大倾角煤层走向长壁综放工作面顶板结构特征研究.pdf

论文题目大倾角煤层走向长壁综放工作面顶板结构特征研究 专业采矿工程 硕 士 生晏锐签名 指导教师伍永平签名 摘要 大倾角煤层开采，在工作面顶板岩层中形成结构，工作面矿压显现是顶板结构失稳 的外在表现。大倾角煤层走向长壁综放工作面顶板结构是一个复杂的空间结构，其结构 特征及稳定性分析一直以来都是大倾角煤层走向长壁综放开采的一大难题。因此，研究 大倾角煤层走向长壁综放工作面顶板结构特征，对完善大倾角煤层开采理论和岩层控制 理论具有重要意义，对大倾角煤层走向长壁综放工作面支护结构设计、矿山压力控制、 安全高效开采等工程实践具有指导作用。 本文采用现场调研、数值模拟、物理相似模拟、理论分析和现场实测相结合的研究 方法，对大倾角煤层走向长壁综放工作面顶板断裂特征、倾向砌体结构特征和覆岩承载 拱结构特征进行了研究。研究表明 （1）大倾角煤层走向长壁综放工作面基本顶初次断裂裂隙形态为“XO”型。虽 然最终断裂形态与缓倾斜煤层的“OX”型断裂形态相似，但由于岩层重力沿层面方向 的分力较大，导致其断裂裂隙的产生及发展过程与缓倾斜煤层不同。工作面基本顶初次 断裂后，沿采空区端基本顶的移动空间和受力状态与初次断裂之前不同，导致大倾角煤 层走向长壁综放工作面基本顶周期断裂裂隙形态为“CX”型。 （2） 大倾角煤层走向长壁综放工作面基本顶断裂成岩块后， 沿工作面倾向易于形成 砌体结构。倾向砌体结构承担了一部分基本顶岩层自重，减小了基本顶岩层对支架传递 力的作用；倾向砌体结构的稳定性将直接影响工作面支架的受力状态。倾向砌体结构可 能发生的失稳形式为滑落失稳和挤压变形失稳； 最容易发生失稳的部位为工作面中上部。 现场应采取加强对工作面中上部支架工作状态的监测以及提高支架支护强度，防止工作 面中上部倾向砌体结构失稳。 （3） 大倾角煤层走向长壁综放工作面基本顶上覆岩层中形成承载拱结构。 承载拱结 构位于砌体结构的上部岩层中， 沿工作面走向为对称平拱， 沿工作面倾向为非对称斜拱。 走向承载拱结构容易发生沿拱脚处的剪切破坏， 倾向承载拱结构容易发生轴向压缩破坏。 走向承载拱结构对整个工作面基本顶上覆岩层起控制作用，倾向承载拱结构失稳是由于 走向承载拱结构的失稳而导致的。承载拱结构具有承担上覆岩层自重的能力，并对其下 方工作面顶板及支架起保护作用，阻止了基本顶上覆岩层对其下方砌体结构和支架传递 力的作用；当承载拱结构发生失稳时，将会给其下方砌体结构传递力的作用，并导致倾 向砌体结构失稳，产生工作面来压现象。 论文研究结果与枣泉煤矿 120210 综放工作面现场实测相吻合， 为该矿后续工作面及 回采巷道布置方式、回采工艺选择、设备配置提供依据，对该矿安全高效生产有着重要 的指导意义。 关 键 词大倾角煤层；弹性薄板；三铰拱；倾向砌体；承载拱 研究类型应用研究 SubjectStructures of roof Strata at Longwall Mining Face with Fully-mechanized Caving in Steeply Dipping Seam Specialty Mining Engineering NameYan Rui（（Signature）） InstructorWuYongping（（Signature）） ABSTRACT Structures of roof strata is ed in the mining face of steeply dipping seam,the strata pressure behavior of mining face is due to destabilization of these structures.As structures of roof strata at longwall mining face with fully-mechanized caving in steeply dipping seam are complex spatial structures.Its structural characteristics and stability analysis have always been a major problem in longwall mining face with fully-mechanized caving in steeply dipping seam.Therefore, the study on these structures of roof strata can improve the theory of coal mining and ground control in steeply dipping seam.Also, it has an important significance for guiding supporting structure design, ground control, safe and efficient coal mining and other engineering practices in steeply dipping seam. By the use of on-site investigation, numerical simulation, physical simulation, theoretical analysis and field measurement, to study fracture characteristics of main roof, propensity masonry structure and bearing arch structure of overburden strata at longwall mining face with fully-mechanized caving in steeply dipping seam.The results as follows 1 The initial fracture cracks in main roof is “X-O” type at longwall mining face with fully-mechanized caving in steeply dipping seam.Although the final fracture morphology is similar to gently inclined seam main roof which is “O-X” type.But the component force of gravity which is parallel to the strata direction is large,which is lead to the fracture cracks emerging and development process is different to gently inclined seam.After the initial fracture in main roof, restriction effect and mobile space of main roof at the gob area side is different to initial fracture.Resulting in the cycle fracture cracks in main roof is “C-X”type at longwall mining face with fully-mechanized caving in steeply dipping seam. 2 After the main roof broken into rocks, which are easy to propensity masonry structure.Which bears a part of main roof rock weight, reducing the role of the basic roof rock to transmit force of the stent.The stability of propensity masonry structure will directly affect the stress state of supports at longwall mining face with fully-mechanized caving in steeply dipping seam.propensity masonry structure may occur extrusion deation instability and sliding instability. The upper part of propensity masonry structure in the site is most prone instability, so the hydraulic supports in the upper part of face should be strengthened and monitored. 3 Bearing arch structure is ed in overburden strata at longwall mining face with fully-mechanized caving in steeply dipping seam.Bearing arch structure in the upper strata of masonry structure, Along strike of mining face is symmetrical flat arch and along dip of mining face is asymmetric inclined arch.Instability also different between the two models, the fist one usually occurs shear failure,but the other one typically occurs the axial compressive failure.Generally the symmetrical flat arch plays a dominant role,the instability of asymmetric inclined arch result from the instability of symmetrical flat arch.Bearing arch structure with the ability to bear the weight of overburden strata and to protect strata and hydraulic supports in mining face under it, it also can prevente the strata over main roof to transmit force to masonry structure and hydraulic supports.When bearing arch structure instability, it’s power will be transferring to masonry structure under it,and leading to masonry structure instability.As a result of strata pressure behavior showing. Thesis research results consistent with site measurement of NO.120210 longwall mining face with fully-mechanized caving in Zaoquan coal mine.It can provide the basis for roadway layout,mining technology, process and equipment configuration in the follow-up mining faces. It has a great significance for safety and efficient production in Zaoquan coal mine. Key words Steeply dipping seam； Elastic thin plate； Three-hinged arch； Propensity masonry； Bearing arch ThesisApplication research 目 录 I 目录 1 绪论..........................................................................................................................................1 1.1 选题背景及研究意义...................................................................................................1 1.2 工程背景.......................................................................................................................2 1.3 国内外研究现状...........................................................................................................2 1.3.1 国外大倾角煤层开采研究现状........................................................................2 1.3.2 国内大倾角煤层开采研究现状........................................................................3 1.3.3 国内外研究现状综述........................................................................................7 1.4 研究内容、方法和技术路线.......................................................................................7 1.4.1 研究内容............................................................................................................7 1.4.2 研究方法............................................................................................................7 1.4.3 技术路线............................................................................................................8 2 工作面顶板结构特征数值模拟............................................................................................10 2.1 数值模拟研究的内容及方法.....................................................................................10 2.1.1 研究内容..........................................................................................................10 2.1.2 计算方法..........................................................................................................10 2.1.3 计算软件..........................................................................................................10 2.1.4 计算参数..........................................................................................................11 2.2 数值模型设计.............................................................................................................12 2.2.1 几何模型..........................................................................................................12 2.2.2 力学模型..........................................................................................................15 2.2.3 数值模型..........................................................................................................16 2.3 数值模拟过程.............................................................................................................17 2.4 数值模拟结果与分析.................................................................................................17 2.4.1 沿工作面走向顶板采动特征..........................................................................17 2.4.2 沿工作面倾向顶板采动特征..........................................................................23 2.4.3 工作面顶板结构特征......................................................................................27 2.5 本章小结.....................................................................................................................27 3 工作面顶板结构特征物理相似模拟....................................................................................29 3.1 相似模拟原理.............................................................................................................29 3.2 实验内容及目的.........................................................................................................29 3.3 工作面走向平面模拟实验.........................................................................................30 目 录 II 3.3.1 模型尺寸选择及参数计算..............................................................................30 3.3.2 模型顶部载荷及支架初撑力计算..................................................................31 3.3.3 监测仪器及方法..............................................................................................32 3.3.4 相似材料制作及模型铺装..............................................................................34 3.3.5 模型开挖..........................................................................................................34 3.3.6 实验现象分析..................................................................................................34 3.3.7 实验结果..........................................................................................................36 3.4 工作面倾向平面模拟实验.........................................................................................38 3.4.1 模型尺寸选择及参数计算..............................................................................38 3.4.2 支架初撑力计算..............................................................................................38 3.4.3 监测仪器及方法..............................................................................................39 3.4.4 相似材料制作及模型铺装..............................................................................40 3.4.5 模型开挖..........................................................................................................40 3.4.6 实验现象分析..................................................................................................41 3.4.7 实验结果..........................................................................................................43 3.5 工作面三维立体模拟实验.........................................................................................45 3.5.1 模型尺寸选择及参数计算..............................................................................45 3.5.2 模型加载..........................................................................................................45 3.5.3 监测仪器及方法..............................................................................................45 3.5.4 相似材料制作及模型铺装..............................................................................46 3.5.5 模型开挖..........................................................................................................47 3.5.6 实验结果..........................................................................................................49 3.6 本章小结.....................................................................................................................50 4 工作面基本顶断裂岩块结构特征........................................................................................52 4.1 顶板岩层断裂特征.....................................................................................................52 4.1.1 岩板模型..........................................................................................................52 4.1.2 岩板模型受力分析..........................................................................................54 4.1.3 岩板的极限跨距..............................................................................................58 4.1.4 基本顶初次断裂特征......................................................................................60 4.1.5 基本顶周期断裂特征......................................................................................62 4.2 顶板倾向砌体结构特征.............................................................................................64 4.2.1 倾向砌体结构模型..........................................................................................65 4.2.2 倾向砌体结构受力分析..................................................................................66 4.2.3 倾向砌体结构稳定性分析..............................................................................69 目 录 III 4.3 本章小结.....................................................................................................................70 5 工作面覆岩承载拱结构特征................................................................................................72 5.1 承载拱结构模型.........................................................................................................72 5.1.1 拱结构相关理论..............................................................................................72 5.1.2 承载拱结构形成的条件..................................................................................73 5.1.3 工作面走向承载拱结构模型..........................................................................73 5.1.4 工作面倾向承载拱结构模型..........................................................................74 5.2 承载拱结构力学分析.................................................................................................75 5.2.1 工作面走向承载拱支座反力和内力计算......................................................75 5.2.2 工作面倾向承载拱支座反力和内力计算......................................................79 5.3 承载拱结构合理拱轴线计算.....................................................................................83 5.3.1 走向承载拱结构合理拱轴线..........................................................................83 5.3.2 倾向承载拱结构合理拱轴线..........................................................................84 5.4 承载拱结构稳定性分析.............................................................................................87 5.4.1 承载拱结构的平衡稳定性分析......................................................................87 5.4.2 承载拱结构的强度稳定性分析......................................................................88 5.4.3 承载拱结构稳定性控制方法..........................................................................89 5.5 本章小结.....................................................................................................................90 6 工作面矿山压力现场观测....................................................................................................91 6.1 矿压观测的目的及意义.............................................................................................91 6.2 矿压观测的内容和方法.............................................................................................91 6.2.1 矿压观测的内容.......................