为了准确测定超前钻孔的有效排放半径,从煤层瓦斯流动规律的角度探讨了排放钻孔的影响因素,发现在一定煤层内,由于受条件限制,采用改变钻孔直径和长度及煤层透气性系数等方法提高排放效果是有限的。根据钻孔瓦斯涌出量与排放时间的关系,基于新集一矿的现场实际,通过计算钻孔瓦斯涌出量的变化率准确判定了超前钻孔的有效排放半径,得出在13-1煤层91 mm超前钻孔的有效排放半径为0.8 m。

In order to accurately measure the effective drainage radius of the advance borehole, from the view of the seam gas flow law, the influence factors of the gas drainage boreholes were discussed.In a certain seam, due to the restriction by the conditions, the gas drainage effect improved by the variation of the borehole dia meter and length, seam permeability coefficient and others was limited. According to the relationship between the gas emission value and drainage time of a borehole, b ased on the site practices in Xinji No.1 Mine, with the calculation on the variation rate of the gas emission in a borehole, an effective drainage radius of the advance bor ehole was accurately determined and the effective drainage radius of advance borehole with 091 mm in No.13-1 seam was 0.8 m.