“上柱-下垮”复合残采区中层弃煤开采围岩运移规律及其采序影响.pdf

太原理工大学硕士学位论文 I “上柱-下垮”复合残采区中层弃煤开采 围岩运移规律及其采序影响 摘 要 “上柱-下垮”复合残采区中部整层弃煤赋存广泛，储量可观，为了提 高煤炭资源的回收率，实现复合残采区残煤复采是势在必行的一个课题。 在上下煤层开采的双重采动影响下，复合残采区中部弃煤顶板活动规律、 底板移动变形规律及层间岩层应力分布规律等与单一残采区煤层开采相比 具有较大的差异性，已有的研究成果已不适用于出现的新问题。而当前复 合残采区中部整层弃煤能借鉴的经验较少，国内外尚无系统的理论研究和 成套的技术方案来科学地指导其安全生产。因此，深入、系统地对复合残 采区中部整层弃煤开采过程中采场岩层应力分布、移动变形、结构演化及 破坏特征等方面进行研究是迫切而重要的。 本文针对西山煤电白家庄煤矿“上柱-下垮”复合残采区中部整层弃煤的 开采，综合运用现场调研、相似模拟、数值模拟、理论分析等手段，系统 研究了各煤层开采过程对中部残煤采场岩层“应力分布-移动变形-结构演 化”造成的影响，同时针对此类型复合残采区的两种不同形成方式，分析 了不同开采顺序对中部残煤采场岩层的影响，并得出了对中部残煤及其顶 底板岩层扰动影响最小的开采顺序，对此类工程应用提供了借鉴，确定了 更合理的开采顺序。上述研究对中部整层弃煤的安全高效开采提供了理论 依据，进一步丰富了残煤复采的内涵。主要研究内容及成果如下 （1）当下部煤层开采完毕后，其采空区上覆岩层处于应力降低区，最 终形态表现为“卸压拱”，影响范围主要集中于下位层间岩层，中部残煤采 场岩层在一定程度上产生了卸压效应。长壁垮落采空区上覆不同层位的岩 层垂直应力变化规律不同，与下部煤层垂距越小的岩层其支承压力峰值越 大。下部煤层开采完毕呈最终稳态后，岩层结构向上扩展至上部煤层，无 万方数据 太原理工大学硕士学位论文 II 裂隙岩层区贯穿了整个上位层间岩层，且自中部煤层底板向上均未发生台 阶式的破断，保持了宏观连续性和完整性。由下部煤层垮落开采在其开采 工作面垂直方向损伤破坏范围的理论分析可知，下部煤层的开采并未对中 部煤层造成损伤破坏。 （2）当上部煤层采用刀柱法开采，开采条带数目多于4个时，开采形 成的刀柱煤柱影响范围基本稳定，这表明其对下部岩层的破坏范围不再扩 大；当开采条带数目多于5个时，柱采区域下部岩层“应力恢复”现象消失， 其卸压效应基本稳定。当上部煤层采用刀柱煤柱开采过程中，中部残煤采 场岩层其应力分布在水平方向上应力增高区与应力降低区交替显现，与上 部煤层的垂距越小，其应力集中程度越大，中部煤层中产生了较显著的应 力集中现象。上部煤层采用刀柱法开采后，上部煤层顶底板岩层受采动影 响其移动变形基本呈现“中间高、两边低”的波浪状分布。由上部煤层开采 其采场岩层损伤破坏范围理论分析可知，中部残煤处于上部煤层开采造成 的损伤破坏范围内，在开采过程中须对中部煤层顶板进行实时监控。 （3）中部残煤开采对煤层采场应力分布的影响表现为中部煤层向前 推进不同距离均产生了不同的卸压效应，不同岩层层位的测线其垂直应力 仍以“波浪状”分布。从位移数据中能反映出，中部煤层顶板下沉量达到最 大值的位置位于上部煤层柱式采空区中心轴线位置， 中部煤层开采过程中， 塑性区主要分布于岩性软弱的层间岩层中，其采场顶板发生了显著的塑性 破坏，其破坏范围基本贯穿整个上位层间岩层。 （4）通过分析两种不同开采顺序条件下其上、下煤层开采对中部残煤 应力分布、移动变形、破坏特征等造成的影响，得到结论在此类工程问 题中，“上-下-中”开采顺序对中部残煤及其顶底板岩层的扰动影响更小。 关键词“上柱-下垮”复合残采区，中部残煤，应力分布，移动变形，结 构形式，开采顺序 万方数据 太原理工大学硕士学位论文 III STUDY ON MOVEMENT OF SURROUNDING ROCK AND INFLUENCE OF MINING SEQUENCE IN MINING MIDDLE ABANDONED COAL SEAM WITH “UPPER PILLER-LOWER LONGWALL” RESIDUALAREAS ABSTRACT The whole layer of the abandoned coal seam in “Upper pillar-Lower longwall” composite mining areas reserves occur widely, objectively, in order to improve the recovery rate of coal resources, realize repeated mining in the composite residual mining area is an imperative topic.In the dual mining influence of “upper-lower” coal seam mining, the laws of upper coal floor movement , lower coal floor deation and the stress distribution between the rock strata in “Upper pillar-Lower longwall” composite mining areas and the residual coal mining single mining area compared with the large difference, the existing research results are not applicable to the emergence of new issues.Less experience and the current central composite residual mining area whole layer of abandoned coal can be used for reference at home and abroad, there is no systematic theoretical research and complete technical solutions to the scientific guidance for safe production.Therefore, thorough and systematical studyon thestrataof“stressdistribution-movementanddeation-structure evolution-failure characteristics“ in mining middle abandoned coal seam with “Upper pillar-Lower longwall” composite mining areas research is urgent and important. The middle abandoned coal seam No.7 with “Upper pillar-Lower longwall” composite mining areas in Baijiazhuang coal mine,which belongs to Xishan Coal Electricity Group, is selected as the research object. The research s includefieldinvestigation,theoreticalanalysis,similarsimulationand numerical simulation. The influence of upper pillar-lower longwall mining on 万方数据 太原理工大学硕士学位论文 IV stress distribution, moving deation and structure evolution are explored firstly.At the same time for this type of composite residual are in two different s,analyzes the different effect of mining sequence for strata of middle residual coal,finally got the optimal mining sequence.The research on the middle layer of the abandoned coal safe and efficient mining provides theoretical basis to further enrich.The main research contents and results are as follows 1The goaf overburden is in the lower stress area after the lower coal seam mining , its final is “unloading arch“ effect, mainly concentrated in the lower layer between the middle strata, middle residual coal stope rock to a certain extent the pressure relief effect.The vertical stress variation law of overlying strata in longwall goaf is different, and the smaller the vertical distance of the lower coal seam and strata, the larger the peak value of supporting pressure in these strata.After a final steady state of lower coal seam mining, rock structure extended up to the upper coal seam, non fractured rock zone throughout the entire upper layer between layers, and from the central to the coal seam floor did not occur step broken, keep the macro continuity and integrity.According to the theoretical analysis of the damage range of the lower coal seam longwall mining in the vertical direction of the mining face, it can be seen that the exploitation of the lower coal seam has not caused damage to the middle coal seam. 2When the upper coal seam use longwall pillar mining , mining the band number more than 4, the influence of coal pillar pillar mining range ed basically stable, which shows that the lower rock damage range is no longer expanding; when the strip number is more than 5, pillar mining areas the lower strata “stress recovery“ phenomenon disappeared. The pressure relief effect, basically stable.In the process of mining upper coal seam with pillar mining , the central residual coal rock strata stress distribution in the horizontal direction stress increasing zone and stress decreasing zone appear 万方数据 太原理工大学硕士学位论文 V alternately, and the vertical distance of strata and upper coal seam is smaller,which has greater the degree of stress concentration, the stress concentration phenomenon is significant in the middle coal seam.After mining upper coal seam with pillar mining , the upper coal seam roof and floor rock layer is affected by the deation showed distribution of high middle and low on both sides looks like wave.According to the theoretical analysis of the damage range of the coal seam in the upper coal seam mining, it can be seen that the residual coal in the middle is in the range of damage,which caused by the upper coal seam mining,the middle coal seam roof needs real time monitoring. 3Mining the middle of the abandoned coal seam caused influence about the stress distribution of coal seam, as follows mining the middle coal seam different distance have different pressure relief effect, different rock layers and the vertical stress is still in “wave“ distribution.It can be reflected from the displacement data, central coal seam roof subsidence reaches the maximum value of the position is located in the upper coal seam goaf center column axis position.The process of mining middle coal seam, the plastic zone is mainly distributed in the upper layer and lower layer of rock between the rock lithology soft strata, in the stope roof the plastic deation occurs significantly, its basic damage range throughout the upper layer of rock. 4Through the analysis of mining upper and lower coal seam caused influence to the middle coal seam about stress distribution,movement and deation, damage range..movement and deation-structure evolution under the condition of two different mining sequence.the conclusion can be drawn in such engineering problems, optimal mining sequence is “firstly mining upper coal seam-secondly mining lower coal seam-finally mining middle coal seam”. 万方数据 太原理工大学硕士学位论文 VI KEYWORDS “Upper pillar-Lower longwall” composite mining areas,middle residualcoalseam,stressdistribution,movingdeation,structure ,mining sequence 万方数据 太原理工大学硕士学位论文 I 目录目录 摘 要...........................................................................................................................................I ABSTRACT.............................................................................................................................III 目录.............................................................................................................................................I 第一章 绪论..............................................................................................................................1 1.1 研究背景......................................................................................................................1 1.2 研究意义......................................................................................................................3 1.3 研究现状......................................................................................................................4 1.3.1 残煤复采研究现状............................................................................................4 1.3.2 采场顶板岩层移动变形研究现状....................................................................6 1.3.3 采场底板岩层移动变形研究现状....................................................................7 1.4 研究内容......................................................................................................................8 1.5 研究方法......................................................................................................................9 第二章 工程概况与试验设计................................................................................................11 2.1 矿井概况.....................................................................................................................11 2.1.1 煤层赋存..........................................................................................................11 2.1.3 开采现状..........................................................................................................12 2.2 相似材料模拟试验设计............................................................................................12 2.2.1 试验原理与内容..............................................................................................12 2.2.2 试验方案设计..................................................................................................13 2.2.3 参数选取..........................................................................................................14 2.2.4 测试方案设计..................................................................................................16 2.3 数值模拟试验设计.....................................................................................................19 2.3.1 概述..................................................................................................................19 2.3.2 模型建立..........................................................................................................19 2.3.3 开采方案..........................................................................................................20 2.4 本章小结.....................................................................................................................20 第三章 复合残采区“下垮”开采对中部残煤采场的影响.................................................... 23 3.1 概述.............................................................................................................................23 3.2 垮落开采对中部残煤采场岩层应力分布的影响....................................................23 万方数据 太原理工大学硕士学位论文 II 3.2.1 垮落开采对应力分布影响的数值模拟分析..................................................23 3.2.2 垮落开采对应力分布影响的相似模拟分析..................................................25 3.3 垮落开采对中部残煤采场岩层移动变形规律的影响............................................26 3.3.1 垮落开采对移动变形影响的数值模拟分析..................................................26 3.3.2 垮落开采对移动变形影响的相似模拟分析..................................................29 3.4 垮落开采对中部残煤采场结构形式演化规律的影响............................................30 3.4.1 垮落开采对结构形式演化规律影响的相似模拟分析..................................31 3.4.2 垮落开采对采场岩层破坏特征的数值模拟分析..........................................32 3.5 下部煤层开采采场岩层损伤范围理论分析............................................................34 3.6 本章小结....................................................................................................................36 第四章 复合残采区“上柱”开采对中部残煤采场的影响.................................................... 39 4.1“上柱”开采支承压力在层间岩层中的传播.............................................................. 39 4.1.1 试验方案的制定..............................................................................................39 4.1.2 试验结果分析..................................................................................................40 4.2 “上柱”开采对中部残煤采场岩层应力分布的影响................................................. 42 4.2.1 对应力分布影响的数值模拟分析..................................................................42 4.2.2 对应力分布影响的相似模拟分析..................................................................44 4.3 “上柱”开采对中部残煤采场岩层移动变形的影响................................................. 45 4.3.1 对移动变形影响的数值模拟分析..................................................................45 4.3.2 对移动变形影响的相似模拟分析..................................................................48 4.4 “上柱”开采对中部残煤采场岩层结构形式演化规律的影响................................. 49 4.4.1 对结构形式演化规律影响的相似模拟分析..................................................49 4.4.2 对破坏特征影响的数值模拟分析..................................................................50 4.5 上部煤层开采采场岩层损伤范围理论分析............................................................52 4.6 本章小结....................................................................................................................54 第五章 中部残煤开采对采场岩层的影响分析....................................................................57 5.1 中部残煤开采采场岩层应力分布演化规律分析....................................................57 5.1.1 采场岩层应力演化规律的数值模拟分析......................................................57 5.1.2 采场岩层应力演化规律的相似模拟分析......................................................59 5.2 中部残煤开采采场岩层移动变形规律分析............................................................60 万方数据 太原理工大学硕士学位论文 III 5.2.1 采场岩层移动变形规律的数值模拟分析......................................................60 5.2.2 采场岩层移动变形规律的相似模拟分析......................................................63 5.3 中部残煤开采采场岩层结构形式演化规律分析....................................................64 5.3.1 采场岩层结构形式演化规律的相似模拟分析..............................................64 5.3.2 采场岩层破坏特征的数值模拟分析..............................................................65 5.4 本章小结....................................................................................................................67 第六章 开采顺序对复合残采区中部残煤采场的影响........................................................69 6.1 概述............................................................................................................................69 6.2 “上-下-中”开采顺序条件下各煤层开采对中部残煤的影响分析...........................69 6.2.1 上部煤层刀柱开采对中部残煤的影响..........................................................69 6.2.2 下部煤层垮落开采对中部残煤的影响..........................................................73 6.3 开采顺序对复合残采区中部残煤采场的影响........................................................77 6.3.1 不同开采顺序采场岩层应力分布演化规律分析..........................................78 6.3.2 不同开采顺序采场岩层移动变形演化规律分析..........................................79 6.3.3 不同开采顺序采场岩层结构形式演化规律分析..........................................79 6.4 本章小结...........................................................