岩土力学 ›› 2019, Vol. 40 ›› Issue (7): 2517-2524.doi: 10.16285/j.rsm.2018.1543

• 基础理论与实验研究 • 上一篇    下一篇

负压对抽采钻孔孔周煤体瓦斯渗流特性的影响

张天军1,庞明坤1, 2,蒋兴科1,彭文清1,纪翔1   

  1. 1. 西安科技大学 理学院,陕西 西安 710054;2. 西安科技大学 安全科学与工程学院,陕西 西安 710054
  • 收稿日期:2018-08-27 出版日期:2019-07-11 发布日期:2019-07-06
  • 作者简介:张天军,男,1971年生,教授,博士生导师,主要从事矿山灾害力学方面的研究。
  • 基金资助:
    国家自然科学基金面上项目(No. 51774234,No. 51474172,No. 51734007);国家自然科学基金资助项目(No. 51604214)。

Influence of negative pressure on gas percolation characteristics of coal body in perforated drilling hole

ZHANG Tian-jun1, PANG Ming-kun1, 2, JIANG Xing-ke1, PENG Wen-qing1, JI Xiang1   

  1. 1. College of Science, Xi’an University of Science and Technology, Xi’an, Shaanxi 710054, China 2. College of Safety Science and Engineering, Xi’an University of Science and Technology, Xi’an, Shaanxi 710054, China
  • Received:2018-08-27 Online:2019-07-11 Published:2019-07-06
  • Supported by:
    This work was supported by the General Program of National Natural Science Foundation of China (51774234, 51474172, 51734007) and the National Natural Science Foundation of China (51604214).

摘要: 抽采负压是影响钻孔孔周煤体瓦斯渗流规律的重要因素之一,为了深入研究负压变化对煤体瓦斯渗流特性的影响,通过设计瓦斯渗流特性相似模拟试验平台对孔内瓦斯流动规律进行测定,并运用数值软件对孔周煤体内瓦斯渗流状态进行分析,结合上述结论对钻孔孔周煤体瓦斯渗流特性进行研究。结果表明:抽采负压提供孔周煤体瓦斯向钻孔内渗流的动力,负压值设定为25~35 kPa时,可保证雷诺数集中分布在10~20之间,其低速紊流状态有利于瓦斯高效抽采;随着抽采时间的增加,负压对瓦斯的引流作用逐渐减弱,瓦斯流量随时间呈现负指数衰减规律,煤体渗流速率饱和值处于7.41×10?6~1.30× 10?5 m/s之间;煤体内部黏滞阻力对瓦斯渗流存在抑制作用,随着抽采负压的增大,孔口负压上升趋势比孔周煤体内负压上升趋势更快,说明抽采负压变化对钻孔孔口负压的影响更为显著。

关键词: 负压, 抽采钻孔, 渗流特性, 瓦斯流动, 孔隙和裂隙

Abstract: Negative-pressure extraction is one of the most important factors affecting the seepage law of coal gas in the perforated hole. To study its influence, the gas flow in the hole was determined by designing a similar simulation test platform for gas seepage. Moreover, the numerical software was used to analyze the gas seepage in the coal around the hole. Combined with the above conclusions, the percolation characteristics of gas in the coal around the hole was studied. The results showed that the negative pressure was used to provide the power for gas seeping from the coal to the borehole. When the negative pressure was set in the range of 25~35 kPa, the Reynolds number was concentrated between 10 and 20. Thus, the low-speed turbulent flow is ensured, which was conducive to extracting the gas efficiently. With the increase of pumping time, the effect of negative pressure on the gas extraction gradually became weak, and the gas flow showed a negative exponential decay with time. The saturated value of coal seepage velocity was between 7.41×10?6 m/s and 1.30×10?5 m/s. The internal viscous resistance of the coal body inhibited the gas seepage. With increasing the negative-pressure extraction, the negative pressure of the borehole increased faster than that in the coal around the hole, which indicated the effect of the negative pressure on the borehole was more significant.

Key words: negative pressure, drilling, seepage characteristics, gas flow, pores and fissures

中图分类号: 

  • TD 315
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