铁路隧道瓦斯等级划分的探讨

Discussion on Grade Division of Railway Tunnel Gas

研究目的:铁路隧道瓦斯等级划分,在勘察期间要准确定性很难,在施工中影响因素众多,争议较大,操作性相对较差,因此,如何既确保施工、运营安全,又节约工程投资,提高施工效率,缩短施工工期,科学、合理地确定瓦斯等级,值得进一步研究、实践。文章结合某铁路瓦斯隧道施工实例,以翔实的瓦斯检测资料,分析瓦斯涌出量、瓦斯浓度与施工安全的关系,提出新的观点。研究结论:目前《铁路瓦斯隧道技术规范》中以绝对瓦斯涌出量0.5 m3/min为高、低瓦斯等级划分界线的标准太低,使得一些可以按低瓦斯措施安全施工的隧道判定为高瓦斯等级,增加不必要的防爆、衬砌加强等措施,浪费工程投资;而在满足通风要求的情况下,以回风流中瓦斯浓度0.5%作为高、低瓦斯等级划分的标准更合适。

Abstract：Research purposes： It is very difficult to grade the gas of railway tunnel during the investigation because there are many influence factors to be involved in in the construction with the big dispute and poor operability. Therefore, it is worth doing the further study on how to grade the tunnel gas scientifically and reasonably to guarantee the construction and operation safety, save the construction cost, enhance the the construction efficiency and shorten the construction period. Combined with the construction practice of a railway gas tunnel, the analysis of the relation between the emission volume and concentration of gas and the construction safety was made and the new idea was presented on the base of using information on gas detection. Research conclusions： At present, according to the ＂ Technical code for Railway Gas Tunnel＂, the absolute gas emission volume of O. 5 m3/ min is regarded as the boundary standard for grading the high gas and low gas. This standard is too low so that some tunnels that could be built with the standard of the low gas are regarded as the high gas tunnel. In this way, the construction investment goes to waste by taking some unnecessary measures, such as explosion - proof and reinforcing the tunnel lining. On the premise of meeting the ventilation requirement, it is more appropriate to regard the gas concentration of 0.5% in the return air flow as the the standard for grading the high gas and low gas.