【作者】 温克珩；

【导师】 柴敬；

【作者基本信息】 西安科技大学 ， 矿业工程， 2009， 博士

【摘要】 煤炭是我国主要能源,随着煤炭的连续开采,浅、表部煤炭资源越来越少,目前已转向深部煤层的开采。为了提高综放开采煤炭的回收率,国内学者提出了采空区一侧回采巷道采用留窄煤柱沿空掘巷的方法。综放面窄煤柱由于受到动压的影响,其破坏规律异常复杂,这导致煤巷锚杆支护技术遇到极大的挑战。开展该项研究对降低煤炭开采损失、减少巷道支护和维护成本、提高经济效益、保证矿井安全生产等具有重要意义。本论文以甘肃靖远煤业集团公司魏家地煤矿为依托,采用现场试验、理论分析、数值模拟的综合方法对高应力煤柱的物理力学特性、破坏模式、受动压影响的煤体损伤及破坏规律、煤柱最优留设尺寸、支护方案优化设计进行系统的研究,目的是对综放面合理留设煤柱尺寸及其支护设计提供理论依据。通过对综放面沿空掘巷上覆岩体垮落运动规律的研究,基本顶初次来压形成“O-X”破断,基于综放沿空掘巷上覆岩体结构的关键块的观点,对该结构中的关键块的特征参数进行了研究。建立合理的分析模型,分析了综放沿空掘巷上覆岩体结构在巷道掘进前、掘进时、掘进后的稳定性,揭示了该类巷道围岩大变形受上覆岩体结构稳定性影响的规律。通过综合分析厚煤层综放沿空掘巷窄煤柱的力学状态和破坏机理,得出了综放面沿空煤体边缘依次为卸载松散区、塑性强化区、弹性变形区、原始应力区,并得出了沿空煤体边缘应力极限平衡区内任意一点的应力和屈服区宽度计算公式。窄煤柱处于边缘煤体支承压力降低区和沿空煤体屈服区,在沿空掘巷采动影响下,窄煤柱将受到破坏后再破坏,通过加强支护可以改善煤柱的破坏程度,保持煤柱稳定性,并探讨了窄煤柱宽度合理确定方法。通过对沿空掘巷围岩变形破坏规律及锚杆与围岩相互作用机理研究,认为:由于窄煤柱受上区段采空区侧向支承压力的影响,强度低,承载能力小,在本工作面的采动影响下窄煤柱发生变形破坏,将支承压力大部分转移到实体煤帮,使得实体煤帮的变形急剧增大,围岩难以控制,因此提高窄煤柱的稳定是控制沿空巷道围岩的关键。提出了沿空掘巷窄煤柱巷道围岩控制的基本原理。采用FLAC^3D对魏家地煤矿X1-107综放工作面两道进行了数值模拟研究,掌握极软、特厚孤岛综放工作面锚杆、锚索联合支护巷道的矿压显现规律和锚杆、锚索支护效果,确定合理的煤柱宽度、支护形式和支护参数。对魏家地煤矿X1-107工作面风巷和机巷围岩稳定状况、锚杆工况等进行了全面的监测,工程实践表明窄煤柱是沿空掘巷稳定的关键,加强窄煤柱的支护,既提高了窄煤柱承载能力,减少三角块回转下沉,控制顶煤的下沉量,又维护了窄煤柱自身稳定,减少两帮相对移近量,保证巷道围岩整体稳定。X1-107工作面风巷、机巷顶板及两帮采用高强度螺纹钢锚杆支护、并对顶板采用小孔径预应力锚索加强支护,有效地保持了围岩稳定。更多还原

【Abstract】 Coal is the main energy resource of our country. With the continuous mining of coal, the coal resources of the shallow area become less and less, and now the focus is transferred to deep coal seam mining. In order to promote the coal recovery of fully mechanized caving, many domestic researchers proposed a new method which is driving roadway along next goaf with narrow coal pillar. The deformation of narrow coal pillar is complex because of the influence of dynamic pressure, which brings great challenge for the bolt support technology of coal roadway. The research conducted in this paper has very important significance for reducing the loss of coal and the costs of supporting and maintaining of roadway, promoting the economic benefit and ensuring the safe production.In this paper, supported by Weijiadi Coal Mine of Jingyuan Coal Industry Group of Gansu Province, with laboratory test, field test, theoretical analysis and numerical simulation, the mechanical characteristics, deformation, damification of coal under dynamic pressure, optimum coal pillar size and the supporting method are studied systemicly, which is aimed at providing theoretical base for optimum coal pillar size of coal pillar and its supporting designing.With the research of caving behavior of the overburden on the roadway along next goaf of fully mechanized caving mining face, the main roof will break liake "O-X". Based on the theory of key block, the characteristical parameters of the key block are studied. A logical analysis model is built, the stability of the overburden on the roadway along next goaf of fully mechanized caving mining face before drilling, drilling and after drilling is analyzed.With the synthesized analyse of the mechanical state and deformation of the coal pillar of the roadway along next goaf of fully mechanized caving mining face, the edge of the coal along next goaf are divided by unloading relax area, plastic strengthening area, elastic deformation area and in situ stress area, and the formulation of the stress and the width of yielding zone of the coal pillar is deduced. The narrow pillar is located at the supporting stress decreased area of the maginal coal mass and the yielding area of the coal mass along next goaf. With the influence of the driving of the roadway along next goaf, the narrow pillar will deform again. The deformation of the coal pillar can be decreased by strengthening support, and the stability of the coal pillar can be maintained.With the study of the deformation of the surrounding rock of the roadway driving along next goaf and the principle of the interaction of bolt and surrounding rock, it is discovered that, the narrow coal pillar has low strength and small bearing capacity because of the influence of the side abutment pressure of the upper curtate. With the mining influence of current mining face, the narrow pillar will deformed and the supporting pressure will be transferred to the coal mass side, and the deformation of the coal mass side increases and it is very hard to control. So, it is very important to improve the stability of the narrow coal pillar. The basic principle of the control of narrow coal pillar is proposed.FLAC3D is used in this chapter to do the numerical study of the roadway of X1-107 mining face at Weijiadi Coal Mine. The ground pressure and the bolt support effect of the roadway of the mining face are obtained, and the width of coal pillar, the support kind and support parameter are determined.The monitoring of the stability and the bolt condition of air roadway and conveyor roadway of X1-107 mining face at Weijiadi Coal Mine is conducted. The engineering practice shows that narrow coal pillar is the key to the stability of roadway alone next goaf. The strengthening of the narrow coal pillar support can improve the bearing capability of cal pillar, decrease the rotary settlement of the triangular block, control the settlement of the roof coal, maintain the stability of coal pillar itself, decrease the relative convergence of the sides of roadway and ensure the whole stability of the surrounding rock of the roadway. The air roadway and conveyor roadway of X1-107 mining face are supported by high strength thread steel bolt and enhanced with small diameter prestressed anchor cable on the roof, which has maintain the stability of the surrounding rock effectively.更多还原