铁路隧道高瓦斯突出段安全施工关键技术

Key Technologies for Safety Construction of High Gas Outburst Section of Railway Tunnel

渝黔铁路新凉风垭隧道洞身穿越二叠系龙潭组煤系地层,有可采煤层9层,最大瓦斯压力1.5MPa,是煤系地层高瓦斯具突出性高风险的双线铁路隧道。为确保施工安全,在隧道施工过程中修改完善了瓦斯预测及验证设计,详细提出区域预测与验证、工作面预测与验证的具体要求,以及各个预测及验证步骤实施的位置和验证方法。为缩短抽放时间采用了水力压裂增透技术,达到了很好的抽放效果,并制定多煤层集中抽采结合下导坑自然排放的瓦斯抽排放方案。另引入了六大安全保护系统,有效地确保了工期及施工安全。

New Liangfengya tunnel on Chongqing-Guizhou line crossing the Longtan formation coal measure strata of Permian,there are 9 layers of workable seam,maximum gas pressure 1.5 MPa,it is a double line railway tunnel with high outburst risk in coal measure strata.In order to ensure the safety of construction,in the process of tunnel construction,the gas prediction and verification design is improved,the specific requirements for regional prediction and verification,and the prediction and verification of the working face as well aslocation and verification methods for each prediction and validation step are presented in detail.In order to shorten the drainage time,hydraulic fracturing technology is applied in construction,and a good drainage effect is achieved,also the gas drainage scheme of multi-seam concentrated drainage combined with natural emission of the downside heading,in addition,six security protection systems are introduced to effectively ensure the construction period and construction safety.