特厚煤层坚硬顶板破断动载特征及巷道围岩控制研究.pdf

博士学位论文 特厚煤层坚硬顶板破断动载特征及 巷道围岩控制研究 Dynamic Characteristic of Hard Roof Fracture in Extra-thick Coal Seam and Its Application on the Control of Roadway Surrounding Rock 作 者于 洋 导 师柏建彪 教授 中国矿业大学 二○一五年五月 国家自然科学基金项目（51174195） 江苏省高校优势学科建设工程资助项目（PAPD） 中图分类号 TD823 学校代码 10290 UDC 622 密 级 公开 中国矿业大学 博士学位论文 特厚煤层坚硬顶板破断动载特征及 巷道围岩控制研究 Dynamic Characteristic of Hard Roof Fracture in Extra-thick Coal Seam and Its Application on the Control of Roadway Surrounding Rock 作 者 于洋 导 师 柏建彪 申请学位 工学博士 培养单位 矿业工程学院 学科专业 采矿工程 研究方向 矿山压力与岩层控制 答辩委员会主席 窦林名 评 阅 人 盲审 二○一五年五月 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 论文审阅认定书论文审阅认定书 研究生于洋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 致谢致谢 经过了废寝忘食、挑灯夜战的煎熬，论文终于写到了最后一页，这一页可能 是我六年研究生历程中最期待的一页， 不是因为写完这一页我二十四年的学生生 涯即将正式落幕， 而是因为我实在是迫不及待地想借这张纸向所有帮助过我的人 们表示感谢。 写到这里，脑海中浮现了太多学生时代的回忆我想到了小学时学习成绩徘 徊在中下游，却整天梦想驰骋在绿茵场上；我想到了初中时学习成绩和运动赛场 全线飘红，从此背负了所谓全能的压力；我想到了高中时高考发挥失常、屡败屡 战，老师同学叹息无奈的眼神；我想到了金榜题名时父母激动的泪水和亲人朋友 羡慕的目光；我想到了大学时卧薪尝胆，靠着严于律己的信念，最终化茧成蝶、 完美蜕变；走过大学，原本我的学生生涯应该和绝大多数同学一样华丽落幕，开 启另一段人生旅程；然而，因为我特殊的人生履历和对大学的无比珍惜，让我无 论如何都不能就此结束这段弥足珍贵的经历。为了不留遗憾，我用自己大学四年 努力换来一张研究生录取通知书，而从那一刻开始，我的人生也进入了一个全新 的轨迹，真正完成了从体育生到研究生的蜕变，这种全新的生活与挑战不是因为 我厌倦了过去，而是因为有您 因为有您我的导师柏建彪教授，是您当年的肯定和支持，让我有机会来 到了全世界顶尖的采矿工程系学习成长， 有机会发表了属于自己的第一篇学术论 文，有机会走进煤矿千米深邃的巷道发出自己的声音。犹记得第一次与您一起探 讨学术与专业问题的紧张与兴奋； 第一次与您一起出差下井解决现场实际问题时 的茫然与恐惧。还记得多少次您找我谈心，帮我分析自身的缺点与不足，直言不 讳我的浮躁与稚嫩，这一切都成了宝贵的财富；更记得我家庭出现变故时，电话 那头传来您坚定的支持与鼓励，让我没有向困难低头，越挫越勇，重新振作。有 您这样好的恩师，不言感谢，还能言何呢 因为有您我的老大王襄禹老师，在过去六年的研究生经历中，您不仅教 会了我专业与技艺，让我从一个采矿工程的门外汉逐步成长成可以独当一面博 士， 更教会了我如何做人如何处事， 让我的人生收获了更多原本不属于我的精彩。 第一次出差、第一次设计、第一次报告、第一次独立下井太多太多的第一次 都是在你的教导与关心下完成，让我不断成长进步。有您这样好的老大，不言感 谢，还能言何呢 因为有您徐营老师、陈勇老师、闫帅老师，作为我们整个团队的骨干成 员，也是采矿界的未来之星，你们都在我的学习生涯的不同阶段悉心帮助过我， 让我在专业和生活等各个方面都在不断完善。 有你们这样好的领路人， 不言感谢， 还能言何呢 因为有您陈科师兄、朱琪师兄、胡忠超师兄、李磊师兄、李文峰师兄、 许磊师兄、刘洪林师兄、张永杰师兄。如果说刚才提到的各位老师都是高大上的 学术权威，而这些师兄则更是接地气的好心大哥。各位师兄不但在专业上技艺精 湛，更是在平时的工作学习与生活中给予我太多的关爱与照顾，让我能够认清自 己的方向，努力向他们学习，做的更好更出色。有这样的好大哥，不言感谢，还 能言何 因为有您王猛、赵家巍、邱亮亮、安浩键、廉常军、薛广哲、朱才坤、 张自政、神文龙、刘洋、严冬、李赟、李思超、武立飞、吴明明、朱子祺、王若 帆、孙毅、崔昊、李国杨。客观地讲，如果没有你们，也就不会有这篇论文的付 梓出炉，正是你们在实验技术、理论计算、数值分析、软件绘图、数据分析、采 集数据和文章排版等方面的全程帮助指导， 才让我一个完全基于零基础的科研民 工有了属于自己的科研课题，也才有了今天借这本论文表达心中感谢的机会，正 是你们的体谅与分担， 让我能够更好地在科研和实践工作中踏实稳健地走好自己 得每一步道路。有这样得好伙伴，不言感谢，还能言何 因为有您曾经在前进道路上帮扶我的人我的启蒙教练刘军、曹建国， 虽然我没有最终走上梦想的绿茵赛场，但是那段训练场和比赛场上的峥嵘岁月， 是我永生难忘的记忆，也是我一辈子的精神财富；我的良师益友山东科技大学刘 立民教授、泰安方舟矿业科技有限公司许可经理、曹君陟经理、葛瑞行经理、米 鹏主任，你们不仅让我掌握了矿山支护材料的精髓，让我在现场底气十足，而且 在我最需要帮助的时候慷慨解囊，帮我走出泥潭，重新振作；我的现场指导老师 神华乌海能源有限责任公司郭军总经理， 神华蒙西煤化有限责任公司棋盘井 煤矿郭永红矿长、曹金龙副总工程师、刘鑫工程师、王忠伟工程师，窑街煤电集 团有限公司袁崇亮院长，海石湾煤矿罗万忠矿长、王君得总工程师、薛世智副总 工程师、李国湖副总工程师、陈伟伟工程师、吴占奇组长，吉煤集团辽源矿务局 梅河煤矿宋伟矿长， 江苏省矿业工程集团有限公司孙敦勇处长、 杨海楼总工程师， 蔺润煤矿王越矿长、朱庆庆科长，同煤浙能麻家梁煤业有限责任公司闫磊工程 师感谢你们在煤矿现场给予的支持与帮助， 你们的悉心指导让我的不断积累 自信，快速成长。有这样的前辈朋友，不言感谢，还能言何 因为有您徐州马拉松协会、 中国矿业大学马拉松协会以及许多擦肩而过 的跑者，谢谢你们的鼓励和陪伴让我不断超越极限，在每一个懵懂的黎明，用奔 跑迎接第一缕阳光，跨越一个又一个 42.195 公里的终点；没有人逼迫我跑马拉 松，当我踏上起跑线时，我觉得这是我一生最勇敢的时刻；跑到 30 公里时疲惫 不堪，我觉得这是我一辈子做的最愚蠢的事情之一；但是当我通过终点时，尽管 没有人鼓掌欢呼，但是我还是觉得这是我一生最荣耀的时刻。跑过的路永远不会 欺骗我，人生亦如跑步，我会一直勇敢的跑下去有这样的执着勇者，不言感 谢，还能言何 言了这么多感谢，我想大家可能已经忘了这是我的博士论文，在这么专业严 谨的学术论文面前，煽情太多可能并不合适。然而，在这本论文的最后，请务必 允许我将最饱满、最真挚、最朴素的感谢送给我的父母，过去的几年，由于家庭 的原因，我的父母承受了太多的责任与压力，父亲的病情不断加重，作为家里唯 一的儿子，为了完成学业，为了今天这本论文的顺利付梓，没能在最困难的时候 为家庭分担，内心的愧疚与不安持续在每个不眠之夜。感谢爸妈，是你们的宽容 与理解为我们的家撑起了一片天， 让我在风雨之下的远方仍然能够感受到温暖的 庇护。今天这本论文的完成与其说是归功于我的执着和努力，不如说是你们对儿 子浓浓爱意的浓缩与体现，论文的每一个字记录的不单单是冰冷的实验数据，更 是你们用质朴无华的真情唱给我听的动人音符。从这一刻起，我会把对你们的感 恩与挂念深埋心底，在以后的工作学习中，用出色的成绩来回馈你们的付出。最 后，马上要开启一段新的征程，因为有您爱人廉吉荣的风雨相伴，相信我会 走地更加专注与笃定，感谢你的付出，从今天开始为你而战。 公元二零一五年四月十六日，论文成册，感谢各位陪伴，谨以此文献给所有 帮助过我的朋友 于洋 I 摘摘 要要 朔南矿区是一个新建的特大型矿区，区内煤层厚度大、开采条件复杂，而且 煤层上方赋存有多层坚硬难冒放顶板。在特厚煤层综放开采过程中，采场尤其是 采空区后方的沿空巷道呈现出强烈动力显现特征， 严重威胁到矿井的安全高效生 产。因此，本文以麻家梁煤矿为研究背景，结合井田区域构造特征、煤岩赋存条 件和开采技术要求，综合采用现场调研、理论分析、数值模拟计算、相似材料模 拟实验以及现场实测等研究手段， 系统研究了坚硬顶板条件下特厚煤层综放开采 的矿压显现特征及动载作用机理， 针对性地提出了基于水压致裂弱化控制和抗动 载作用支护系统的沿空巷道围岩控制原理和技术途径。 （1）麻家梁煤矿受到煤岩地质构造特征和开采技术条件的影响，频繁出现 工作面来压强度大、煤壁片帮、支架损坏、沿空巷道强烈位移、支护结构严重破 坏等强烈矿压显现特征。工作面液压支架初撑力普遍不足，基本顶来压步距大、 强度高、动载系数大，并且呈现强弱交替的大、小周期来压规律，采动支承应力 波及范围大、影响程度高，沿空巷道呈现阶段性的动载变形特征。 （2）研究得到了特厚煤层双硬顶板破断方式和垮落步距，指出特厚煤层低 位双硬顶板破断失稳呈现下位“悬臂梁”与上位“砌体梁”结构。在此基础上， 揭示了特厚煤层低位双硬顶板破断失稳是导致采场工作面强矿压显现特征的主 要影响因素。 （3）判定并验证了麻家梁煤矿上覆岩层主关键层的位置，建立了坚硬顶板 破断的动载作用模型， 揭示了下位采场及沿空巷道动载强度与上覆坚硬顶板破断 动载源强度之间的关系， 并分别确定了采场和沿空巷道强烈动载特征的作用机理 和主控岩层。 （4）分析了不同属性、不同方向的动载应力波对巷道围岩稳定性的影响程 度和规律， 提出了动载应力波之间的相互叠加效应导致巷道迎波侧和背波侧出现 拉应力并产生积累损伤和强烈变形，为巷道围岩的危险部位；通过数值计算得到 了巷道围岩分别在有、无支护和动、静载作用条件下的动力响应特征。 （5）研究了不同水压致裂方式的作用效果，提出了坚硬顶板水压致裂弱化 控制技术， 确定了合理的施工工艺和关键参数； 优化了采区巷道布置方式和参数， 建立了以高强蛇形让压吸能锚杆为核心的抗动载支护系统和相应的设计方法， 并 将以上研究技术成功应用于现场工程实践。 该论文有图 133 幅，表 29 个，参考文献 185 篇。 关键词关键词特厚煤层；坚硬顶板；破断规律；应力监测；动载特征；应力波；水压 致裂；弱化吸能 II Abstract Shuonan is a newly constructed mining area characterized by both thick coal seam and complicate geological condition. As there are several hard roofs which are difficult to collapse above the coal seam, the working face and gob-side entry appear strong dynamic characteristics during the mining period, which threatens the safe and highly-efficient production seriously. Based on the regional tentonic characteristics, stratum occurrence conditions and mining technical requirements of Majialiang mine, the dissertation studied systematically the characteristics of strata behavior and dynamic loading mechanism of fully mechanized top-coal caving of extra-thick coal seam by using comprehensive research consisting of on-site survey, theoretical analysis, numerical simulation, physical similar simulation test and on-site monitoring. Then it was put forward that the weakening control principles and technical s based on the hydraulic fracturing techniques and anti-dynamic loading support system. 1 Influenced by geologic structure and mining techniques, many strong characteristics of strata behavior, e.g. high pressure at the working face, coal wall spalling, hydraulic support damage, large deation of gob-side entry, supporting structures broken, frequently appeared. Moreover, the strata behavior were also companied by other features, such as lack of initial hydraulic support resistance, large step and large strength of roof weighting, large dynamic coefficient, switch between big/small periodic weighting, large influencing range of abutment pressure, and periodical dynamic deation characteristics of gob-side entry. 2 Having obtained the caving mode and caving step of double-hard roof in extra-thick coal seam, the study pointed out that the rupture instability of double-hard roof would generate “cantilever beam” and “masonry beam”in below and upper layers respectively. Then the study revealed that the main factor inducing strong strata behaviors at working face was the rupture instability of bottom double-hard roof in extra-thick coal seam. 3 Based on the determination of the main key strata position of Majialiang coal mine, the study established the dynamic load model for the rupture of hard roof and revealed the relationship between dynamic strength of working face and gob-side entry and that of hard roof. Then the mechanism of dynamic load characteristics in working face and gob-side entry and the main controlling strata were determined respectively. III 4 The study analyzed the influences of the property and direction of dynamic stress wave on the stability of roadway surrounding rock. Then it was put forward that the superimposed effects of dynamic stress brought about tensile stress in the heading wave side and back wave side of roadway, which caused the accumulated damage and strong deation. The dynamic response characteristics of roadway surrounding rock under supported/unsupported and static/dynamic conditions have obtained through numerical simulation. 5 By studying the effects of different hydraulic fracture modes, the study put forward the hydraulic fracture weakening control technology for hard roof, and determined the reasonable construction technology and key parameters. The study also optimized the roadway layout mode and parameters, and developed a anti-dynamic support system and related designing by using high strength S-shaped bolt. The above controlling technology has applied into the field engineering successfully. This dissertation includes 132 graphs，37 tables and 185 references. KeywordsExtra-thick coal seam; hard roof; Fracture rules; stress monitoring; dynamic load characteristics; stress wave; hydraulic fracturing; weakening control IV Extended Abstract By using the combined s, such as on-site investigation, theoretical analysis, numerical calculation, similar simulation and field measurements, the dissertation studied the strong dynamic pressure characteristics of full-mechanized caving mining in extra-thick coal seam, rupture laws and dynamic stress effects of hard roof, the response laws of gob-side entry and working face, the hydraulic fracturing weakening controlling mechanism, and reasonable layout of gob-side entry. Based on the above studies, the dissertation obtained the following conclusions 1 Influenced by geologic structure and mining techniques, many strong characteristics of strata behavior, e.g. high pressure at the working face, coal wall spalling, hydraulic support damage, large deation of gob-side entry, supporting structures failure, frequently appeared. The complicate sedimentary environment, active tectonic movement and the energy accumulation of stress field were the geological conditions causing the strong strata behaviors. Besides, the special mining conditions, such as the large working spacing and several hard roofs with features of high strength, long suspension distance, high energy accumulation and potential sudden instability, aggravated the dynamic disasters of working face and gob-side entry. 2 The standard-reaching rate of initial support resistance was less than 20, which caused many negative phenomena like roof broken, coal wall spalling, large roof subsidence in the middle of working face. The first weighting and periodic weighting of basic roof had the features of large step, high strength and obvious dynamic characteristics. The first weighting step and periodic weighting step were 91.61m and 22.5m in average respectively. The average dynamic coefficient was 1.32. The periodic weighting of basic roof switched between small and large periodic weighting. Each large periodic weighting generally consisted of 34 small periodic weighting. 3 Both range and influencing degree of abutment stress induced by full-mechanized caving mining of extra-thick coal seam was large. The influencing range of lateral abutment stress in stable exceeded 45m, and the stress peak was about 26MPa. The influencing range of moving abutment stress was from 80m in front of working to 300m behind the working face. The influencing degree of area behind the working face was larger. The maximum stress rising value exceeded 30MPa. The V gob-side entry appeared staged dynamic load characteristics, and appear “instantaneous displacement” behind working face in scope of 120～150 m. The maximum deation speed was close to 400 mm/d. 4 According to the present roadway layout mode of Majialing coal mine, the width of coal pillar should be 50m at least. If the gob-side entry of below mining section was excavated in forward direction, the position of excavation stopping should be more than 100m ahead of the working face in upper mining section. Once the distance to the back of working face reached 400m, the roadway could be excavated again. If the roadway was excavated in opposite direction, the distance between heading end and working face of upper mining section should be in safe distance 400m. 5 The rupture instability of below level double-hard roof generated “cantilever beam” in the below level and “masonry beam” in the upper level. The initial and periodical caving steps of low level hard roof were about 45m and 15m respectively, while those of top level hard roof were about 110m and 45m respectively. The staged rupture of low level double-hard roof generated the “large and small periodic weighting” and the staged deation characteristics of gob-side entry. As the influencing range of dynamic load was limited, the gob-side entry behind the working face in range of 120m150m will not be damaged by dynamic load. 6 There are six key strata in the overlying rock in Majialiang mine according to theoretical calculation, including two low level inferior key strata 7.8m and 11.6m coarse sandstone, one top level main key strata, and three inferior key strata between them 5.2m siltstone, 5.0m and 8,4m packsand. The observation results on the ground showed that the caving step of main key strata was in the range of 140m180m, which was in accordance with the theoretical results 150.25m, so it is reasonable that the coarse sandstone 17.8m is the main key strata. 7 Based on rock dynamic mechanics, a dynamic load model for hard roof rapture was established, which revealed the inherent relationship between the dynamic strength of working face as well as gob-side entry and the dynamic load source strength of hard roof rapture. The dynamic strength of working face as well as gob-side entry was mainly influenced by the lithology and thickness of hard roof. If the lithology was identical, the cumulative thickness of hard roof is the main factor. 8 The caving instability of hard roof has dynamic loading mechanisms for stope and gob-side entry. The stope is mainly affected by dynamic effect derived from VI the caving instability of front fracture line of hard roof ①～⑥ and rear fracture line of hard roof ①②. The later one, which is the main key strata for the strata behavior of stope, has a relative high influencing degree. The gob-side entry is mainly influenced by dynamic effects resulted from the hard roof fracture of hard roof ①～ ⑥. Hard roof ⑥ is the main key strata inducing the strong strata behaviors of gob-side entry, and its fracture instability is the main factor causing the strong dynamic characteristics of god-side entry behind the working face in the range of 120150m. 9 The reasonable parameters of dynamic stress wave have been determined. The maximum influence of dynamic stress wave on the stability of roadway surrounding rock is the amplitude and the minimum is the lasting time