,13]。 刘天泉通过综合强度理论和强度理论得出了底板受采动影响的最大破坏深度[14]。 李白英提出煤层底板自上向下存在三个带即采动破坏带、 完整岩层带和导升高度带， 即“下三带”理论，而且给出了底板破坏深度与采面斜长之间的线性关系，成为底板变形 理论研究的新突破[15,16]。 王作宇认为顶板自重应力场