煤层排放钻孔直径和排放时间对排放半径演化规律的影响研究

Study on Influence of Discharge Borehole Diameter and Discharge Time on Evolution Characteristics Law of Discharge Radius

煤层钻孔排放半径是局部防突的一个关键技术参数。为获得煤层钻孔排放半径与排放钻孔直径、排放时间之间的关系,以祁东煤矿为试验地点进行考察试验。采用现场试验与数值模拟的方法,分析在不同排放钻孔直径和不同排放时间下的煤层钻孔最大排放半径的演化规律。建立了一种排放半径计算方式;实测了祁东煤矿9煤层不同排放钻孔直径在排放不同时间后的最大排放半径;数值模拟获得水平方向上钻孔周围瓦斯压力呈现“U”形分布;排放时间相同情况下,煤层钻孔最大排放半径随着钻孔直径的增大而增大;排放时间和钻孔直径与排放半径分别满足不同的函数关系;获得了排放半径与排放钻孔直径与排放时间的耦合关系。

The emission radius of coal seam drilling is a key technical parameter for local outburst prevention,and the emission radius is directly related to the emission time and diameter of the emission drilling hole.In order to obtain the relationship between the emission radius of coal seam boreholes,the diameter of emission boreholes,and the emission time,an investigation experiment was conducted at Qidong coal mine.Using on-site testing and numerical simulation methods,analyze the law of the maximum emission radius of coal seam boreholes under different emission borehole diameters and emission times.The research results are as follows:a new calculation method for emission radius has been established;the maximum discharge radius of different discharge borehole diameters in the 9th coal seam of Qidong coal mine was measured after different discharge times;obtained through numerical simulation:the gas pressure around the borehole in the horizontal direction presents a"U"-shaped distribution;under the same discharge time,the maximum discharge radius of coal seam drilling increases with the increase of drilling diameter;the emission time,borehole diameter,and emission radius satisfy different functional relationships,and the coupling relationship between emission radius,borehole diameter,and emission time is derived from this.