煤柱下巷道的应力敏感性分区特征及响应机制.pdf

国家自然科学基金项目（51574227） 国家自然科学基金项目（51474209） 博士学位论文 煤柱下巷道的应力敏感性分区特征及响应 机制 Stress Sensitivity Zoning Characteristics and Response of Roadway under Coal Pillar 作 者康继忠 导 师柏建彪 教授 中国矿业大学 二○一六年十月 万方数据 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 煤柱下巷道的应力敏感性分区特征及响应机制 Stress Sensitivity Zoning Characteristics and Response of Roadway under Coal Pillar 作 者 康继忠 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 评 阅 人 二○一六年十月 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 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 致谢 转眼间，博士三年半的生活即将画上句号，尽管不完美，但己竭尽全力。其 实确切的说是分号，是学生阶段后的一个分隔符。虽然博士毕业，但自己距恩师 期冀仍有巨大差距，这也督促自己在一个工作阶段朝恩师所定目标努力前行。 这三年半里，在导师柏建彪教授的引导下，我收获颇丰，感触亦深。柏建彪 教授渊博的知识积累、开阔的学术视野、严谨的治学态度、优秀的做人品质和认 真的工作态度深深地影响了我，这将是我一生为之奋斗的榜样。导师从一开始对 我高标准的严格要求， 让我的博士研究生学术生涯充满压力和竞争的同时也收获 满满，这也是我一生当中最为宝贵的经历和财富。 这三年半里，导师柏建彪教授给予我无私的指导和帮助。学习中他悉心传授 知识，授业解惑；生活中他关怀备至，虽日理万机，却时常关心我们的学习和生 活。在论文的整个研究过程中，柏老师在论文选题上给予了高瞻远瞩的指导，在 技术路线的设计上给予了高屋建瓴的点拨， 在论文的框架结构以及遣词造句上给 予了匠心独运的指导。论文从选题到成稿，一字一句无不饱含着导师的心血与智 慧。没有导师的悉心指导和帮助，论文是不可能得以顺利完成的。值此毕业论文 完成之际，我心怀感激和敬佩，感谢柏老师在研究生期间对我孜孜不倦的教诲和 无私帮助与关怀，在此对导师柏建彪教授致以崇高的敬意和由衷的感谢，也要感 谢导师及师母在生活、做人、做事上给予的启示和帮助。 感谢课题组王襄禹教授、徐营副教授和陈勇、闫帅老师，学习、工作中他们 是让我尊敬的老师，生活中他们是我的兄长和朋友。论文写作过程中，他们不厌 其烦的指导我修改论文并给我很好的建议和指正， 在这里我向他们道一声辛苦和 感谢 感谢课题组张自政博士、 神文龙博士对论文中数值模拟的指导以及疑难问题 的解答。感谢孙毅硕士、赵志勇硕士、申晓辉硕士以及各位好友对论文纰漏的指 正和细节完善方面的指导，我们共同学习进步，生活中互相关心鼓励，愿友谊经 久不衰。 感谢父母，他们给我生命、养育我长大、教我做人，在我心烦气躁时给予理 解和包容，并安慰和鼓励，他们是我坚实的后盾，不断奋斗的动力。 最后，感谢各位专家和教授在百忙之中评审本文，并期待得到更多的指导和 启迪。 康继忠 2016 年 10 月 16 日 万方数据 I 摘摘 要要 近距离煤层群下行开采存在大量遗留煤柱， 遗留煤柱底板极易出现高应力集 中、应力空间非均匀分布现象。下位煤层巷道穿越上部遗留煤柱时，巷道围岩极 易出现大变形破坏甚至冲击矿压等动力灾害，严重影响下位煤层正常高效开采。 因此，本文以鑫瑞煤矿为研究背景，结合近距离煤层工程地质条件，综合采用现 场测试、理论分析、数值计算、工业性试验等方法，提出用“应力三指标（集中 系数、应力梯度、侧压系数） ”描述煤柱底板应力分布状态，研究了煤柱底板应 力三指标分布演化规律及其对巷道围岩稳定性影响规律， 提出了近距离煤层群下 行开采下位煤巷布置原理及控制技术。 （1） 建立了煤柱内支承应力分布模型， 计算推导了煤柱内支承应力解析解。 提出用应力三指标描述煤柱底板应力分布状态，构建了单煤柱、双煤柱及煤柱群 底板应力三指标弹性解析模型， 建立了应力三指标与垂直间距及水平错距间的关 系模型，揭示了应力三指标空间分布规律。 （2）研究了下位煤层工作面采动应力对应力三指标的作用规律，揭示了采 空区下、采空区与煤柱交界下、煤柱下应力三指标分布演化规律，提出了下位煤 层区段煤柱宽度设计方法，确定了鑫瑞煤矿合理的区段煤柱宽度。 （3）研究了应力三指标对巷道稳定影响协同作用规律，发现巷道稳定性随 应力集中系数、应力梯度增加而减小，当侧压系数小于 1 时，侧压系数对巷道稳 定性影响较小，当侧压系数大于 1 时，巷道围岩稳定性随侧压系数增加而减小； 应力集中系数较大时， 围岩稳定性受应力梯度及侧压系数影响的敏感度显著提高； 应力梯度较大时，围岩稳定性受侧压系数影响的敏感度显著提高；据此，提出下 位煤巷布置应力三指标安全阈值的概念及确定方法。 （4）基于遗留煤柱下应力三指标分布演化规律，结合应力三指标对煤巷稳 定性影响规律，提出了下位煤层回采巷道布置方法，提出了将下位回采巷道分为 三类即采空区下、采空区与煤柱交界下、煤柱下巷道，并确定了各自的围岩稳 定控制技术。 （5）将研究成果应用于鑫瑞煤矿平均层间距为 3.25m、并穿越遗留煤柱的 下位煤层回采巷道，现场试验效果表明，研究确定的巷道布置及支护技术有效地 控制了巷道围岩变形。 论文有图 97 幅，表 9 个，参考文献 161 篇。 关键词关键词近距离煤层；遗留煤柱；应力集中系数；应力梯度；侧压系数；分 区特征；采动应力；巷道布置；支护技术 万方数据 II Abstract Many residual coal pillars exist in upper parts of closed distance seam group during the process of descending coal mining, of which the floor is likely to appear high stress concentration and uneven distribution of stress space. When roadway below the coal seam vertically passes through the upper remained coal pillars, it is possible to arise large deation of surrounding rock and impulsion pressure of other power disaster, seriously affecting the normal and efficient coal seam mining. Therefore, based on Xin Rui Colliery, combining with engineering geological conditions of close coal seam, this paper is using a combination of field research, theoretical analysis, numerical simulation, mining pressure monitoring and other means to study the evolution law of abnormal stress distribution in the floor of remained coal pillars and its influence on the stability of surrounding rock synergy law, putting forward the following coal roadway arrangement and the principle of dynamic control during the process of descending mining in closed distance seam group. The bearing stress distribution model inside coal pillar is established, and the analytical solution of bearing stress is deduced. Using “three inds of stress” including the concentration factor, stress rate, lateral pressure coefficient to describe the floor surrounding rock stress state of residual bearing coal pillars, we construct abnormal stress flexible analytical model of surrounding rock in single pillar, dual pillar and pillar group, reveal the spatial distribution law and influencing area of stress concentration factor, stress rate and lateral pressure coefficient. The influencing law of “three inds of stress” caused by the mining of lower working face is studied, the evolution law of “three inds of stress” below goaf, below the junction between the goaf and coal pillars, below coal pillars is revealed, the design of pillar width in the lower coal seam is put forward, and the reasonable pillar width is determined according to specific condition of Xinrui Mine. The synergy law of roadway stability affected by “three inds of stress” is studied, we find that the concentration factor and stress changing rate inversely affect roadway stability. When the lateral pressure coefficient is less than 1, lateral pressure coefficient has less influence on roadway stability. When it is more than 1, it affects roadway surrounding rock stability inversely. High concentration factor can significantly enhance the influence that stress changing rate and lateral pressure coefficient affect roadway stability, high stress changing rate can also strengthen the influence. So we propose the concept and determination of “three inds of 万方数据 III stress” in the lower coal roadway. Based on distribution and evolution law of “three inds of stress” in the residual coal pillars, combining with the synergy law of roadway stability affected by “three inds of stress”, a reasonable principle of lower mining roadway arrangement is put forward, lower mining roadway is divided into three types gateroad below goaf, below the junction between the goaf and coal pillars, below coal pillars, each roadway surrounding rock control technology is determined. Research result is applied into a lower mining gateroad intersecting remained pillar with layer spacing of 3.25m in Xinrui Mine, field investigation indicates that roadway layout and support technology effectively control the deation of roadway surrounding rock. The thesis has 97 graphs, 9 s and 161 references. Keywords closed distance seam; remained coal pillars; concentration factor; stress changing rate; lateral pressure coefficient; Zoning characteristics; mining abutment stresss; entry layout; support technology 万方数据 IV Extended Abstract In this paper, by taking coal roadway under closed residual coal pillars as research project, combining with the specific geological conditions of 15101 transporting gateway in Xin Rui colliery, on the basis of domestic and foreign scholars, combination of theoretical analysis, numerical simulation and industrial site are used to study the essential characteristics of roadway deation and failure under closed residual pillar, and to put forward the corresponding control principle and the development of targeted control technology. 1 The analysis of bearing properties of coal pillars and abnormal stress field in the floor Based on limit equilibrium theory, a of mechanics resolution is used to discuss coal bearing characteristics on one side of goaf or excavated roadway, which fixes the width of limit equilibrium zone, proposes the bearing stress function model of different bearing properties of coal pillars, establishes bearing stress function solution of bimodal bearing pillar. Combining with elasticity, we construct abnormal stress flexible analytical model of surrounding rock in single pillar, dual pillar and pillar group, reveal the spatial distribution law and influencing area of stress concentration factor, stress rate and lateral pressure coefficient. 1 Bearing properties of coal pillars there are actually two states of stress equilibrium carrying in shallow plastic coal the limit equilibrium state and non- equilibrium limit state. In the limit equilibrium state, coal bearing stress equals to its own limit bearing stress. In non-equilibrium limit state, coal bearing stress is less than the limit bearing stress, but it is still in the stress equilibrium. Based on this, it is assumed that coal in goaf-side is in a non-equilibrium limit state, then we analyze coal bearing properties in goaf-side and find that coal in goaf-side tends to be more non- equilibrium limit state. On this basis, a modified model of limit equilibrium zone of coal in goaf-side is established, a modified coefficient of limit equilibrium zone is proposed, the law of mining depth, stress concentration factor of surrounding rock, damaged condition of coal and the degree of stability of coal-rock interface affecting it is analyzed, the width analytical solution of actual plastic bearing zone is exported. 2 Function solution of bearing stress in coal pillars Based on the actual coal bearing properties in goaf-side, a function model of bearing stress of coal in goaf-side is established A linear model is simplified in plastic zone, an exponential function model is simplified in elastic zone, which preferably reveals the distribution law of 万方数据 V bearing stress of coal in goaf-side; By combining with the width of plastic bearing zone of coal in goaf-side, coal pillars are divided into pillars of a single peak yielded and pillars of elastoplastic double peaks. Combining with the specific geological conditions of Xin Rui colliery, we find that residual coal pillars all belong to a bimodal elastoplastic type, and we define interaction coefficient of bearing stress of coal pillars at both empty sides, establish peak stress concentration factor of coal pillars, and carry out mathematical model to solve bearing stress of pillars of elastoplastic double peak. 3 Stress concentration factor under pillars Combining with elasticity, to establish the solution model of floor bearing stress under single-pillar. The integral principle was used to solve the analytic solution of floor bearing stress under double pillars and pillar group. Numerical results and theoretical solution exhibit the same law of stress field distribution. Based on this, the analytic solution of high stress concentration factor is established between single pillar and double pillars and pillar groups of elastoplastic double peaks, the following high stress concentration zone is divided. Based on the specific engineering geological conditions, it was found that the maximum scope of high stress concentration area is 30m 44m horizontal vertical under a single pillar, which is 43m 45m under double pillars and 108m 48m under pillar groups. 4 Stress rate under pillar Based on differential principle, the rates of floor vertical stress, horizontal stress and shear stress that change as horizontal position changes are revealed under single pillar, double pillars and pillar groups. Low stress rate is appeared under elastic pillar nucleus and goaf, high stress rate and stress peak are appeared at the goaf-pillar junction and plastic pillar. As interlayer spacing increases, stress rate decreases and the influencing area of high stress rate becomes as 0m 30m interlayer spacing. 5 Side pressure coefficient under pillar the distribution law of side pressure coefficient is analyzed under single pillar, double pillars and pillar groups, which is less than 1 column. Side pressure coefficient is greater than 1 at the pillar-goaf junction, where appears side pressure coefficient peak. With an increase in interlayer spacing, the value of peak decreases, the peak position moves away from the edge of the pillar. When interlayer spacing reaches 30m, side pressure coefficient peak disappears and the maximum value appears under roadway. The value is much larger than it at the pillar- goaf junction and the rate of decay is the maximum as interlayer spacing increases. 2 The influencing law that the mining of lower working face affects abnormal 万方数据 VI stress field The mining disturbance of lower coal seam will lead to redistribution of stress field under the residual pillar, of which the stress superposition will cause the redistribution of abnormal stress field in the second chapter. Numerical s was used to reproduce the space-time influencing law of abnormal stress field under the residual pillar caused by the mining of lower working face. 1 Advanced stress concentration factor ① Vertical stress concentration factor under pillar show the change law of slow, rapid, slow increase then steady. It increases from 2.34 to 3.25, the influencing area advances the mining face from 0m to 50m. ② Vertical stress concentration factor under the junction of pillar and goaf changes little, stable between 0 and 0.3; ③ Vertical stress concentration factor under the goaf shows a tendency of gradual increase, sudden decrease in mutation. The largest increase is 1 to 2.62, the influencing area is in front of working face from 10m to 40m. When it is 10m away from working face, the mutation decreases to 1. ④ Horizontal and vertical stress concentration factor have similar change law, except the absolute size. 2 Advanced stress rate ① The average changing rate of vertical stress of surrounding rock below the goaf and pillar edge is greater than 0. It shows a law of linear increase then decrease in front of working face 50m. The maximum rate is 0.3MPa / m that appears in front of working face 12m. ② The average changing rate of vertical stress of surrounding rock just below the goaf and pillar is less than 0, which decreases rapidly absolute value increases then stabilizes in front of working face 55m. The minimum rate is -1.3MPa / m that appears in front of working face from 0m to 18m. 3 Advance side pressure coefficient ① Side pressure coefficient under goaf is less than 1. It reduces to a lesser extent in front of working face 90m, with a slow decreasing trend. ② Lateral pressure coefficient under pillar and goaf has a similar evolution. It floats within 30m away from working face, the overall changing value is small. ③ Lateral pressure coefficient at the junction of bottom pillar and goaf is more than 3. It decreases linearly, increases linearly and decreases in front of working face 100m. The