厚松散含水层下薄基岩采场水—岩耦合致灾机理研究

发布时间：2018-03-24 00:26

本文选题：厚松散层　切入点：承压含水层　出处：《安徽理工大学》2017年硕士论文

【摘要】：华东矿区普遍存在新生界巨厚松散含水覆盖层,且煤层上方基岩厚度薄、风化严重,在临近厚松散含水层采煤过程中,工作面来压期间顶板压力异常释放,发生多起致灾事故。本文以淮南潘谢矿区顾北矿1202(3)工作面为研究对象,基于矿区及工作面具体水文地质资料,结合理论分析、相似模拟、数值模拟和现场实践等研究方法,对厚松散含水层下薄基岩采场水-岩耦合致灾机理进行研究:(1)建立了厚松散含水层下薄基岩采场结构力学模型,得到了采场初次来压时液压支架需负担的覆岩总重量。采用相似模拟试验,对比分析了有、无承压含水层作用下采场覆岩移动、变形特征及采场支承压力演化规律。薄基岩采场在无承压水含水层作用下时,松散层自重及所施加载荷不是全部向下传递,覆岩前垮落角始终小于后垮落角。与之相比,承压含水层对于采场覆岩大范围运移起到推动作用,开采初期覆岩前垮落角小于后垮落角,随着开采范围扩大,覆岩前垮落角突然增大,采场覆岩表现为整体破断,破断形状沿煤壁呈切落状;覆岩载荷压实作用明显。(2)建立了流-固耦合和无耦合两种数值模型,在无耦合条件下,采场上方松散层内部最大主应力随煤层开挖而显著降低,前方最大主应力值增长缓慢。在流-固耦合条件下,采场受到承压水渗流场与采动应力场双重作用,煤岩体内部应力集中程度整体提高,采场前方最大主应力值近似呈线性增长。(3)厚松散含水层下薄基岩采场开采工程实践表明,初采期间两巷变形量及支架工作阻力随推进距离增加快速增长,顶板压力异常释放,导致液压支架受到瞬时冲击载荷作用,其无法支撑初次来压时失稳岩层重量。综上可知,在厚松散含水层下薄基岩单一主关键层条件下进行煤层开采工作时,承压含水层传递的载荷增加了采场围岩应力集中程度,整体破断的基岩块体重量及上覆载荷超过了液压支架的额定工作阻力,是工作面致灾的主要原因。研究成果对类似条件下的煤层开采具有一定的借鉴意义。
[Abstract]:In East China mining area, there is a very thick and loose water-bearing overburden in the Cenozoic, and the bedrock above the coal seam is thin and weathered seriously. During the mining process near the thick and loose aquifer, the roof pressure is abnormally released during the coming pressure period of the working face. In this paper, based on the hydrogeological data of mining area and working face, combined with theoretical analysis, similarity simulation, numerical simulation and field practice, this paper takes the 1202Y3 face of Gubei Coal Mine in Panxie Mining area of Huainan as the research object, combining with theoretical analysis, similarity simulation, numerical simulation and field practice, etc. This paper studies the mechanism of water-rock coupling disaster caused by thin bedrock stope under thick loose aquifer, and establishes the structural mechanics model of thin bedrock stope under thick loose aquifer. In this paper, the total overburden weight of the hydraulic support is obtained when the stope first comes under pressure. By using the similar simulation test, the overburden rock movement of the stope without the action of the confined aquifer is compared and analyzed. Deformation characteristics and evolution law of supporting pressure in stope. When thin bedrock stope under the action of no confined water aquifer, the weight of loose layer and the load applied are not all transmitted downward, and the front collapse angle of overburden is always lower than that of rear collapse angle. The confined aquifer promotes the large-scale migration of overburden rock in the stope. In the early stage of mining, the caving angle of overburden rock is smaller than that of later caving angle. With the expansion of mining scope, the caving angle of overburden rock suddenly increases, and the overburden rock appears as a whole broken down. Two numerical models of fluid-solid coupling and non-coupling are established. Under the condition of no coupling, the maximum principal stress in the loose layer above the stope decreases significantly with the coal seam excavation. Under the condition of fluid-solid coupling, the maximum principal stress increases slowly. Under the condition of fluid-solid coupling, the stress concentration degree in coal and rock mass is improved by the double action of confined water seepage field and mining stress field. The maximum principal stress in front of the stope is approximately linearly increased. The practice of thin bedrock mining under the thick and loose aquifer shows that the deformation of two roadways and the working resistance of the support increase rapidly with the increase of the propulsive distance during the initial mining period, and the roof pressure is abnormally released. As a result, the hydraulic support is subjected to the instantaneous impact load, which can not support the weight of the unstable rock during the initial pressure. In summary, it can be concluded that when the coal seam is mined under the condition of the single main key layer of thin bedrock under the thick and loose aquifer, The load transmitted by the confined aquifer increases the stress concentration of surrounding rock in the stope, and the mass of the whole broken bedrock block and the overburden load exceed the rated working resistance of the hydraulic support. The research results can be used for reference in coal seam mining under similar conditions.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD323;TD355.4

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