【作者】 朱涛；

【导师】 康立勋；

【作者基本信息】 太原理工大学 ， 岩土工程， 2010， 博士

【摘要】 我国煤炭储量丰富,厚煤层储量在我国煤炭总储量中约占44%。因此,厚煤层开采技术在很大程度上决定着我国整个煤炭行业技术研究水平的提高和经济效益的发挥。近十几年来,大采高液压支架、采煤机和刮板输送机等配套设备的研制取得了重大突破,促进了大采高综采技术的进步。由于大采高综采具有资源回收率高、采出煤炭含矸率低、工作面生产时煤尘少、瓦斯涌出量小等方面的优点,使其成为在厚煤层开采技术方面迅速发展的新工艺。但是,许多专家和学者通过多年的现场观测和大量的理论研究发现,在类似地质条件下,大采高综采工艺随着工作面煤壁和支架高度的加大,支架-围岩系统的稳定性降低、事故率增加。如果再受到断层、裂隙、节理、褶曲、陷落柱等复杂地质条件及煤质松软且煤层本身为节理、裂隙发育的软弱煤层等因素的影响时,极有可能会使得大采高综采工作面支架-围岩系统的稳定性更差、事故率更高,给煤矿的安全生产带来严重的隐患。深入、系统地研究软煤层大采高综采采场围岩控制理论及技术,不仅能为类似煤层煤矿的设计、开采、安全生产的管理和决策提供科学依据,同时还能够丰富和发展矿山压力及岩层控制理论,所以,此课题的研究具有重要的理论意义和工程实际意义。作为软煤层大采高综采采场围岩控制理论及技术研究的初始阶段,论文以晋城煤业集团赵庄煤矿二叠系下统山西组3号煤层及其顶底板为主要研究对象,采用现场实测、理论分析、数值模拟计算和工业性试验等方法,对软煤层大采高综采工作面矿山压力显现规律、顶板岩层结构及运动破坏规律、煤壁片帮机理及防治技术、底板损伤破坏、支架-围岩关系以及开采技术保障体系等六个方面做了探索性研究。主要研究成果如下:(1)通过现场实测的方法,揭示了软煤层大采高综采工作面矿山压力显现的基本特征和规律。(2)以“砌体梁”理论为基础,较系统地研究了软煤层大采高综采采场上覆岩层的结构形态、运动破坏规律等方面的内容。构建了软煤层大采高综采采场基本顶岩层的平衡结构模型,分析了基本顶岩层受力和变形的影响因素;提出了在软煤层大采高条件下,基本顶“砌体梁”结构也具有回转变形失稳和滑落失稳两种失稳的可能性,并给出了这两种失稳产生的条件;利用弹性力学变分问题方法对直接顶力学模型进行了求解,得出了直接顶岩层下沉量与基本顶回转角、弹性模量以及液压支架工作阻力的关系。(3)通过对赵庄煤矿3305软煤层大采高综采工作面前方煤体塑性区宽度的数值模拟和理论计算,得出了软煤层大采高综采工作面煤壁的塑性区宽度;分析了软煤层大采高综采工作面煤壁片帮的主要影响因素,提出了防治煤壁片帮的措施。(4)运用弹塑性理论计算出了赵庄煤矿3305软煤层大采高综采工作面前方底板岩层和采空区范围内底板岩层的支承压力;建立了软煤层大采高综采采场底板岩层应力的计算模型,应用Westergard应力函数,对该模型进行了分析计算,得出了在三个边界条件下的采场围岩应力计算公式;根据Coulomb-Mohr准则,通过对平面应力状态下软煤层大采高综采采场边缘破坏区的分析,得出了平面应力状态下和平面应变状态下软煤层大采高综采采场边缘底板岩层最大破坏深度的计算公式;利用修正后的采场底板岩体极限载荷计算公式和滑移线场理论,建立了软煤层大采高综采采场支承压力所形成的底板屈服破坏深度的计算模型,通过对该模型的分析计算,得出了煤层底板岩层的最大破坏深度、最大破坏深度距离工作面端部的水平距离、采空区内底板岩层沿水平面方向最大破坏长度的计算公式。(5)通过对软煤层大采高综采工作面液压支架工作阻力与顶板下沉量关系的研究,得出了在基本顶给定变形的条件下,软煤层大采高液压支架所承担给定变形的比例小于普通采高液压支架,并给出了液压支架初撑力、工作阻力的确定原则。构建了端面顶板漏、冒的“块体”结构模型,揭示了软煤层大采高综采工作面端面顶板冒、漏的机理,并提出了防治措施。从液压支架的顶梁长度与直接顶的自承极限垮距长度之间的关系出发,对液压支架的顶梁长度、支柱位置与顶板的适应性进行了分析。构建了支架掩护梁的受力模型,利用散体介质力学理论,得出了液压支架掩护梁所受的水平推力和垂直压力的计算公式。(6)针对软煤层大采高综采工作面在复杂地质条件下,顶板破碎较为严重,容易产生漏、冒顶、漏风严重、上隅角瓦斯易超限等不安全隐患,结合赵庄煤矿3305软煤层大采高综采工作面的实际情况,采用现场实践的方法确定了开切眼和撤架通道顶板、两帮的支护加固技术、软煤层大采高综采工作面超前注射玛丽散N型材料加固煤壁技术、预防工作面煤壁片帮、冒顶的安全措施、工作面综合管理的安全措施、上隅角防治瓦斯超限措施。形成了一套较为完善的软煤层大采高综采辅助技术,为软煤层大采高综采工作面安全高产高效的实现提供了可靠的技术保障。总之,本文通过对软煤层大采高综采采场围岩控制理论及技术深入、系统的研究,解决了软煤层大采高综采中存在的实际问题,为今后类似煤层煤矿的设计、开采、安全生产的管理和决策提供了科学依据。更多还原

【Abstract】 China is rich in coal reserves, Thick coal seam reserves account for about 44% of the total reserves in China, Therefore, the thick seam mining technology to a great extent determines the level elevation of technology research and the exertion of economic efficiency of the entire coal industry of China. Over the last decade, The research and production of Large mining height hydraulic support, shearer and the scraper conveyor and other ancillary equipment have made a major breakthrough, contributed to great advances in technology of great mining height fully mechanized mining. As the great mining height fully mechanized mining has the advantage of high recovery rate, the low rate of coal gangue-containing, less coal dust production, small amount of gas emission, etc. , it rapidly developed into a new technology in the thick seam mining technology. However, through years of field observations and a lot of theoretical study many experts and scholars discover that, in similar geological conditions, With the wall of working face and the height of hydraulic support increase, the stability of hydraulic support - rock system will reduce and the accident rate will increase. If subject to impact of faults, fissures, joints, fold, collapse columns of complicated geological conditions and soft seam and the seam itself joints fractured, most likely that the stability of hydraulic support - rock system of the great mining height fully mechanized working face will be worse, the accident rate even higher, bringing serious risks to safety in production of the coal mine. In-depth and systematic study on the surrounding rock control theory and technology of soft seam great mining height fully mechanized stope, Not only provides a scientific basis for designing, mining, production safety management and decision-making of similar coal mine, at the same time is able to enrich and develop the mine pressure and strata control theory, Therefore, the study of this subject has important theoretical significance and practical significance.As the initial stage of study on the surrounding rock control theory and technology of soft seam great mining height fully mechanized stope, In this paper, the coal seam and the roof and floor of lowerpermian Shanxi formation seam 3 of Zhao zhuang coal mine in Jin cheng coal industry group were studied, Using methods such as on-site measurement, theoretical analysis, numerical simulation, and industrial test, etc., Exploratory study was done on six aspects, i. e., the regularity of mine pressure of soft seam great mining height fully mechanized stope, the structure and movement breakage regularity of roof rock, the rib fall mechanism and control techniques, the floor damage, the relationship of hydraulic support-surrounding rock and mining technology security system. The key results are as follows:(1)By on-site measurement method, the basic features and laws of the regularity of mine pressure of soft seam great mining height fully mechanized stope are revealed.(2)On the basis of the "lining beam" theory, aspects of morphology, movement breakage regularity of overlying strata of soft seam great mining height fully mechanized stope were systematically studied. A balanced structure model of main roof rock of soft seam great mining height fully mechanized stope was constructed; Two kinds of deformation instability and slip instability with the possibility of main roof "lining beam" structure,under soft seam great mining height conditions,were proposed. And these two conditions for instability occurs were also given; using the elasticity problem variational method, the mechanical model of immediate roof was solved, the relationship between the amount of immediate roof strata subsidence and therotation angle of main roof, elastic modulus and hydraulic support resistance was obtained.(3)By the numerical simulation and theoretical calculation of width of the plastic zone of coal front of the 3305 soft seam great mining height fully mechanized working face of Zhao zhuang coal mine, The mechanism of the rib fall of soft seam great mining height fully mechanized working face was obtained; the main factors of the rib fall of soft seam great mining height fully mechanized working face were analyzed, Control measures for the rib fall was proposed.(4)The set of degrees of support pressure rock bottom in front of working face and within goaf were calculated using elastic-plastic theory; rock stress calculation model for soft seam great mining height fully mechanized stope was established, Using Westergard stress function, by analyzing the model, the stope surrounding rock stress formula in the three boundary conditions was obtained; According to the Coulomb-Mohr criterion, Through the analysis of the edge of the destroyed areas of soft seam great mining height fully mechanized stope in the plane stress state and plane strain condition, the formula for calculating the depth of the greatest damage of soft seam great mining height fully mechanized stope was obtained; Using revised stope floor rock limit load calculation formula and slip-line field theory, the depth of yield damage calculation model of abutment pressure of soft seam great mining height fully mechanized stope was established, By calculation of the model, the formula of greatest damage depth of seam floor strata, the horizontal distance from the depth of the greatest damage to the face end and the length of the greatest damage of floor strata within goaf on horizontal direction were obtained.(5)Through the study of the relationship of hydraulic support working resistance and roof subsidence of soft seam great mining height fully mechanized working face, under the conditions of main roof given deformation, Hydraulic support of soft seam great mining height undertaken by a given percentage of given deformation was less than normal hydraulic support, principles were given to determine the setting load and working resistance of hydraulic support. The leakage "block" structure model of the end roof was constructed, Revealed the mechanism of the end roof leakage of soft seam great mining height fully mechanized working face, and proposed control measures. Proceeding from the relationship between the top beam length of hydraulic support and limit collapse gauge the length of immediate roof, carried out an analysis of the top beam length, pillar location of hydraulic support and roof applicability. The force model of shield-beam of hydraulic support was constructed, by granular media mechanics theory, the calculation formulas of the level of thrust and vertical pressure of shield-beam of hydraulic support were obtained.(6)In complex geological conditions, for the existence of roof strata broken severely, easy to form roof fall, severe leakage, upper corner gas easily overrun and the other hidden dangers of soft seam great mining height fully mechanized working face, With the actual situation of the 3305 soft seam great mining height fully mechanized working face of Zhao zhuang coal mine, On-site practical method was adopted to determine the support and reinforcement techniques of the roof and two side coal-walls of open-off cut and gateway, injection Malisan N material reinforcement technology advance soft seam great mining height fully mechanized working face, security measures to prevent the rib and roof fall, integrated management of working face safety measures, upper corner gas easily overrun measures. A set of perfect aid technology for soft seam great mining height fully mechanized was achieved, providing a reliable and efficient technical support for safe extraction in soft seam great mining height fully mechanized working face.In short, the thesis researches deeply and systematically into the theory and technology of surrounding rock control in soft seam great mining height fully mechanized stope, solves the practical problems existing in soft seam great mining height fully mechanized and has reference value to the future similar coal mine design, mining, product safety.更多还原