高强内支撑护孔管提高瓦斯抽采钻孔稳定性技术及应用研究

发布时间：2018-03-26 00:32

本文选题：钻孔　切入点：瓦斯抽采　出处：《中国矿业大学》2017年硕士论文

【摘要】：我国松软高瓦斯煤层分布较广,井下钻孔抽采瓦斯是目前预防瓦斯灾害的主要措施,由于松软煤层煤体硬度低,抽采钻孔在成孔与抽采期间容易坍塌、变形,瓦斯流动通道被阻塞,使瓦斯抽采效率降低。本文通过理论分析、实验室测定、数值计算和工程试验的方法,利用高强内支撑护孔管对提高瓦斯抽采钻孔稳定性技术进行研究。从影响钻孔稳定性因素出发,探讨了钻孔周围轴向与径向“三带”的划分、研究了钻孔在支护作用下应力与位移计算式,并分析了护孔管在钻孔内的主要受力。从护孔筛管的选型入手,分析了护孔筛管在钻孔内受力特性,对比了护孔筛管材料的基本力学性能:(1)PPR管抗压缩变形能力更强,但抗拉伸与扭转剪切能力较差;PE管在基本力学实验中表现适中;PVC管则相对较差。(2)新型内支撑管径向抗压能力比普通管提升了3倍多。利用FLAC3D数值模拟软件,对钻孔塌孔特性进行研究,在支护作用下钻孔顶端垂直位移减小、围岩垂直应力分布与围岩塑性区范围变小,且在高强内支撑护孔管支护下效果更加显著。通过不同支护方式及不同类型筛管支护现场工程试验,表明:(1)护孔筛管的筛孔直径8mm、密度6个/m或8个/m较好。(2)内支撑筛管支护、普通筛管支护瓦斯抽采纯量与裸孔对比分别提高1.05倍、0.58倍,且内支撑筛管支护抽采达标时间大幅度下降。
[Abstract]:Because of the wide distribution of soft and high gas seams in China, gas extraction by borehole is the main measure to prevent gas disaster at present. Because of the low hardness of coal body in soft coal seam, it is easy to collapse and deform during drilling and drawing. The gas flow passage is blocked, which reduces the efficiency of gas extraction. The method of theoretical analysis, laboratory measurement, numerical calculation and engineering test is used in this paper. The technique of improving the borehole stability of gas drainage is studied by using the high strength inner bracing pipe. Based on the factors affecting the borehole stability, the division of the axial and radial "three zones" around the borehole is discussed. The formula of stress and displacement of borehole under the action of supporting is studied, and the main force of hole guard pipe in borehole is analyzed. Starting with the selection of sieve pipe, the stress characteristics of the pipe in borehole are analyzed. Compared with the basic mechanical properties of the sieve pipe material for hole protection, the ratio 1 / 1 PPR pipe has stronger compressive deformation resistance. But the tensile and torsional shear strength of PE pipe is relatively poor in basic mechanical experiment. The characteristics of borehole collapse are studied. The vertical displacement of the top of the borehole decreases, the vertical stress distribution of surrounding rock and the range of plastic zone of surrounding rock become smaller under the action of support. Through the field engineering test of different support ways and different types of sieve pipe support, it is shown that the diameter of sieve hole is 8 mm, the density of 6 / m or 8 / m is better than that of inner support sieve pipe support. Compared with bare hole, the scalar amount of gas extraction in common sieve pipe support is increased by 1.05 times and 0.58 times respectively, and the time of drawing standard of inner support sieve pipe support is greatly reduced.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD712.6

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