隧道瓦斯钻孔排放有效半径影响因素分析

Analysis of Influence Factors on Effective Radius of Tunnel Gas Drilling Emission

以林(歹)织(金)铁路坪子上高瓦斯隧道为工程背景,基于COMSOL的流固耦合数值模拟,分析了隧道瓦斯排放时间和钻孔深度对钻孔排放有效半径的影响,根据瓦斯钻孔排放有效半径确定合理的钻孔间距。研究发现:当钻孔半径和钻孔深度一定时,钻孔排放有效半径随瓦斯排放时间的增大明显增大,影响区域也明显增大;当钻孔半径和瓦斯排放时间一定时,钻孔排放有效半径随着钻孔深度的增大而增大,影响区域也增大,但增加不明显。为了防止瓦斯抽放空白带的出现,给出了瓦斯排放合理钻孔间距的计算公式。

Pingzishang high-gas tunnel on Lindai-Zhijin railway is the engineering background in this paper.Based on the numerical simulation of C O M SO L fluid-solid coupling,the effect of the gas drainage time and the drilling depth on the effective radius of drilling emission was analyzed,and the reasonable hole spacing was determined by the effective radius of drilling emission.Results show that the effective radius of drilling emission and the corresponding influence area increases obviously with the increase of the gas drainage time when the drilling radius and the drilling depth are constant,but not significantly with the increase of the drilling depth when the drilling radius and the gas drainage time are constant.Finally,this paper proposed an equation used for the reasonable hole spacing of gas drainage,in order to prevent the emergence of blank zone of gas emission.