缓倾斜薄煤层采动巷道矿压显现规律及围岩控制机理研究.pdf

缓倾斜薄煤层采动巷道矿压显现规律及围岩 控制机理研究 重庆大学硕士学位论文 （专业学位） 学生姓名徐 波 指导教师曹树刚 教 授 兼职导师刘朝富 高 工 学位类别工程硕士（矿业工程领域） 重庆大学资源及环境科学学院 二 O 一七年四月 万方数据 万方数据 Study on Pressure Behaviors Law and Surrounding Rock Control Mechanism of Mining Roadway in Gently-Inclined and Thin Coal Seam A Thesis ted to Chongqing University In Partial Fulfillment of the Requirement for the Professional Degree By Xu Bo Supervised by Prof. Cao Shugang Pluralistic Supervised by Sn.Engr. Liu Chaofu Specialty M.E Mineral Engineering Field College of Resources and Enviromental Science of Chongqing University, Chongqing, China. April, 2017 万方数据 万方数据 中文摘要 I 摘 要 一般而言，煤矿井下受到采动影响的回采巷道（简称“采动巷道”）围岩破 坏严重，矿压显现剧烈，围岩控制难度大。针对以上存在的问题，本论文采用数 值计算和现场监测方法，对采动巷道的变形、破坏规律以及围岩控制技术开展研 究。主要研究工作、内容及结论为 ①对西南地区某煤矿开展了现场调研，并通过钻取煤岩试样进行力学测试， 获得了目标煤层采场煤岩层的物理力学参数。 ②构建缓倾斜薄煤层三维采场力学计算模型。对分步开挖条件下，采场围岩 内的应力分布及演化规律进行分析，获得了采场侧向及工作面前方支承压力的变 化规律；对采动过程中采场底板应力分布进行分析，结果显示，缓倾斜薄煤层中 采动造成的底板应力重分布影响可达到约 6.7 倍采高区域，底板破坏呈现“勺形” 的非对称破坏形态。 ③基于对巷道围岩的弹塑性理论分析，得到巷道围岩变形主要取决于巷道所 处岩层的原岩应力、岩石内聚力和内摩擦角、巷道支护阻力以及巷道开挖半径。 其中，围岩塑性区半径与巷道半径、原岩应力成正比，与内聚力、内摩擦角以及 巷道支护阻力成反比关系。 ④通过对双巷开掘数值分析，获知双巷空间的相对位置对巷道围岩变形和破 坏具有显著影响。随着水平和垂直错距的增加，巷道间的相互影响迅速减小，顶 底板和两帮相对移近量也明显减小；相邻巷道的开掘对已掘进巷道产生明显动载 影响；随着开掘距离的临近，相邻巷道围岩塑性区逐渐联通，相邻巷道间岩柱在 双巷帮部岩体的垂直载荷作用下多呈现剪切破坏形式；巷道围岩内支承压力的叠 加是造成围岩变形量增加的主要原因，而岩柱的完整性是影响叠加载荷传递效率 的重要原因。 ⑤通过不同应力集中系数下巷内支护设计数值模拟，得出高应力集中系数对 巷道围岩变形破坏影响显著；在不同的锚杆密度下，异形巷道的高应力区主要出 现在顶板高帮顶角处和两帮底脚处；围岩的整体性直接影响顶底板及两帮的破坏 深度，但通过施加槽钢可有效减少围岩破坏范围，降低巷道边角的应力集中程度。 ⑥从实际生产出发，结合现场调查和矿压监测，选用现场实例对比分析了回 采巷道在受到煤层开挖影响前后的变形破坏规律；选用桁架锚索加强支护后，采 动巷道围岩控制效果较好。 关键词关键词采动巷道，支承压力集中系数，数值模拟，巷道围岩控制，矿压监测 万方数据 重庆大学硕士学位论文 II 万方数据 英文摘要 III ABSTRACT In general, the mining roadway impacted by the mining under coal mine, referred to as “mining roadway“. For mining roadway, there are some serious problem, such as serious damage to the surrounding rock, strata appears violent, difficult to control the surrounding rock, etc. In view of the above problems, this paper uses numerical calculation and on-site monitoring to study the deation, failure law and surrounding rock control technology of mining roadway. The main research contents and conclusions are as follows ①Get the overview of coal seam geological occurrence characteristics and working face through field research; The mechanical properties of the coal seam and the top and bottom of the obtained through laboratory tests to check the numerical test parameters by trial approximation . ②The calculation model of the 3D stope is constructed, and the regularity of the mining pressure in the coal mining process is analyzed by numerical simulation. The stress distribution and evolution law of the surrounding rock are analyzed under the step excavation condition, and the change rule of the bearing pressure in the side of the stope and the working face is obtained. The stress distribution of the bottom of the stope during the mining process is analyzed The results show that the stress distribution of the floor caused by the mining can reach about 6.7 times the height of the mining area, the bottom plate failure showed a “spoon-shaped“ asymmetric failure. ③Based on the elastic-plastic analysis of surrounding rock of roadway, it is concluded that the deation of roadway surrounding rock is mainly determined by the original stress, the cohesion and internal friction angle of rock, the resistance of roadway support and the radius of tunnel excavation. Among them, the radius of the plastic zone of the surrounding rock is directly proportional to the radius of the roadway and the original rock stress, and is inversely proportional to the cohesion and internal friction angle and the roadway support resistance. ④Based on the numerical analysis of double lane excavation, it is concluded that the spatial location of double lane has a significant influence on the deation and failure of surrounding rock. With the increase of the horizontal and vertical errors, the interaction between the roadway decreases rapidly. The adjacent roadway has obvious influence on the dynamic load has been heading, with the increase of spatial distance, 万方数据 重庆大学硕士学位论文 IV the top floor and two sides of relative volume significantly decreased; with the excavation distance approaching, adjacent roadway surrounding rock plastic zone is China Unicom; adjacent road vertical load of rock pillar in double lane side under the rock present shear failure . The main reason for the increase of the deation of surrounding rock is the superposition of the abutment pressure in the surrounding rock. ⑤Through the numerical simulation of the tunnel support design under different stress concentration factors, it is concluded that the high stress concentration factor has significant influence on the deation and failure of the surrounding rock. In the anchor density under different shaped roadway in high stress area mainly appeared in the roof at the top and two for help at the foot. Two for high strength support can effectively limit the large deation of surrounding rock, but also easy to a high stress concentration, not only in the two to help the ation of high strength of the stress concentration caused by the bottom edge at the foot of the larger shear stress concentration, resulting in destruction of heave. ⑥Starting from the actual production, combined with field survey and mine pressure monitoring, comparative analysis of the roadway in coal seam excavation effect before and after the selection of truss cable reinforced timbering, mining roadway surrounding rock control effect is good. Keywords Mining roadway, Support pressure concentration coefficient, Numerical simulation, Control of surrounding rock of roadway, Mine-pressure monitoring. 万方数据 目 录 V 目 录 中文摘要中文摘要 .......................................................................................................................................... I 英文摘要英文摘要 ....................................................................................................................................... III 1 绪绪 论论 ......................................................................................................................................... 1 1.1 研究背景及意义研究背景及意义 ....................................................................................................................... 1 1.2 国内外研究现状国内外研究现状 ....................................................................................................................... 2 1.2.1 采场矿压显现规律研究现状 ........................................................................................... 2 1.2.2 采动巷道围岩变形破坏研究现状 ................................................................................... 4 1.2.3 采动巷道围岩稳定性控制研究现状 ............................................................................... 5 1.3 研究内容与技术路线研究内容与技术路线 ............................................................................................................... 6 2 工程背景及岩层力学性能实验研究工程背景及岩层力学性能实验研究 ......................................................................... 9 2.1 概述概述 ........................................................................................................................................... 9 2.2 地质概况地质概况 ................................................................................................................................... 9 2.3 煤（岩）力学性质实验研究煤（岩）力学性质实验研究 ................................................................................................. 11 2.3.1 试样制备 ......................................................................................................................... 11 2.3.2 实验设备 ......................................................................................................................... 11 2.3.3 实验方法 ......................................................................................................................... 12 2.3.4 实验结果分析 ................................................................................................................. 13 2.4 本章小本章小结 ................................................................................................................................. 16 3 采场采动应力分布演化及底板破坏规律分析采场采动应力分布演化及底板破坏规律分析 ................................................. 17 3.1 概述概述 ......................................................................................................................................... 17 3.2 数值模型的建立数值模型的建立 ..................................................................................................................... 18 3.2.1 FLAC3D模拟软件简介 .................................................................................................... 18 3.2.2 数值计算参数 ................................................................................................................. 18 3.2.3 数值计算模型 ................................................................................................................. 19 3.3 采场采场采动应力分布及演化规律采动应力分布及演化规律 ............................................................................................. 20 3.3.1 采场支承压力分布及演化规律 ..................................................................................... 20 3.3.2 采场底板垂直应力分布及演化规律 ............................................................................. 24 3.4 煤层底板破坏区分析煤层底板破坏区分析 ............................................................................................................. 27 3.4.1 煤层底板破坏形态分析 ................................................................................................. 27 3.4.2 煤层底板破坏区发育规律 ............................................................................................. 28 3.5 本章小结本章小结 ................................................................................................................................. 29 万方数据 重庆大学硕士学位论文 VI 4 采动巷道矿压显现及围岩控制机理分析采动巷道矿压显现及围岩控制机理分析 ............................................................ 31 4.1 概述概述......................................................................................................................................... 31 4.2 开挖巷道围岩变形机理开挖巷道围岩变形机理 ......................................................................................................... 31 4.3 相邻巷道掘进扰动条件下围岩变形破坏规律相邻巷道掘进扰动条件下围岩变形破坏规律 ..................................................................... 35 4.3.1 双巷掘进模型 ................................................................................................................. 35 4.3.2 受邻巷掘进影响巷道围岩变形及破坏规律 ................................................................. 36 4.4 采动巷道围岩控制机理及支护效果分析采动巷道围岩控制机理及支护效果分析 ............................................................................. 41 4.4.1 锚杆支护理论及巷道支护模型 ..................................................................................... 42 4.4.2 不同支护下采动巷道围岩塑性区演化规律 ................................................................. 45 4.4.3 不同支护下采动巷道围岩应力分布规律 ..................................................................... 48 4.4.4 不同支护下采动巷道围岩变形特征 ............................................................................. 50 4.5 本章小结本章小结 ................................................................................................................................. 52 5 采动巷道变形破坏及支护现场实例分析采动巷道变形破坏及支护现场实例分析 ............................................................ 55 5.1 概述概述......................................................................................................................................... 55 5.2 采动巷道变形破坏现场分析采动巷道变形破坏现场分析 ................................................................................................. 55 5.2.1 S8104 回风巷巷内支护 ................................................................................................... 55 5.2.2 S8104 回风巷超前支护 ................................................................................................... 56 5.2.3 S8104 回风巷变形分析 ................................................................................................... 57 5.3 采动巷道巷内支护改进及矿压监测采动巷道巷内支护改进及矿压监测 ..................................................................................... 57 5.3.1 S8104 回风巷支护改进 ................................................................................................... 57 5.3.2 S8104 回风巷矿压监测对比分析 ................................................................................... 58 5.4 本章小结本章小结 ................................................................................................................................. 61 6 结论与展望结论与展望 ............................................................................................................................ 63 6.1 结论结论......................................................................................................................................... 63 6.2 展望展望......................................................................................................................................... 64 致致 谢谢 ...................................................................................................................................... 65 参考文献参考文献 ...................................................................................................................................... 67 附附 录录 ...................................................................................................................................... 71 A．作者在攻读学位期间参与的科研项目．作者在攻读学位期间参与的科研项目 ................................................................................ 71 万方数据 1 绪 论 1 1 绪 论 1.1 研究背景及意义 中国从十九世纪六十年代开始，就把煤炭资源作为主要能源[1]。煤炭在我国一 次性能源生产和消费中一直占有重要的地位，所占比重超过 60的现状亦将长期 存在。据相关研究表明[2]，预计到 2030 年，煤炭在我国能源消费中仍将占 70左 右，全国对煤炭的需求量依然不减。 过去的十年间，中国经济形势较好，煤炭市场火热，各生产矿井的产量及其 采掘机械化的程度都得到了空前提高，高强度的采掘导致大多数埋深浅和开采条 件好的煤层资源几近枯竭。为适应国家经济持续的快速发展，确保能源需求，许 多煤炭企业不断扩大产能，越来越多的矿井开采开始转向地质条件复杂的深部煤 层甚至近距离的薄煤层群。开采煤层的赋存条件变得复杂恶劣，采场矿压显现剧 烈，采动影响范围及强度激增，特别是高地应力环境导致采煤工作面支承压力急 剧增加，采动巷道的围岩控制愈发困难。面对以上问题，在进行支护设计时，往 往采用经验类比法，缺乏科学的指导。采动巷道支护设计不尽合理，导致顶板难 于管理、围岩难以控制等技术问题日益突出。如图 1.1 所示，西南地区某煤矿采动 巷道受煤层开采剧烈影响后，出现了较大的巷道变形失稳及锚杆失效等问题。 （1）顶板锚杆失效 （2）顶板锚网兜渣 （3）煤体破碎挤出 （4）墙体破碎锚网失效 图 1.1 西南地区某煤矿采动巷道破坏情况 Fig.1.1 Southwest region certain coal mine roadway destruction 万方数据 重庆大学硕士学位论文 2 回采巷道与工作面空间的相对位置，以及相邻巷道的开掘情况均会对围岩内 的应力状态产生显著影响，进而在巷道局部区域造成不同的应力集中或卸载。诸 如此类的应力状态改变，最终均将表现为巷道围岩变形量的增加，矿压显现加剧。 因此，在采掘影响下产生的回采巷道支护与维护问题日显突出，成为一些矿区高 产高效与安全生产的主要制约因素，给矿区可持续健康发展带来了极为不利的影 响。因此，针对煤层回采过程中采动应力分布演化规律、采场围岩破坏区形态特 征，以及不同的应力环境条件下，对回采巷道围岩控制机理的分析研究具有重要 意义。本研究针对采动巷道矿压显现规律及大变形机理开展研究，综合现场调研、 物理实验、数值模拟、理论分析和现场监测等研究手段，分析采动巷道的围岩控 制机理。研究结果为更好地理解采动巷道矿压显现规律提供了科学思路，为巷道 围岩控制提供理论依据。 1.2 国内外研究现状 1.2.1 采场矿压显现规律研究现状 ①采动应力分布及演化规律研究 工作面的掘进、回采会使得采场本处于原岩应力平衡的状态发生变化，且随 着工作面的推进，此变化表现为动态演化。因此，对采动应力分布及变化规律开 展研究显得尤为重要。过去几十年，国内外学者对矿山压力及采场应力分布规律 进行了大量的研究和分析，亦取得了丰硕的成果。钱鸣高院士等人[3]将采场围岩内 的垂直应力分为减压区、增压区和稳压区三个