【作者】 何涛；

【导师】 邓广哲；

【作者基本信息】 西安科技大学 ， 采矿工程， 2009， 硕士

【摘要】 我国急倾斜煤层的储量丰富,分布范围广。开采急倾斜煤层的矿井产量占到全国的5%左右,但是生产矿井数量众多,占到全国矿井数的20%。主要分布我国西北部、东北以及东部沿海和西南地区的乌鲁木齐、窑街、淮南、开滦、徐州、长广、南桐、资兴、大通、华亭等矿区。其中,急倾斜特厚煤层水平分段综采放顶煤开采方法,已经在国内急倾斜厚煤层开采中得到广泛应用。急倾斜特厚煤层水平分段综采放顶煤开采过程中,顶煤主要依靠矿山压力、自重、上分段残留煤与矸石重量及支架反复支撑的共同作用下破坏、垮落。但遇到煤层硬度系数大于1以上的特厚煤层时,矿山压力较为缓和,仅靠上述作用不足以使硬度较大的顶煤破碎程度达到放出要求,顶煤的自然跨落困难,放顶煤回收率也将随之下降,严重影响到资源采出率的提高,生产中需要采取人工预先弱化顶煤的处理方式来解决。本文基于煤体致裂软化理论,通过分析坚硬顶煤水致裂过程煤体的软化规律,结合小红沟煤矿急倾斜特厚煤层B1、B2煤样的实验研究,以及影响顶煤软化性的主要因素模糊评价和分析,对煤层水致裂软化参数进行了系统研究。所做的主要工作及结果如下:(1)从力学角度分析了孔隙水作用下煤的破坏强度的变化,以及压力水作用下含裂纹煤体的断裂强度,阐述了水力致裂软化煤体的作用机理。(2)通过试验,分析了小红沟煤矿煤体的水理特性,以及煤体在不同含水率下的力学性质改变和破坏状态。(3)分析了影响顶煤水致裂的主要因素,运用模糊评价和模糊聚类方法对急倾斜大段高分段开采条件下顶煤软化主要影响因素进行了分析和模糊评价。(4)运用数值计算方法对采动过程围岩位移、应力状况进行了计算分析,确定了急倾斜大段高分段开采条件下顶煤软化水力致裂注水参数。更多还原

【Abstract】 Steep coal seam of our country is rich, and a lot of mines. The production in steep coal mines is about 5% but the amount of mines is about 20% in the country. The steeps coal mines are mainly located in Wulumuqi, Yaojie, Huainan, Kailuan, Xuzhou, Changguang, Nantong, Zixing, Datong, Huating etc... The sublevel caving mining of steep coal seam as an economic, safe, efficient mining method are widely used in steep thick coal seam mining. At the caving process, the top coal is broken and collapse forming loose irregular stack under the combined effect of the stress of the mining, the coal self weight, the weight of residual coal and waste rock at upper-paragraph and repeatedly support by the supporter. But sometimes, the seam coal strength is greater than 1, and less mining stress is not sufficient to enable the above-mentioned role to fracture top coal to meet the requirements to release, moreover, with the height of sublevel increases, the recovery rate will be lower, so we need to fracture top-coal in advance. In this paper, the author analyses the mechanism of hydraulic fracturing of coal and the role of hydraulic softening of coal, analyses the hydraulic property of the B1 & B2 coal in the Xiaohonggou mine by the experimental research and theoretical analysis, analyses the main factors of hydraulic fracturing and evaluates these factors using the fuzzy clustering analysis, and analyses the infusion parameters by the method of numerical simulation. The main job done and the results are as follows:(1) Analyses the change of coal failure strength under pore water from the mechanical point and the rupture strength of fractured coal under pressure water, revealed the mechanism of softening of hydraulic fracturing.(2) Through testing, analyses the coal mine hydraulic property and the change in mechanical properties under the action of water, as well as the different failure state under the different moisture content of coal. (3) Analyses the main factors of hydraulic fracturing of sublevel caving mining of steep coal seam and evaluates these factors using the fuzzy clustering analysis, and evaluates the softening character of B1 & B2 seam in the Xiaohonggou mine.(4) Calculates the rock displacement and stress conditions use the numerical methods, on this base, analyses the infusion parameters by the method of numerical simulation.更多还原