关于瓦斯隧道揭煤突出危险性预测方法的探讨

Discussion on Prediction Method for Gas Outburst Hazard in Driving through Outburst Coal Seams in a Tunnel

当隧道穿过煤系地层时,准确可靠地预测揭煤工作面的突出危险性,是大断面隧道实现安全揭穿煤层的关键环节。以贵州某公路瓦斯隧道揭6号和2号煤层突出危险性预测为例,采用瓦斯含量指标与突出预测指标相互验证的方法,有效杜绝了因客观地质条件或因垂直距离不足,导致瓦斯压力指标测定结果不可靠,进而当选择瓦斯压力作为突出预测指标之一时,突出预测结果出现误判的缺陷,同时对现行规范存在的问题进行了探讨。实践表明,在垂直距离5 m处测定煤层瓦斯压力,垂直距离偏小,对于无烟煤,综合指标(D、K值)不宜作为突出预测的主要指标。

When a tunnel was driven through the coal-bearing strata, the accurate and reliable prediction of outburst hazard in the working face driving through an outburst coal seam is a key link to safely drive through outburst coal seams in the large- bore tunnel. By taking the prediction of outburst hazard in driving through No. 6 and No. 2 outburst coal seams in a highway tunnel in Guizhou Province as an example and using the inter-verificatlon of gas content index and outburst prediction index, unreliable measurement results of gas pressure which were caused by objective geologic conditions and insufficient vertical distance were effectively eliminated; then when gas pressure was chosen as one of the outburst prediction index, misjudgment of the outburst prediction index presented; in addition, discussion was made on the problems existing in the current specifications. The practice proved that when the gas pressure was measured at the place with 5 m vertical distance, the vertical distance was on the small side, and for anthracite, the comprehensive index （D, K value） should not be as the main index of outburst prediction.