【作者】 于洪；

【导师】 陆庭侃；

【作者基本信息】 河南理工大学 ， 采矿工程， 2009， 硕士

【摘要】 瓦斯灾害是威胁煤矿安全生产的自然灾害之一,预防瓦斯灾害对煤矿安全生产具有十分重要的意义。虽然国内外专家学者在煤矿瓦斯抽放方面进行了大量的研究工作,但抽放效率低。卸压增透是提高高瓦斯低透气性煤层瓦斯抽放率的重要途径,其关键技术的研究对我国煤矿瓦斯灾害防治有着深远而重要的意义。本文主要针对如何解决高瓦斯低透气性煤层的瓦斯抽放困难的问题,提出了高压水射流割缝强化瓦斯抽放技术。该技术是通过降低煤层原岩应力,改变煤层物理力学性质,以达到提高煤层透气性的目的。首先,研究以煤层瓦斯运移规律、高压水射流割缝卸压增透机理为基础,借助FLAC5.0软件对高压水射流割缝后煤层卸压效应以及对影响卸压效应的割缝参数进行模拟与分析,割缝后缝槽周围煤体出现大面积的卸压区域,并产生不同程度的位移及破坏;另一方面,以水射流理论及相关学科理论为基础,运用FLUENT软件对喷嘴结构进行设计,通过正交试验优化了喷嘴几何结构参数,对系统主要设备进行改进和选型,设计出了高压水射流割缝系统,并对该系统进行了性能可靠性与稳定性测试;最后,结合数值模拟结果和汝箕沟煤矿32211工作面的现场情况,确定高压水射流强化瓦斯抽放的钻孔布置方案以及割缝参数。现场工业性试验研究表明:高压水射流割缝技术可以有效地释放地应力,增加钻孔周围煤体的裂隙,提高煤体的透气性,钻孔瓦斯抽放量平均提高了3.55倍,瓦斯浓度平均提高了37%。更多还原

【Abstract】 Gas accident is a major natural disaster which threatens the mine safety,the gas drainage has played a significant role in the mine safety. Although a great quality of research work in the gas drainage of coal mine have been carried out by the specialists at home and abroad, the efficiency of gas drainage was low. Stress release is a crucial means of improving gas drainage rate of coal seams with low permeability, and the research on key technology has exerted a profound influence on the gas disaster prevention of coal mine.This thesis focuses on solving the problem of gas drainage of coal seams with high gas content and low permeability,and proposes the technique of high pressure water jet slotting to intensify gas drainage, which changes the mechanical nature of coal seams in an attempt to improve the permeability of coal seams by means of reducing the original rock stress and increasing permeability of coal seams.Based on the theory of gas flow,and the mechanism of stress release by high-pressure water jet slotting,the effect of stress release after slotting and the slotting parameters have been simulated and analyzed with the help of FLAC5.0, the results indicate that stress release,displacement and fracture occurred about the slot after slotting.Moreover, on the basis of the water jet theory and other relevant factors, the structure of the nozzle has been designed using a commercial program FLUENT, and orthogonal experiment aiming at optimizing the parameters of the nozzle’s geometrical structure has been carried out, and the high pressure water jet slotting was created through improving the equipments of the whole system, then the tests of the reliability and stability of the system’s performance have been conducted. Finally, combining the above mentioned simulation results with the conditions of the work face, the borehole layout and slotting parameters have been determined. The field work has demonstrated that the technique can effectively release stress of coal seams so that it can improve the permeability of coal seams. Thus, the quantity of gas drainage and the gas concentration have been increased 3.55 times and 37% on the average respectively.更多还原