【作者】 吴刚；

【导师】 方新秋；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2015， 硕士

【摘要】 目前,我国许多矿区煤层开采属于近距离煤层群开采,高瓦斯、低透气性、煤与瓦斯突出的特点又严重影响矿井的安全生产与经济效益的提高。实践证明,开釆保护层并结合被保护层的卸压增透效应进行合理的瓦斯抽采是最有效区域性瓦斯防治技术。针对沙曲矿低透气性、高瓦斯、近距离煤层群、煤与瓦斯突出等复杂条件下的上保护层卸压开采问题,采用理论分析、数值模拟、现场试验等方法,研究分析了上保护层开采过程中顶底板煤岩层移动变形破坏规律、应力分布特点、裂隙发育演化规律、被保护层透气性演化规律、煤层群卸压瓦斯运移储集规律、保护层工作面的瓦斯涌出以及采动裂隙场与卸压瓦斯运移之间的相互作用关系。采用理论分析和数值模拟确定了上保护层开采的底板破坏深度与卸压保护范围。对上保护层开采过程中覆岩垮落动态发展过程进行了数值模拟,得出了顶底板移动破坏规律以及被保护层煤体应力和变形分布特征,并模拟分析了不同因素对卸压效果的影响。构建了上保护层卸压开采煤与瓦斯共采技术体系,分析了抽采钻孔布置方式对抽采效果的影响,并对瓦斯抽采技术进行了优化,对上保护层卸压开采现场应用效果进行了评估。现场工业性试验结果表明,上保护层工作面平均日产量1077t,平均瓦斯抽采率为55.77%,被保护层的平均瓦斯抽采率为78.3%,瓦斯抽采效果显著。研究结果表明,沙曲矿2号煤层作为上保护层开采对下部被保护煤层卸压效果显著,达到了防治煤层群煤与瓦斯突出的目的,实现了煤与瓦斯安全高效共采的目标。更多还原

【Abstract】 Many coalfields in China are faced with close distance coal seams in present days, featured by high-gas, low permeability and potential risk of coal and gas outburst which increase the difficult of mining safety and decrease the profit of the mine. Demonstrated by practices, the combination of mining protective layer and the antireflection effect through pressure relief of the protected layer and rational gas extraction activities is the most effective regional control technology.In allusion to the upper protective layer mining problem under the complex conditions of low permeability, high-gas and potential risk of coal and gas outburst of close coal seams in Shaqu coalmine, by using the method of theoretical analysis, numerical simulation and field test, we studied the mechanism of roof and floor strata movement and deformation, the distribution of stress, the fracture development, the permeability development of the protected layer, pressure relief gas migration and storage, gas emission in working face, the interaction between mining-induced fractures field and stress-relieved gas migration. The destroyed floor depth of upper protective layer mining and stress-relief protective range is determined by the method of theoretical analysis and numerical simulation. Numerical simulation on the dynamically process of overlying rock collapse lead to the mechanism of roof and floor strata movement and the stress and displacement distribution of protected layers during upper protective layer mining, and the impacts of different factors on pressure relief effect. We built up the technical system of simultaneous extraction of coal and gas as upper protective layer mining, analyzed the influence of distribution of gas drainage on the gas drainage effect and assessed the field application effect of upper protective layer mining. The result of field test shows that the average output of upper layer mining is 1077t/d, the average gas extraction rate is 55.77%, which is 78.3% in protected layers.The result of research indicates that No.2 coal layer of Shaqu coalmine being mined as protective layer has an enormous effect on the pressure relief of downward layer, which achieved the goal of prevention of coal and gas outburst and safe and efficient coal and gas simultaneous extraction.更多还原