祁连山2#隧道高瓦斯段监测处置和通风措施初探

Discussion on monitoring,disposal and ventilation measures of Qilian Mountain 2# Tunnel

隧道作为地下工程,在勘察设计阶段将会遇到一些不可控和不可预见的因素,瓦斯就是其中之一。青海省祁连山2#隧道在掘进过程中发现了瓦斯等有害气体,成为青海省内第一座高瓦斯公路隧道。瓦斯出现后,对工程进度、施工安全都带来了较大的困扰。在保证安全、质量的前提下,依据《公路瓦斯隧道设计与施工技术规范》(JTG/T 3374-2020)并结合《铁路瓦斯隧道技术规范》(2019)从严提出针对性的处置方案。针对洞内相关段落高瓦斯及硫化氢等气体提出处置措施,明确设防段落和设防等级。在制定方案时,综合考虑洞内同时作业人数、最小风速、爆破时需要排除的炮烟量、机械设备总功率和瓦斯涌出量等因素,经过风量和瓦斯涌出量的计算,科学合理地配置通风设备、确定通风方案。在现场施工中以工程地质分析为基础,通过粗查、精查、物探、钻探等手段,结合最新取得的地质调查和勘察资料进行综合判定,使祁连山2#隧道的施工安全和质量处于可控状态。实践表明,隧道施工中出现高瓦斯并不可怕,只要及时制定科学合理的应对措施,坚持勤观测、早预判的原则,就能有惊无险地通过高瓦斯工区施工段。本文件拟通过总结祁连山2#隧道高瓦斯及硫化氢等气体的一些处置措施,为高海拔地区高瓦斯隧道施工和造价控制提供参考。

As an underground project,tunnels will encounter some uncontrollable and unpredictable factors in the survey and design stage,of which gas is one.Gas and other harmful gases were found in the excavation of Qilian Mountain Tunnel 2# in Qinghai Province,making it the first high gas highway tunnel in Qinghai Province.After the emergence of gas,it has brought great difficulties to the project progress and construction safety.On the premise of ensuring safety and quality,the targeted disposal scheme is strictly proposed according to the Technical Code for Design and Construction of Highway Gas Tunnel(JTG/T 3374-2020)and in combination with the Technical Code for Railway Gas Tunnel(2019).Put forward treatment measures for high gas,hydrogen sulfide and other gases in relevant sections of the tunnel,and define the fortification sections and levels.In formulating the scheme,the number of simultaneous workers in the tunnel,the minimum wind speed,the amount of blasting smoke to be removed during blasting,the total power of mechanical equipment,the amount of gas emission and other factors shall be comprehensively considered.After the calculation of air volume and gas emission,the ventilation equipment shall be scientifically and reasonably configured and the ventilation scheme shall be determined.On the basis of engineering geological analysis,the construction safety and quality of Qilian Mountain Tunnel 2# are under control through comprehensive judgment based on the latest geological survey and exploration data obtained by means of rough survey,intensive survey,geophysical exploration and drilling.Practice shows that the occurrence of high gas in tunnel construction is not terrible.As long as scientific and reasonable countermeasures are formulated in time and the principle of frequent observation and early prediction is adhered to,the construction section of high gas work area can be passed without danger.This document is intended to provide reference for high gas tunnel construction and cost control in high altitude areas by summarizing some disposal measures for high gas,hydrogen sulfide and other gases in Qilian Mountain Tunnel 2#.