回采巷道旁静力切顶卸压参数优化研究.pdf

太原理工大学硕士研究生学位论文 万方数据 太原理工大学硕士研究生学位论文 万方数据 太原理工大学硕士研究生学位论文 I 回采巷道旁静力切顶卸压参数优化研究 摘 要 随着无煤柱开采理念的深入人心，沿空留巷技术以其特有的工程特点 和优势在短暂的几十年内得到了迅猛地发展和推广，然而受回采强动压影 响，即使是在强支护作用下留巷断面围岩变形仍然十分严重。为了解决这 个阻碍沿空留巷技术推广和发展的问题，国内外众多学者专家对沿空留巷 的空间结构和力学特征进行了研究，逐渐总结出了以切顶卸压技术为核心 的沿空留巷围岩控制方式，并在现场实践中取得了良好的效果。通过对目 前国内外该领域研究现状的分析可以看出，处理沿空留巷切顶卸压问题的 主要技术措施有爆破预裂法、水力压裂法及高压气体预裂法等。然而由于 火工品爆破释放能量过大，可控性较差，易诱发井下重大安全事故，所以 在一些高瓦斯矿井中限制了爆破预裂卸压法的使用。而水力压裂卸压法虽 然可以避免采用爆破预裂卸压法存在的安全隐患问题，但是其设备要求较 高、工作区域排水困难，且难以达到施工要求致裂压力，碍于此，沿空留 巷水力压裂卸压技术至今仍未在煤矿中大范围地推广和应用。 在基于现有技术存在的缺陷和对亟需解决问题自身特点的考虑下，本 文根据静态破碎剂的工程应用特点，拟考虑将静态破碎技术引入回采巷道 切顶卸压工艺中，并从理论分析、实验室试验和数值模拟三个方面对回采 巷道旁静力切顶卸压技术进行综合研究和分析，取得了一定的研究成果。 通过对新元公司 3108 工作面辅助进风巷（沿空留巷）进行现场调研和 考察，并查阅相关文献，收集到了工作面地质特征、巷道布置情况、煤层 万方数据 太原理工大学硕士研究生学位论文 II 围岩结构以及煤岩的物理力学参数等资料，为沿空留巷静力切顶卸压的研 究和分析做准备；通过实验室设计改良试验对静态破碎剂的膨胀发生机制、 外界因素对膨胀性能的影响特点及反应的阶段过程进行分析，得出了在不 同水灰比、不同孔径及不同水温下的水化反应过程及膨胀压力大小，为后 续试验确定静态破碎参数提供参考和依据；通过对岩石的断裂破坏机理进 行分析，得出了岩石断裂裂纹的扩展机制及其与钻孔内膨胀压力大小、钻 孔半径及钻孔间距的关系，为后续确定钻孔合理孔间距提供理论依据；通 过前述章节公式计算得出了理论孔间距大小，并应用数值模拟确定最佳孔 间距参数，然后通过方案对比确定了最佳的施工方案和参数，为后续试验 提供参数依据和方案选择；通过数值模拟分析了静力切顶卸压前后的围岩 变形特征及应力变化情况，得出了通过静力切顶卸压可以改善沿空留巷围 岩应力条件，减小围岩变形的目的，从而可以说明采用静力破碎切顶卸压 技术对回采巷道围岩控制是有效的。 本文通过实验室试验、理论分析和数值模拟相结合的方法对回采巷道 旁静力切顶卸压技术的相关参数进行了研究和优化，从一定程度上说明了 采用静力破碎切顶卸压的效果和特点，这不仅扩宽了对静态破碎技术应用 方向和领域的思考，也可在一定程度上起到对沿空留巷切顶卸压技术的推 动和革新。本文对类似条件下的回采巷道切顶卸压研究具有一定的借鉴意 义，同时本文针对静态破碎剂膨胀性能试验减小误差的方法提供了参考和 借鉴。 关键词静态破碎，沿空留巷，切顶卸压，围岩变形 万方数据 太原理工大学硕士研究生学位论文 III RESEARCH ON OPTIMIZATION OF STATIC ROOF CUTTING AND STRESS RELEASING PARAMETERS AT THE SIDE OF MINING ROADWAY ABSTRACT Along with the deep popularity of the concept of non coal pillar mining, the technology of gob-side entry retaining has been developed and popularized rapidly in a short period of several decades because of its unique engineering characteristics and advantages. However, the deation of the surrounding rock of the retaining entry under the strong support is still so seriously affected by the strong dynamical mining pressure. In order to solve the problem that stunts the promotion and development of the technology, many scholars at home and abroad have studied the spatial structure and mechanical characteristics of the gob-side entry retaining, and gradually summed up the control means of the surrounding rock along the gob with the core of the roof cutting and stress releasing technology. It has achieved many fruits in the field practice. Through the analysis of the current research status in the field at home and abroad, it can be seen that the main technical measures to deal with the cutting and releasing of the top of the gob-side entry retaining are blasting precracking, hydraulic fracturing and high-pressure gas precracking. However, because the detonation 万方数据 太原理工大学硕士研究生学位论文 IV energy releasing of explosive materials is too large and its controllability is hard, it is easy to induce major safety accidents in the mine, so the use of blasting presplitting and stress releasing is limited in some high gassy mine. Although the hydraulic fracturing stress releasing can avoid the problems of hidden danger in the of blasting presplitting and stress relief, the equipment has higher equipment and be easy to cause difficult drainage in the working area, and it is difficult to achieve the fracturing pressure of the cracking requirements. Based on the defects of the existing technology and the characteristics of the urgent demand to solve the problem, according to the engineering application characteristics of the static crushing agent, the technology is considered to be introduced into the roof cutting and stress releasing process of the mining roadway, and the static statics at the side of the mining roadway are analyzed from three aspects of theoretical analysis, laboratory test and numerical simulation. Comprehensive research and analysis of the roof cutting and stress releasing technology has yielded some research results. Through the investigation on the auxiliary air entry the gob-side entry retaining in the 3108 working face of Xinyuan Mine, and referring to the relevant documents, the data of the geological features of the working face, the layouts of the roadway, the surrounding structure of the coal seam and the physical- mechanical parameters of the coal and rocks are collected, and the research and analysis of the static cutting and stress releasing of the gob is made. 万方数据 太原理工大学硕士研究生学位论文 V Through the analysis of the expansion mechanism of the static crushing agent, the influence characteristics of external factors on the expansion perance and the stage process of the reaction, the hydration reaction process and the size of the swelling stress at different water cement ratio, different inner aperture of steel tube and different water temperature are obtained by the laboratory improvement test. The breakage mechanism of rock is analyzed, and the relationship between the crack propagation mechanism and the ula of the expansion pressure in the borehole, the radius of the borehole and the distance between the drilling holes is obtained. The theoretical basis is provided for the subsequent determination of the rational hole spacing of the drill holes. The optimum hole spacing parameters are determined by numerical simulation, and the best construction scheme and parameters are determined through the comparison of the scheme. The parameter basis and the choice of the scheme are provided for the follow test, in addition,the deation characteristics and variation of stresses of the surrounding rock before and after the static roof cutting and stress releasing are analyzed by numerical simulation. The static roof cutting and stress relief can improve the stress conditions and reduce the deation of the surrounding rock, thus it can be explained that the static crushing and stress relief technique is effective for the control of the surrounding rock. Through the of laboratory test, theoretical analysis and numerical simulation, this paper studies and optimizes the relevant parameters of the static 万方数据 太原理工大学硕士研究生学位论文 VI roof cutting and stress ureleasing technology at the side of the mining roadway. From a certain extent, the effect and characteristics of the static crushing and stress releasing are explained, which not only widens the application direction and field of static crushing technology. It can also play a certain role in promoting and innovating the technology of roof cutting and stress relief along the gob of entry remaining. This paper has a certain reference significance for the study of cutting andrelief under similar conditions. At the same time, it provides reference and reference for the of reducing the error of the expansion perance test of static crushing agent. KEY WORDS static crushing, gob side entry retaining, cutting-roof and unloading-pressure, surrounding rock deation 万方数据 太原理工大学硕士研究生学位论文 VII 目录 第一章绪论.............................................................................................................................1 1.1 选题背景与研究意义...................................................................................................1 1.2 研究现状及存在问题...................................................................................................2 1.2.1 静态破碎技术的研究现状.................................................................................2 1.2.2 沿空留巷切顶卸压技术研究现状.....................................................................8 1.2.3 存在的主要问题...............................................................................................11 1.3 主要研究内容及方法.................................................................................................12 1.3.1 主要研究内容...................................................................................................12 1.3.2 研究方法...........................................................................................................13 1.4 研究技术路线图.........................................................................................................13 第二章静态破碎剂膨胀性能试验.......................................................................................15 2.1 静态破碎剂膨胀机制.................................................................................................15 2.2 试验设计方案.............................................................................................................16 2.2.1 试验原理...........................................................................................................16 2.2.2 试验装置...........................................................................................................18 2.2.3 试验步骤...........................................................................................................21 2.3 不同水灰比对静态破碎剂膨胀性能的影响.............................................................22 2.4 不同水温对静态破碎剂膨胀性能的影响.................................................................25 2.5 不同孔径对静态破碎剂膨胀性能的影响.................................................................26 2.6 水化反应的时间过程分析.........................................................................................28 2.7 本章小结.....................................................................................................................29 第三章岩石断裂破坏机理分析...........................................................................................31 3.1 岩石断裂破坏发生机制.............................................................................................31 3.1.1 断裂力学发展历程...........................................................................................31 3.1.2 断裂裂纹的扩展准则.......................................................................................32 3.2 单孔及多孔加压下岩石破碎理论.............................................................................36 3.2.1 单孔加压破碎研究...........................................................................................36 万方数据 太原理工大学硕士研究生学位论文 VIII 3.2.2 多孔加压破碎研究...........................................................................................38 3.3 单孔及多孔加压数值模拟分析.................................................................................40 3.3.1 模型创建及网格划分.......................................................................................40 3.3.2 单孔加压变形破坏规律...................................................................................40 3.3.3 多孔加压变形破坏规律...................................................................................41 3.4 裂隙演化规律.............................................................................................................43 3.5 本章小结.....................................................................................................................47 第四章静力破碎切顶卸压参数优化及方案选择...............................................................49 4.1 工程背景简介.............................................................................................................49 4.2 切顶钻孔合理孔间距确定.........................................................................................50 4.2.1 钻孔围岩裂隙扩展分析...................................................................................51 4.2.2 钻孔孔间距计算...............................................................................................52 4.2.3 数值模拟确定孔间距.......................................................................................53 4.3 其他关键参数确定.....................................................................................................55 4.4 切顶方案选择.............................................................................................................56 4.5 本章小结.....................................................................................................................60 第五章静力切顶卸压技术数值模拟...................................................................................63 5.1 模型创建及网格划分.................................................................................................63 5.2 开挖过程设置.............................................................................................................64 5.3 数值模拟结果分析.....................................................................................................65 5.3.1 未开挖状态.......................................................................................................65 5.3.2 区域①开挖模拟...............................................................................................66 5.3.3 区域②开挖模拟...............................................................................................67 5.4 本章小结.....................................................................................................................69 第六章结论与展望...............................................................................................................71 6.1 结论.............................................................................................................................71 6.2 不足与展望.................................................................................................................73 参考文献...................................................................................................................................75 致谢.......................................................................................................................................81 万方数据 太原理工大学硕士研究生学位论文 IX 攻读硕士学位期间发表的学术论文.......................................................................................83 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 选题背景与研究意义 自上世纪六、七十年代英、德等国[1]率先将沿空留巷无煤柱开采技术引入煤炭资源 回采方法中以来，因其具有如下的技术优势①提高煤炭资源回采率，降低采空区留煤 量；②提高巷道服务年限及有效利用率，降低巷道掘进量；③构成回采空间 Y 型通风系 统，降低上隅角瓦斯集聚浓度；④削弱应力集中区及利于瓦斯抽采[2]，使其在此后的三、 四十年内得到了迅猛地发展。然而，随着沿空留巷技术的推广应用，也逐渐暴露出一些 影响煤矿安全和技术推广的桎梏，主要包括①留巷在动压作用下变形很大，且巷道维 护困难，维修成本较高；②难以保证有效的通风断面和瓦斯抽采空间[3]。而且，随着浅 层资源的消耗殆尽，煤炭开采逐渐向地层深处延展，势必会因高地压的作用而产生更大 的巷道变形破坏。从全局考虑，这些关键问题的存在，不仅成为制约沿空留巷发展的技 术难题，也是影响煤矿高效集约可持续发展的关键失衡点。因此，采取何种技术措施解 决或弱化这些技术诱发的问题，成为左右沿空留巷无煤柱开采技术发展的关键。 目前，处理沿空留巷变形过大问题的普遍认识，一是增大巷道内支护的结构强度， 但这种方法效果有限[4,5]； 二是对留巷采空区内悬臂顶板结构进行卸压处理， 以转移此间 应力，削弱其对巷道支护结构的作用，达到减少留巷变形的目的，且这种处理方法更为 有效。而现今处理悬顶卸压问题的主要预裂措施包括爆破预裂法、水力压裂法及高压气 体预裂法等，其中尤以前两种更为普遍。 爆破预裂卸压法[6-8]是目前我国发展和应用最为广泛的一种方法， 以定向爆破切顶卸 压自动成巷技术为例，其施工原理是沿工作面前方预留巷道内侧布置深孔预裂爆破炮 孔，对工作面顶板进行超前预裂爆破，使顶板沿预定方向产生切缝，即为切顶线；随着 工作面的不断推进，采空区顶板周期性来压，巷道内侧顶板沿切缝垮落，进而实现切顶 卸压预裂爆破一次成巷，大大减轻采空区顶板来压时对沿空留巷的影响。爆破预裂卸压 法具有设备要求低、施工效果好等技术优势。但煤矿在涉及火工品应用时总是显得谨小 慎微，关键还是因为炸药容易诱发重大安全事故，且因其能量过大，可控性较差。所以， 这也就限制了爆破预裂卸压法在煤矿（特别是一些高瓦斯矿井）中的应用。 水力压裂卸压法[9,10]是由波兰于上世纪 90 年代采用的一种用于处理煤矿坚硬顶板 万方数据 太原理工大学硕士研究生学位论文 2 和冲击地压的方法，而后经国内外众多学者专家的试验研究，并由煤炭科学研究总院研 发了一整套的切槽工艺和施工机具，最终得以推广应用于沿空留巷卸压工艺中。其关键 卸压原理是沿预先布设的钻孔注入高水压以实现预定裂隙的扩展和贯通， 在沿空留巷采 空区悬臂顶板结构垂直层理方向上产生一定角度的贯穿平面，同时借助水的弱化作用， 使该悬臂顶板结构发生冒落，从而转移作用于巷道支护物上的高应力，起到对沿空留巷 支护结构卸压的作用，进而改善沿空留巷的应力状态。此种方法可以避免采用爆破预裂 卸压法存在的安全隐患问题， 并且借助高水压和水弱化作用可以增强卸压的效果。 但是， 水力压裂技术也存在一些根本性的缺点[11]①高压水的加压设备要求高，施工现场难以 满足致裂所需要求；②排水困难，易恶化工作面环境；③采空侧顶板临近采空区，内生 裂隙发育，漏水严重，可能难以达到有效的致裂水压。碍于此，沿空留巷水力压裂卸压 技术至今仍未在煤矿中大范围地推广和应用。 在基于上述技术存在的问题和亟需解决的关键难题的考虑下， 本文拟将静态破碎技 术引入沿空留巷卸压方法中，借助于静态破碎剂可以在“无振动、无飞石，无噪音、无 污染”的条件下完成岩石的破碎工作，分析其在沿空留巷预裂卸压中的应用效果，这对 煤矿提出的“安全高产高效可持续生产”具有十分重要的研究意义。因此，