大同矿区双系煤层开采覆岩大范围运动规律及结构特征研究

发布时间：2018-07-16 20:34

【摘要】：大同矿区双系煤层开采条件下坚硬顶板大面积悬露突然垮断时,易造成工作面矿压显现加剧,来压强度大,严重影响工作面正常生产,威胁井下人员的生命安全,因此,研究大同矿区双系煤层开采顶板大范围运动规律及顶板结构失稳条件,对于坚硬顶板条件下工作面矿压显现规律及顶板控制具有重要的现实意义和理论价值。采用物理相似模拟及计算机数值计算的方法,研究了双系煤层开采过程中覆岩破断结构特征及应力场、位移场的分布规律。研究表明,侏罗系遗留煤柱影响深度约63m,水平影响区域范围为35~40m,最大应力集中系数为3.14,石炭系综放煤层下位坚硬直接顶呈不同步垮落失稳,上位关键层初次断裂步距较大,且主关键层的失稳导致双系煤层采空区贯通,覆岩顶板结构渐次向上扩展,结构形态为“下位组合悬臂梁结构-上位多层砌体梁结构”,该结构作为石炭系煤层覆岩顶板中的骨架,对工作面矿压显现起到决定性作用。通过理论分析,对顶板结构的渐次扩展范围进行判定,分析不同结构形式下其失稳的力学条件及失稳方式,并结合同忻煤矿8101工作面实际生产条件,对现场矿压显现规律进行实测,结果显示,工作面下位坚硬顶板初次来压步距约106m左右,上位亚关键层初次来压步距为133.5m,工作面周期来压步距约17m,来压强度呈一强一弱周期性交替显现,强弱周期性交替来压与下位坚硬直接顶及上位亚关键层的周期性破断一致,该矿压显现规律与“渐次扩展结构”失稳运动的理论分析相吻合。研究结果对大同矿区石炭系煤层开采矿压显现规律及支架选型具有指导意义及理论价值。
[Abstract]:When the hard roof overhanging suddenly collapses under the condition of double-system coal seam mining in Datong mining area, it is easy to cause the coal pressure of the working face to appear worse and the pressure intensity is large, which will seriously affect the normal production of the working face and threaten the life and safety of the downhole personnel. It is of great practical significance and theoretical value to study the large range movement law of roof and the unstable condition of roof structure in Datong coal mining area, which is of great practical significance and theoretical value for the rock pressure behavior law and roof control of working face under the condition of hard roof. By using the method of physical similarity simulation and computer numerical calculation, the characteristics of overburden fracture structure and the distribution of stress field and displacement field in the mining process of double system coal seam are studied. The results show that the influence depth of Jurassic coal pillar is about 63 m, the horizontal influence area is 35 ~ 40 m, the maximum stress concentration factor is 3.14, the hard direct roof of coal seam in the coal seam of Carboniferous fully mechanized caving seam is unstable and the first fault step of the upper key layer is large, the influence depth of the coal pillar is about 63 m, and the maximum stress concentration factor is 3.14 m. And the instability of the main key layer leads to the goaf of the double system coal seam through, the roof structure of overlying rock expands gradually up, and the structure form is "the structure of the lower position combination cantilever beam structure-the upper multistory masonry beam structure". As the skeleton of overburden roof of Carboniferous coal seam, the structure plays a decisive role in the coal face pressure. Through theoretical analysis, the gradual extension range of roof structure is determined, the mechanical conditions and instability modes of the roof structure under different structural forms are analyzed, and the actual production conditions of 8101 face in Tongxin Coal Mine are combined. The measured results show that the first step distance of the hard roof in the working face is about 106m. The first step distance of upper subcritical layer is 133.5 m, and the interval of working face periodic pressure is about 17 m. The intensity of incoming pressure appears as a strong and weak periodic alternately, and the strong and weak periodic alternating pressure is consistent with the periodic breaking of the lower hard direct roof and the upper sub-key layer. The behavior of the rock pressure is consistent with the theoretical analysis of the instability of the "gradual spread structure". The results of the study are of guiding significance and theoretical value to the mining pressure behavior law and support selection of Carboniferous coal seam in Datong mining area.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD325

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