近距离薄煤层群联合开采顶板破断机理研究.pdf

太原理工大学硕士研究生毕业论文 I 近距离薄煤层群联合开采顶板破断机理研究 摘 要 本文是以山西焦煤西山煤电集团公司官地煤矿 2 号、3 号煤层为工程背 景，运用理论计算、数值模拟和矿压观测等多种手段，对近距离薄煤层群 联合开采顶板破断机理做了深入分析，结论如下 （1）本文结合官地煤矿 2、3 号煤层间顶板条件，将近距离薄煤层层间 顶板按其岩性和节理裂隙发育情况分为 3 种，即不稳定层间顶板结构、 中等稳定层间顶板结构、稳定层间顶板结构。并根据这 3 种层间顶板结构， 将其破断形式分为 3 种，即不稳定层间顶板结构为散体破断，中等稳定层 间顶板结构为块体破断，稳定层间顶板结构为板式破断。 （2）分别分析了三种层间顶板结构在下煤层工作面回采过程中的顶板 破断机理，指出①不稳定层间顶板结构为散体破断，此种结构强度较小， 其层间直接顶会随着下煤层的开采而冒落，且冒落方式主要是散体块之间 的滑移，此种结构的矿压显现非常微弱；②中等稳定层间顶板结构为块体 破断，此种破断方式是以块体的垮落失稳为主，此种结构会有一定的矿压 显现，但不剧烈；③稳定层间顶板结构为板式破断，由于此种结构的层间 顶板比较完整，故将其看为一个薄板，且在工作面的回采过程中其层间顶 板表现为 O-X”型破断形式，由于此类层间顶板结构其直接顶岩层具有一定 的强度，会形成一定的支撑结构，形成周期来压现象，故其矿压显现比较 明显。 （3）根据薄板矿压理论，建立了不同开采过程中的四种不同的板结构 万方数据 太原理工大学硕士研究生毕业论文 II 支撑模型，并对其破断规律进行了数值求解。得出首采工作面直接顶初次 破断最是在长边和短边的中点处；首采工作面直接顶周期破断最是在长固 边的中点和短固边距离采空区 a 5 1 处； 接续工作面直接顶初次破断是在长固 边距离采空区b 5 1 和短固边的中点处；接续工作面直接顶周期破断是在长 固边距离采空区b 5 1 和短固边的 a 5 1 处。根据官地煤层 3318 工作面的工程 实际， 将各项数据带入公式计算后得出 3318 工作面初次来压步距为 21.4m， 周期来压步距为 19.8m。 （4）建立了上煤层单独开采时的数值模拟模型，通过对不同推进距离 的上煤层工作面顶板垮落情况和矿压显现情况分析，确定了上煤层开采时 其工作面上方直接顶岩层的顶初次断裂发生在工作面向前开采到 25m 时， 而周期断裂步距为 20m 左右。 （5）建立了三种不同顶板结构条件下的下煤层开采数值模拟模型。并 对其下煤层 3 号煤工作面在不同推进距离下的顶板下沉情况以及来压情况 进行了分析。得出①对于不稳定层间顶板结构，由于其层间直接顶为软 弱泥页岩且节理裂隙发育，再加上上煤层的采动影响，其直接顶变为非常 破碎的散体结构，在下煤层的开采过程中，这种散体结构的顶板几乎没有 任何支撑作用，表现为其顶板随着工作面的向前推进持续冒落，这也就解 释了这种层间顶板结构开采时矿压显现非常微弱的显现。②对于中等稳定 层间顶板结构，在下煤层的开采过程中，同不稳定层间顶板结构不一样， 此类顶板结构有一定的支撑能力，其直接顶垮落也不是随采随冒，而是相 对于工作面推进有一个 510m 的滞后距离。这正是说明了，此类顶板结构 万方数据 太原理工大学硕士研究生毕业论文 III 的各个块与块之间在工作面的回采过程中形成了相互支撑的情况，但由于 块体自身尺寸的限制，并不能形成长距离的支撑，所以才会出现 510m 的 滞后距离。③对于稳定层间顶板结构，在下煤层的开采过程中，其直接顶 中较坚硬的岩层形成类似于薄板的结构，故在开采过程中，能够出现初次 垮落、周期垮落的现象。在层间距为 8m，直接顶为 4m 厚较坚硬岩层的情 况下，经过上述分析可得出下煤层 3 号煤工作面直接顶的初次垮落步距为 2025m 内，下煤层 3 号煤工作面直接顶繁荣周期垮落步距为 20m 左右。 （6）通过官地煤矿提供的 3318 工作面数据，对 3318 工作面矿压数据 规律进行了分析。得出了 3318 工作面初次来压步距为 23.8m，3318 工作面 周期来压步距为 21.3m。这与前面的理论计算以及数值模拟的结果相吻合。 关键词顶板破断，薄板理论，数值模拟，矿压显现 万方数据 太原理工大学硕士研究生毕业论文 IV 万方数据 太原理工大学硕士研究生毕业论文 V STUDY ON FRACTURING MECHANISM OF STOPE ROOF DURING COMBINING MINING OF CLOSED THIN COAL SEAM GROUP ABSTRACT Based on the Guandi Coal Mine of Shanxi coking coal Xishan Coal Electricity Group Company No. 2 and No. 3 coal seam as the engineering background, through theoretical calculation, numerical simulation and observation and other means to close thin coal seam combined mining roof breaking mechanism are analyzed deeply. The conclusions are as follows 1According to Guandi mine No. 2 and No. 3 coal seam between the roof condition, close thin coal seam roof layer according to the lithology and joint fissures were divided into 3 types, namely the unstable layer between roof structure and roof structure, moderately stable interlayer stability between layers of roof structure. According to the 3 layer of roof structure, the breaking is divided into 3 kinds, namely the unstable layer of loose broken roof structure, moderately stable layer of roof structure for block breaking, stable layer of roof structure for slab breaking. 2Analysis of roof three kinds of roof structure layer in coal seam mining face in the process of breaking mechanism, pointed out that the unstable layer between the roof structure of loose broken, the structure strength is small, the 万方数据 太原理工大学硕士研究生毕业论文 VI layer will fall under the direct roof with coal mining and caving, and is the main way of slip dispersion between the blocks, the structure of the mine pressure appear very weak; the middle layer between the stability of roof structure for block broken, the broken way is to block the collapse and instability, the structure will have a certain pressure showing mine, but not severe; the stability of interlayer structure for the roof plate broken, because the structure of the interlayer roof is complete, so it is seen as a thin plate, and in the mining process in the layer of roof is O-X “broken s, such as the roof structure layer direct roof rock Layer has a certain strength, will a certain support structure, ing a cycle to pressure phenomenon, so its mine pressure is obvious. 3Based on the theory of sheet rock pressure, four different support models for plate structures in different mining processes are established, and their fracture laws are numerically solved. The first coal face direct roof first breaking is at the midpoint of the long side and a short side; the first coalface roof cycle breaking is the most in the center of long and short side of the solid solid edge distance goaf; continuous working face roof first breaking in long distance by solid edge empty area and short solid edge at the midpoint of the connection; face top cycle breaking in long distance goaf solid edge and short solid edge at. According to the engineering practice of the 3318 working face of Guandi Coal Seam, the data are brought into the ula calculation, and the initial pressure step distance of the 3318 working face is 21.4m, and the period to pressure step is 19.8m. 万方数据 太原理工大学硕士研究生毕业论文 VII 4Established on coal seam mining separate numerical simulation model of the roof caving and mining analysis of different pressure on coal seam distance, the roof fracture above the working face of direct roof rock on coal seam mining in the 25m working face before, and periodic weighting distance is about 20m. 5Three numerical simulation models of lower coal seam mining are set up under different roof structures. The subsidence of roof and the pressure of coal face in No. 3 coal seam under different pushing distance are analyzed. For the unstable layer roof structure, due to the weak interlayer of direct roof shale and joint fissures, and the influence of mining on the coal seam, the direct roof is very loose structure broken, in the process of coal seam mining under the roof, the granular structure almost without any support effect of perance for the roof with the working face advancing continuously falling, this also explains the layer structure of mining roof strata pressure appears very weak. For the moderate stability between layers of roof structure, in the process of coal seam mining under the same roof, unstable layer structure is not the same, the roof structure with support ability, the immediate roof caving is not with adopt withemit, but relative to promote a 510m working face after lag distance. This is explained, between this kind of roof structure all the blocks in the mining process in the ation of mutual support, but because of its block size limit, and not long distance support, so will the 510m lag distance. The stable layer of roof structure, in the process of mining coal seam, the direct roof is hard rock ation structure similar to that of thin plate, so in the mining process, can 万方数据 太原理工大学硕士研究生毕业论文 VIII appear the first caving, the phenomenon of periodic caving. In the layer distance, the immediate roof is thick hard rock conditions, through the above analysis can be obtained under the first coal seam working face No. 3 direct top caving step in coal seam No. 3 coal face top boom caving step around. 6 Based on the data of 3318 working face provided by Guandi Coal Mine, the law of rock pressure data at 3318 working face is analyzed. It is concluded that the first step pressure distance of 3318 working face is 23.8m, and that of 3318 working face is 21.3m. This is consistent with the previous theoretical calculations and numerical simulations. KEY WORDSroof breaking, thin plate theory, numerical simulation, strata development 万方数据 太原理工大学硕士研究生毕业论文 IX 目 录 摘 要 ........................................................................................................................................... I ABSTRACT .............................................................................................................................. V 目 录 ........................................................................................................................................ IX 第一章 绪 论 .......................................................................................................................... 1 1.1 本文研究背景及意义 ............................................................................................... 1 1.2 国内外研究现状 ....................................................................................................... 1 1.2.1 近距离煤层群定义 ........................................................................................ 1 1.2.2 采场顶板岩层理论研究现状 ........................................................................ 2 1.2.3 近距离薄煤层群联合开采研究现状 ............................................................ 6 1.3 主要研究内容 ........................................................................................................... 8 1.4 技术路线 ................................................................................................................... 9 第二章 近距离薄煤层群联合开采顶板结构力学模型 ........................................................ 9 2.1 矿井概况 ................................................................................................................. 11 2.1.1 矿区概况 ...................................................................................................... 11 2.1.2 2、3 号煤层情况 ......................................................................................... 11 2.2 层间顶板结构分类 ................................................................................................... 12 2.2.1 不稳定层间顶板散体破断 ............................................................................ 12 2.2.2 中等稳定层间顶板块体破断 ........................................................................ 12 2.2.3 稳定层间顶板板式破断 ................................................................................ 13 2.3 本章小结 ................................................................................................................... 14 第三章 层间顶板破断理论计算 ............................................................................................ 17 3.1 块体破断理论计算 .................................................................................................... 17 3.2 板式破断薄板模型的基本理论与求解 ................................................................... 18 3.2.1 薄板理论适用条件 ........................................................................................ 18 3.2.2 弹性薄板的基本微分方程 ............................................................................ 18 3.3 不同边界条件下板式破断的力学分析 ................................................................... 20 万方数据 太原理工大学硕士研究生毕业论文 X 3.3.1 首采工作面直接顶初次破断力学模型分析 ................................................ 20 3.3.2 首采工作面直接顶周期破断力学模型分析 ................................................ 23 3.3.3 接续工作面直接顶初次破断力学模型分析 ................................................ 25 3.3.4 接续工作面直接顶周期破断力学模型分析 ................................................ 27 3.4 层间顶板破断判据 ................................................................................................... 29 3.4.1 破断判据 ........................................................................................................ 29 3.4.2 实例计算 ........................................................................................................ 30 3.5 本章小结 ................................................................................................................... 30 第四章 近距离薄煤层群顶板破断数值模拟分析 ................................................................ 31 4.1 3DEC 模拟软件 ......................................................................................................... 31 4.2 模型的建立 ............................................................................................................... 31 4.3 上煤层开采顶板破断情况模拟 ............................................................................... 33 4.3.1 2 号煤层开采 15m 时顶板破断情况 ............................................................. 33 4.3.2 2 号煤层开采 20m 时顶板破断情况 ............................................................. 35 4.3.3 2 号煤层开采 25m 时顶板破断情况 ............................................................. 39 4.3.4 2 号煤层开采 45m 时顶板破断情况 ............................................................. 41 4.4 不同顶板结构下下煤层顶板破断情况模拟 ........................................................... 44 4.4.1 不稳定层间顶板散体破断模拟 .................................................................... 44 4.4.2 中等稳定层间顶板块体破断模拟 ................................................................ 46 4.4.3 稳定层间顶板结构板式破断模拟 ................................................................ 49 4.5 本章小结 ................................................................................................................... 52 第五章 工程实例 .................................................................................................................... 53 5.1 3318 工作面概况 ....................................................................................................... 53 5.2 3318 工作面矿压规律分析 ....................................................................................... 53 5.2.1 3318 工作面支架阻力数据 ............................................................................ 53 5.2.2 3318 工作面矿压分析 .................................................................................... 55 5.3 本章小结 ................................................................................................................... 56 第六章 结论与展望 ................................................................................................................ 59 6.1 本文主要结论 ........................................................................................................... 59 万方数据 太原理工大学硕士研究生毕业论文 XI 6.2 不足与展望 ............................................................................................................... 60 参考文献 .................................................................................................................................. 61 致 谢 ........................................................................................................................................ 67 攻读学位期间发表的学术论文目录 ...................................................................................... 69 万方数据 太原理工大学硕士研究生毕业论文 XII 万方数据 太原理工大学硕士研究生毕业论文 1 第一章 绪 论 1.1 本文研究背景及意义 在全球煤炭总储量中，我国煤炭占有量有很大的比重。而我国煤炭存在赋存条件复 杂、地质条件差等特点，这也就造成了我国煤炭开采工艺的多样性。随着时间进入二十 一世纪，我国经济固然得到了极快速的发展，但发展的同事其对煤炭的需求量也随之增 大，从而导致了我国煤炭产量到 2000 年来的日益增长。而经过这十余年的煤炭开采， 埋藏浅以及开采条件较好的煤层逐渐开采完毕，下一步将主要针对埋藏深、开采条件较 差的煤层，而这其中近距离薄煤层群占有很大的比例。 许久以来，无论国内相关学者还是国外相关专家对煤层开采时顶板的破断机理研究 都倾向于针对单一煤层工作面开采，而对近距离薄煤层联合开采时顶板的破断机理，特 别是两近距离煤层间上煤层开采完毕后下煤层开采时下煤层的顶板平破断机理研究较 少。相较于单一煤层开采，近距离煤层群联合开采其顶板破断规律、矿压显现规律都有 明显区别。对于近距离煤层群工作面开采而言，当位于上部的煤层被开采后，工作面周 围的围岩应力平衡状态被打破，在一定的区域范围内会形成应力降低区，这势必会对临 近煤层的应力分布状态造成影响，使得下煤层开采时工作面前方应力分布规律与上煤层 开采时有较大变化，另一方面，对于极近距离煤层，由于煤层间距离较近，下煤层开采 时层间结构难以形成稳定的关键层，工作面的来压情况也与单一煤层开采相比有明显差 异。 近距离煤层群由于其赋存条件的复杂性和特殊性，会给巷道掘进以及工作面回采带 来很多不确定因素和安全隐患。而排出这些不确定性和安全隐患最重要的一点就是，探 究近距离煤层群在回采过程中其顶板的破断机理，从而对其矿压显现进行预测，这对于 近距离煤层群联合开采过程中工作面顶板控制以及矿井安全生产具有重要意义。 1.2 国内外研究现状 1.2.1 近距离煤层群定义 就目前来说， 在国内采对于近距离煤层还没有一个比较完整的定义。 前苏联学者斯 列沙烈、包基、库兹涅佐夫夫等以下煤层开挖时的垮落带高度