【作者】 汪东生；

【导师】 杨胜强；

【作者基本信息】 中国矿业大学 ， 安全技术及工程， 2009， 博士

【摘要】 容光矿井煤层存在瓦斯含量高、煤层层数多且煤层间距小、煤层为煤与瓦斯突出煤层、煤层渗透性低、煤层透气性差、抽采有效半径小、抽采时间短、构造复杂、孔被水封导致钻孔难以发挥作用等特点,为此,在容光矿井开展了近距离煤层群保护层开采瓦斯立体抽采防突理论与实验研究,建立了近距离煤层群保护层开采瓦斯立体抽采防突理论体系,推导出了近距离煤层群保护层开采瓦斯立体抽采防突认证方程和适合容光煤矿瓦斯立体抽采防突认证方程。完成了瓦斯立体抽采防突和认证实验研究,通过试验得出了本煤层回采工作面平行抽采钻孔抽采、顶板高位走向钻孔抽采、回采工作面采空区“T”型网管抽采、底板穿层钻孔抽采等合理的布置方式,在立体上采取综合防突措施,由“单一平面抽采”变为“立体综合抽采”,克服单一防突措施的不足,从根本上消除突出危险。开发研制了PE矿用塑料导向滑轮管道瓦斯抽采护孔技术,提高了钻场瓦斯抽采率。采用UDEC模拟了近距离上保护层开采过程中覆岩垮落动态发展过程,得出了底板和覆岩破裂移动规律,及随保护层工作面推进,被保护层煤体应力和变形分布特征,进而分析了它对合理布置卸压抽采钻孔和消除被保护层突出危险性的作用。系统的将近距离煤层卸压瓦斯储集和运移规律与采动覆岩移动、裂隙演化过程有机的结合起来,科学的、完整的将瓦斯灾害治理工程与采场卸压瓦斯流动规律、瓦斯富集区统一考虑,环型裂隙圈是动态的,瓦斯运输和储集也是动态变化的。对垮落带破碎煤岩的渗透率进行量化研究,推导出了回采期间采空区垮落带的渗透率半理论化的表达式,并将其应用于瓦斯立体抽采系统中。采用了FLUENT软件,模拟了近距离煤层瓦斯立体抽采防突过程,发现了近距离保护层开采过程中的煤岩体裂隙动态时空演化风流流场分布规律及瓦斯分布规律;顶板高位走向钻孔配合“T”型网管抽采情况下,增加了工作面的瓦斯抽排量,减少了工作面上隅角的瓦斯涌出;抽采钻孔周围煤体中瓦斯压力分布,从钻孔中心向外呈增大扩散,钻孔周围煤体中瓦斯流动速度场分布,从钻孔中心向外呈减小扩散。建立了一套回采工作面瓦斯立体抽采防突综合治理措施和防突管理体系。通过C₅煤层本煤层抽采瓦斯含量降到5.83m³/t,瓦斯压力降到0.28Mpa;通过底板穿层钻孔和高位走向钻孔抽采被保护层卸压瓦斯,C₆、C₈煤层瓦斯含量降为3.04m³/t、3.22m³/t,C₆、C₈煤层瓦斯压力降为0.35MPa、0.42Mpa,C₆、C₈煤层透气性系数增加250和284倍,煤层各项测定指标降到了该煤层突出危险临界值以下,采煤工作面回风流瓦斯浓度由1.5%以上下降到0.30%以下,回风流绝对瓦斯涌出量由24.33m³/min下降到4.50m³/min以下。在整个开采过程中,没有出现煤与瓦斯突出事故,没有出现瓦斯超限作业,日安全出煤2000t,年产值达到2.4亿元,瓦斯立体抽采防突抽排技术效果是明显的,取得了巨大的经济效益和社会效益,有广泛的推广使用价值。更多还原

【Abstract】 The gas stereo drainage theoretical system for outburst prevention of mining of closed distance coal seam group with Protection Layer Mining was set up, based on The coal seams characteristics of Rongguang Coal Mine, such as: high gas content, many coal seams, short distance between seams, coal and gas outburst, low permeability of coal seam, small drainage radius, short time of drainage, complex structure and bad gas drainage influenced by water. The authentication equations of stereo gas drainage for outburst prevention under closed distance seam group with protection layer mining and stereo gas drainage for outburst prevention in the Rongguang Coal Mine were derived. Authentication experiment of stereo outburst prevention was established, measures for stereo outburst prevention were presented as follow: drainage in current seam with horizontal borehole, drainage with high location strike drilling hole, goaf drainage with“T”type tube, drainage with drilling holes from floor. The drainage method was changed from drainage in a single horizontal plane to multi-direction that could solve the deficiency of old method and outburst problems. The hole protection technology with PE mine plastic guiding pulley pipeline during gas drainage was developed, improving the gas drainage rate in a drilling field. The dynamic development of overlying strata collapse with short distance upper protective layers method was simulated by UDEC, the rules of strata and floor movement, coal bed stress and strain of protected seam were obtained. The significance of it for drainage drilling holes optimization. Gas reservoir of short distance coal seams, movement of mining strata and fracture evolvement were analyzed together. Quantitative research on permeability of crushing rock mass in falling zone was carried out, and then the semi-theoretical permeability equations of falling zone were described, and applied to stereo gas drainage. The every process of gas stereo outburst prevention and drainage was simulated with FLUENT. The rules of gas flow and methane contribution with short distance upper protective layers method were found; Drainage with high location strike drilling hole could enhance methane drainage and reduce methane emission of upper corner; The methane pressure of drilling holes becomes larger from the center to outer circle, and the methane flow velocity gets smaller.It was set up that the safety management measures of gas stereo drainage and outburst prevention for short distance coal seams. The tests with gas stereo drainage and outburst prevention method indicate that the gas content and pressure of C5 coal seam were reduced to 5.83m³/t and 0.28Mpa, and the gas content and pressure of C₆, C₈ to 3.04m³/t,3.22m³/t and 0.35MPa, 0.42Mpa respectively, as the same time, the increment of permeability of C₆, C₈ achieved 250times and 284 times. The parameters of outburst prevention were below the critical value. The methane concentration of return was changed from 1.5% to 0.3% and the methane flow rate of return became below 4.50m³/min to below 24.33m³/min. There were no coal and gas outburst accident in the whole mining process and daily yield was 2000t, annual output value exceeding 0.24 billion. The effects of gas stereo drainage and outburst prevention was obvious, the method was proved that it was worth for extension.更多还原