煤矿矸石压实力学特性及其在充填采煤中的应用.pdf

博士学位论文 煤矿矸石压实力学特性 及其在充填采煤中的应用 Compaction Properties of Gangue and Its Application in Backfilling Coal Mining 作 者刘 展 导 师缪协兴 教授 中国矿业大学 二 O 一四年六月 万方数据 中图分类号 TD325 学校代码 10290 UDC 密 级 公开 国家重点基础研究发展计划（973）项目（2013CB227900） 国家自然科学金委员会与神华集团有限责任公司联合资助项目（U1261201） 国家科技支撑计划项目（2012BAB13B00） 高等学校学科创新引智计划（111 计划）项目（B07028） 中国矿业大学 博士学位论文 煤矿矸石压实力学特性 及其在充填采煤中的应用 Compaction Properties of Gangue and Its Application in Backfilling Coal Mining 作 者 刘 展 导 师 缪协兴 教授 申请学位 工学博士 培养单位 深部岩土力学与地下 工程国家重点实验室 学科专业 工程力学 研究方向 采动岩体力学与工程 答辩委员会主席 朱珍德 评 阅 人 二○一四年六月 万方数据 130 学位论文原创性声明学位论文原创性声明 本人郑重声明所呈交的学位论文煤矿矸石压实力学特性及其在充填采煤中的 应用 ，是本人在导师指导下，在中国矿业大学攻读学位期间进行的研究工作所取得 的成果。据我所知，除文中已经标明引用的内容外，本论文不包含任何其他个人或集 体已经发表或撰写过的研究成果。对本论文的研究做出贡献的个人和集体，均已在文 中以明确方式标明。本人完全意识到本声明的法律结果由本人承担。 学位论文作者签名 年 月 日 万方数据 学位论文使用授权声明学位论文使用授权声明 本人完全了解中国矿业大学有关保留、使用学位论文的规定，同意本人所撰 写的学位论文的使用授权按照学校的管理规定处理 作为申请学位的条件之一， 学位论文著作权拥有者须授权所在学校拥有学位 论文的部分使用权，即①学校档案馆和图书馆有权保留学位论文的纸质版和电 子版，可以使用影印、缩印或扫描等复制手段保存和汇编学位论文；②为教学和 科研目的，学校档案馆和图书馆可以将公开的学位论文作为资料在档案馆、图书 馆等场所或在校园网上供校内师生阅读、浏览。另外，根据有关法规，同意中国 国家图书馆保存研究生学位论文。 （保密的学位论文在解密后适用本授权书） 。 作者签名 导师签名 年 月 日 年 月 日 万方数据 论文审阅认定书论文审阅认定书 研究生 刘展 在规定的学习年限内， 按照研究生培养方案的要求， 完成了研究生课程的学习， 成绩合格； 在我的指导下完成本学位论文， 经审阅，论文中的观点、数据、表述和结构为我所认同，论文撰写格 式符合学校的相关规定， 同意将本论文作为学位申请论文送专家评审。 导师签字 年 月 日 万方数据 致致 谢谢 本文是在导师缪协兴教授的悉心指导下完成的，从研究方向的确定，到论文 的选题、整体框架的完善、撰写和修改的过程中，都凝聚了导师大量的心血。师 从五载， 获益良多， 感触亦深， 缪老师正直优秀的品格， 深厚而宽广的专业功底， 严谨求实的治学态度，忘我的工作精神，雷厉风行的作风，对科学问题与工程需 求的宏观把握，无不散发着强大的个人魅力，是学生终身学习的典范。感谢缪老 师，不但为我提供了一个良好的科学与工程紧密结合的科研平台，营造了团结、 向上、自由的学习和研究氛围，而且在生活上给予了无微不至的关怀。缪老师的 栽培，学生将铭记终生，在本文完成之际，谨向缪老师致以崇高的敬意和诚挚的 感谢 感谢茅献彪教授在我求学期间给予的关怀与帮助。本文的选题、写作和修改 都得到了茅老师的精心指导与帮助，与茅老师的探讨令学生受益匪浅。在此深深 感谢茅老师为学生的无私付出。 感谢张吉雄教授在工程方面给予的训练与指导， 使我具备了采矿工程的基本 知识，扩展了我在工程问题上的视野。张老师对论文的试验和现场实践等工作给 予了大力支持，使得论文相关工作得以顺利完成。 感谢巨峰讲师、黄艳利讲师和李剑讲师对我的帮助，三位师兄有着旺盛的工 作精力和丰富的项目经验，是我学习的榜样。 感谢张连英教授、 博士生姜海强、 硕士生吴晓刚、 郭记伟、 王东升、 王志平、 康涛、方坤、刘世伟在试验方面，博士生李猛、硕士生李林玥在理论推导方面， 硕士生黄鹏在数值模拟方面，博士生周楠和张强在工程实践方面给予的协助。 感谢力学系所有老师在我求学期间给予的关心和指导。 感谢力学系的兄弟姐妹们和采矿 319 课题组的兄弟们在求学期间给予的帮 助与鼓励，共祝前程远大 感谢硕士生杨光在论文排版与校对中付出的努力。 感谢父母的养育之恩，你们的关爱是我最坚强的后盾，我将带着这份温暖继 续勇敢前行 最后，衷心感谢在百忙之中评审本文的各位专家 万方数据 I 摘摘 要要 综合机械化固体充填采煤是近年来发展起来的新的采煤方法，它将煤矸石、 粉煤灰、建筑垃圾等固体废弃物密实充填至采空区，实现了“三下”压煤等难开 采煤层的高效安全开采，同时，可有效减少或消除煤炭开采引起的地质灾害与环 境污染等问题，是煤炭资源绿色开采的重要研究方向。充填材料（矸石、粉煤灰 等） 的压实特性与充填采煤岩层移动规律研究是实施固体密实充填采煤技术的重 要基础。本文综合采用理论分析、实验测试、数值模拟和现场实测等方法，对煤 矿矸石压实的细观机理、宏观规律、固体充填采煤岩层移动理论等方面进行了系 统的研究，取得了如下主要创新性成果 （1）基于煤矿矸石压实力学特性试验，研究了侧限压实条件下煤矿矸石粒 径级配的分形特征，得到了不同岩性、初始粒径级配的试样在不同压实应力水平 下的分形维数；结合颗粒破碎的分形特征，从能量角度建立了压实过程中试样的 宏观变形与颗粒破碎特征的关系。 （2）研制开发了随机碎石几何模型生成程序 RGM，程序可生成形状随机且 满足指定粒径级配要求的破碎矸石几何模型。通过将 RGM 生成的随机碎石几何 模型模导入颗粒流软件 PFC3d， 建立了不规则颗粒形状的破碎矸石压实数值模型， 实现了 PFC3d 数值模拟中细观力学参数与宏观实验力学参数的有效转换，并进 行了压实特性的数值试验，得到了不同岩性试样的颗粒破碎、压实应变-应力关 系和侧压系数 K0在压实过程中的变化规律。 （3）基于煤矿矸石的压实特性及充填采煤覆岩移动特征，建立了固体充填 采煤岩层移动的双参数 Winkler 地基板模型，分析得到了工作面基本顶的挠度、 弯曲内力和应力分布的解析解， 并给出了充填采煤覆岩不破断的条件及其随充填 材料力学特性参数的变化规律。 （4）成功地将煤矿矸石压实变形规律用于某矿试验充填采煤工作面覆岩移 动规律的数值模拟，得到了工作面覆岩下沉变形、应力分布、塑性区分布及充填 体受力特征随工作面推进距离的变化规律，并与现场实测结果比较，印证了充填 采煤岩层移动双参数 Winkler 地基板模型的合理性。 本文有图 82 幅，表 10 个，参考文献 184 篇。 关键词关键词煤矿矸石的压实特性；固体充填采煤；破碎岩体的随机几何模型；颗粒 流细观模拟；岩层移动规律；双参数 Winkler 地基板模型 万方数据 II Abstract Fully Mechanized Solid Backfilling Coal Mining FMSBCM is a new coal mining well developed in recent years. FMSBCM fills solid waste such as gangue, fly ash, construction damp, etc. densely into goaf, so that the coal whitch is difficult to mine in conventional s e.g. coal under buildings, water bodies and railways can be extracted safely and effectively, and the problems caused by coal mining such as geological disasters and environmental pollution, etc. can be reduced or prevented, those advantages make FMSBCM a major research area in Green Coal Mining. Compaction properties of backfill materials e.g. gangue and fly ash, etc. and strata movment in backfilling coal mining is an important basis of implementing FMSBCM technology. In this dissertation, s of theoretical analysis, experimental test, numerical simulation and field measurement are comprehensively used to systematically research the meso-scale mechanism, macro-scale laws in gangue compaction and theory of strata movement in FMSBCM, and the innovative achievements are as follows 1 Based on the compaction tests of gangue, the fractal breakage of gangue grains in lateral confined compaction was studied, and fractal diemsions of size gradation with different lithologies, initial gradations, and stresses were gainded; by taking consideration of fractal crushing, the relation between grain breakage and macro deation was established from the aspect of energy dissipation. 2 Random Gravel Model RGM, a program to randomly generate geometric model of accumulated gravel grains with given size gradation, were developed based on computational geometry. Crushed gangue samples with irregular shaped grains were modeled in the Particle Flow Code software PFC3d by importing the random geometric models generated by RGM program, and the effective conversion of mechanical parameters from macro-scale to meso-scale were realized, then the numerical compaction tests were implemented, and laws of grain breakage, strain-stress relation and lateral pressure coefficient K0 with different lithologies were obtained. 3 The double-parameter Winkler foundation supported plate model of strata movement in FMSBCM were established based on gangue’s compaction properties and characteristics of strata movement in bacfilling coal mining. The analytical solutions of deflection, internal bending loads and stress distributions of backfilling 万方数据 III coal mining panel’s main roof were calculated, and the condition which maintain overlaying strata don’t breake and its varation with compaction properties of backfilling material was derived. 4 Compaction strain-stress ralations of gaungue were successfully used in numerical simulation of bacfilling coal mining panel’s strata movement of a coal mine, and the overlying strata subsidence, stress distribution, plastic zone distribution and stress within bacfill during the retreaing of the face were simulated, and comparasion of numerical and field measured results proves rationality of the double-parameter Winkler foundation supported plate model of strata movement in FMSBCM. This dissertation contains 82 figures, 10 tables and 184 references. Keywords Compaciton properties of gangue; solid backfilling coal mining; random geometric model of gravel; particle flow based meso-scale simulation; strata movement laws; double-parameter Winkler foundation supported plate model 万方数据 IV Extended Abstract Compaction properties of backfill materials e.g. gangue and fly ash, etc. and strata movment in backfilling coal mining is an important basis of implementing Fully Mechnized Solid Backfilling Coal Mining FMSBCM technology. Systemecall researches were carried out by comprehensively using s of theoretical analysis, experimental test, numerical simulation and field measurement in this dissertation from two major aspects relation between meso-scale mechanism and macro-scale laws of gangue’s compaction and application of gangue’s compaction properties in FMSBCM strata movement analysis. Main achievements are as follows 1 Standard rock mechanical tests of intact gangue and compaction tests of crushed gangue were carried out, and the results indicate that strain firstly increases rapidly, then slowly and finally tardily with increase of stress; size gradation doesn’t obviously affect the strain of crushed sand stone, while crushed sand-mud stone and coal’s strains are notably affected by size gradation, and the larger grain size, the larger strain; mannuly crushed samples with grain size ranges from 2.50-50mm have small strains, and the strains are only larger than samples with 2.50-16mm grains. 2 All of the crushed samples’ accummulated size gradations yield to fractal distributions during lateral compaction, and the mannul crushed samples’ gradations also show fractal characteristics before compaction. All of the samples’ fractal dimenstions D of size gradation ranges from 0.352-2.654, and D decreases with the increase of grain’s strength. All of the samples’ D increase with stress, and tend to about 2.5, whitch indates that all of the samples’ grain size distributions tend to be similar with increase of stress. According to fractal crushing characteristics of the samples during compaciton, ralation between meso-scale mechanism and macro-law of compaction was established from the aspect of energy disspation. 3 Based on the analysis of computational geometry algorithms, a Random Gravel Model RGM genertation program whitch includes 2d and 3d versions is develped. RMG program reproduces gravel grain randomly by convex polyhedron or convex polygon with a presice definition of grain diameter, and generates accumulated gravels geometry with given size distribution by randomly packing grains into model space. The program was developed with consideration of rock-soil mixture, so its application can be extended to generation of random geometricl model of mixed bacfill materials such as gangue/slag-fly ash/aeolian sand/loess mixtures. 万方数据 V 4 Crushed gangue samples with irregular shaped grains were modeled in the Particle Flow Code software PFC3d by importing the random geometric models generated by RGM program, and meso-sacle parameters were calibrated based on standard rock mechanical tests. The particle DEM simulation indicates cluster breakage starts at a low stress whitch more less than the uniaxial compressive strength, even tensile strength of the intact rock samples, because of the ramdom hetergenious distribution of contact chains. The macro-scale strain, breakage ratio of bonds and lateral pressure coeffecient K0 vary in the similar way firstly increase slowly, then grow faster and finally slow down. Breakage notably affects the macro-scale compaction properties of the samples the sample with larger average grain size and lower grain strength has a higer breakege ratio and a larger compressive strain. Macro-scale shearing strength’s decrease caused by breakage results in a increase of lateral pressure coeffecient. Particle DEM simulation can reproduce the tendancy of variation of compaction strain-stress relation, and a good regularity can be observed from results of different samples, that provides more directive evidences for understanding compaction process from meso-scale aspect. 5 Based on the analysis of compaction test results of cushed gangue, taking consideration of tamping by hydraulic powered backfilling coal mining support, the tamped dense backfill’s compaction strain-stress relation was derived from the one obtained by tests. The dense backfill’s compaction strain-stress relations were fited with double-paremeter Winkler foundation model, and the results show high correlations. 6 Double-parameter Winkler foundation supported plate model with all edges fid for main roof deation in backfillin coal mining was established, and solved by the minimum potential energy principle with a trigonometric series ed deflection interpolation function. The analytical solutions of deflection, internal bending loads and stress distributions of backfilling coal mining panel’s main roof were calculated, and the condition which maintain overlaying strata don’t breake and its varation with compaction properties of backfilling material was derived. Take 13120 panel of Pingdingshan No.12 coal mine as an engineering case, the model gives a predicted filling ratio of 87.42 and indicates that no break occure after backfilling coal mining. The model directly links compaction properties of dense gangue backfill and strata movement through double-parameter Winkler foundation, so the difficulty 万方数据 VI of assigning parameter to linear foundation in conventional models is eliminated. 7 Strata movement under backfilling coal mining in 13120 panel of Pingdingshan No. 12 coal mine was simulated with FLAC3d software. In the simulation, backfill’s bulk modulus and shearing modulus were updated forthwith to simulate the compaction properties. Simulation results show that backfilling coal mining prevents the main roof’s break effectively and failure of immediate roof can be reduced, so intact onverlying strata can be maintained. After completely retreating of the panel, the maximum subsidence of immediate roof is 490mm, corresponding a minimum filling ratio of 85.15. 8 According to field measurement results of 13120 panel, both roof subsidence and vertical stress within backfill during the face’s retreating vary in three stages slow growth, uni increase and steady, and the three stages of roof subsidence and vertical stress have a good correspondece, indicating no failure occures during the face’s retreating. The maximum subsidence of immediate roof after mining of the panel is 391mm and the corresponding minimum filling ratio is 88.15. Comparsions among results obtained from double-parameter Winkler foundation supported plate model, numerical simulation and field measurement suggest that both theoretical model and numerical simulation give reasonable conservative results, and predicted results by theoretical model are between those in numercial simulation and field measurement, so the rationality of the theorecitcal model is proved. Keywords Compaciton properties of gangue; solid backfilling coal mining; random geometric model of gravel; particle flow based meso-scale simulation; strata movement laws; double-parameter Winkler foundation supported plate model 万方数据 VII 目目 录录 摘摘 要要........................................................................................................................... I 目目 录录.......................................................................................................................VII 图清单图清单........................................................................................................................ XI 表清单表清单..................................................................................................................... XVI 变量注释表变量注释表 ........................................................................................................... XVII 1 绪论绪论...........................................................................................................................1 1.1 研究背景及意义 ....................................................................................................1 1.2 国内外研究现状 ............................................................................................