倾斜煤层综放开采覆岩裂隙演化规律及应用研究

发布时间：2018-03-24 00:25

本文选题：裂隙演化　切入点：相似模拟　出处：《西安科技大学》2017年硕士论文

【摘要】：采用高位钻场抽采治理采空区瓦斯时,将钻孔布置在覆岩垮落的裂隙带内时抽采效果最佳。为了分析覆岩裂隙的演化规律,本文以新疆某矿井为地质原型,结合覆岩裂隙演化和瓦斯抽采等相关理论,采用物理相似模拟实验和数值模拟实验对裂隙演化规律进行分析,并将实验结果和现场测试结果对比分析,进一步研究了覆岩裂隙时空演化规律在高位钻孔抽采瓦斯中的应用方法。以现有覆岩裂隙演化规律为基础,结合矿井地质背景,设计并开展物理相似模拟实验,模拟了煤层在开采过程中裂隙在走向和倾向上的演化规律。由实验结果分析可知每次周期来压的裂隙发育特征以及岩层的垮落规律,覆岩“三带”的高度中冒落带高度为26m,裂隙带高度为75.8m;引入分形理论,研究了覆岩裂隙网络的分形特征,得出分形维数与开采宽度、支承压力峰值的关系,定量研究了走向倾向不同区域的裂隙演化与分布特征,并整体拟合出裂隙发育的椭抛带区域;应用fluent数值模拟软件,结合相似模拟及分形理论所得出的裂隙分布规律,模拟高位钻孔抽采前后采空区瓦斯浓度变化情况,以及抽采前后不同层位瓦斯浓度对比,结果表明,高位钻孔抽采效果显著,特别是回风一侧瓦斯浓度大幅降低。基于高位钻孔抽采瓦斯机理以及覆岩裂隙高瓦斯浓度区域的确定,以新疆某矿区现场实际情况及高位钻孔抽采数据和效果为依据,分析不同位置处抽采瓦斯体积分数的变化规律,得出将高位钻孔在采动裂隙椭抛带中抽采卸压瓦斯是合理的,可以保证综放工作面瓦斯浓度不超限。
[Abstract]:In order to analyze the evolution law of overburden fractures, this paper takes a coal mine in Xinjiang as the geological prototype, when the borehole is arranged in the crack zone of overburden rock collapse, the extraction effect is the best when the gas in goaf area is controlled by high drilling ground. Combined with the related theories of overburden fracture evolution and gas drainage, the law of fracture evolution is analyzed by physical similarity simulation experiment and numerical simulation experiment, and the experimental results are compared with the field test results. The application method of space-time evolution law of overburden fracture in gas extraction by high hole drilling is further studied. Based on the existing evolution law of overburden fissure and combined with mine geological background, the physical similarity simulation experiment is designed and carried out. This paper simulates the evolution law of fracture strike and tendency in coal seam during mining. The analysis of experimental results shows the fracture development characteristics of each cycle pressure and the law of rock formation collapse. The height of falling zone is 26m and the height of fracture zone is 75.8m.The fractal characteristic of overburden fracture network is studied by introducing fractal theory, and the relationship between fractal dimension and mining width and peak value of supporting pressure is obtained. The characteristics of fracture evolution and distribution in different areas of strike tendency are quantitatively studied, and the elliptical zone of fracture development is fitted as a whole, and the distribution law of fracture is obtained by using fluent numerical simulation software, combining with similarity simulation and fractal theory. The gas concentration changes in the goaf before and after the extraction of the high hole and the comparison of the gas concentration in different strata before and after the extraction are simulated. The results show that the extraction effect of the high hole is remarkable. In particular, the gas concentration on the backwind side is greatly reduced. Based on the gas extraction mechanism of the high hole and the determination of the high gas concentration area in the overburden fissure, the actual situation of a mining area in Xinjiang and the data and effect of the high hole drainage are taken as the basis. By analyzing the variation law of gas volume fraction at different positions, it is concluded that it is reasonable to extract and discharge pressure gas in the elliptical parabolic zone of mining fissure, which can ensure that the concentration of gas in fully mechanized caving face is not over the limit.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD712

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