隧道施工高瓦斯运移扩散规律及防治措施研究

Research on the Law of High Gas Migration and Diffusion and Its Control Countermeasures During Tunnel Construction

以贵州省金沙经仁怀至桐梓高速公路梭萝坪隧道为研究对象,运用现场实测的方法,研究瓦斯的赋存特征以及施工阶段的运移扩散规律,并提出相应的防治措施。结果表明:隧道穿越煤层段具有瓦斯含量高、瓦斯压力大的特点,瓦斯浓度随着深度的增加而不断增加;瓦斯压力释放在Ⅰ阶段呈现双曲线降低趋势,在Ⅱ阶段趋于稳定和收敛,瓦斯压力的释放速率、收敛值与贯穿煤层的空间位置相关;在爆破后50 min内,瓦斯的浓度经历先增加后降低最后稳定的过程,拱顶位置的瓦斯浓度峰值最大,下降速率最快,拱腰和拱底位置的浓度峰值和下降速率相近;针对高瓦斯浓度的隧道施工提出了基于KJ73X型矿井综合安全监控系统对瓦斯浓度进行监控;采用ZWSJ-A隧道车辆瓦斯监控装置对机械设备进行防爆改装;在施工工艺方面提出“错洞施工、分段探测”的施工方法降低瓦斯的突涌。

Taking the Suoluoping Tunnel of the Jinsha to Tongzi Expressway in Guizhou Province as the research object,using on-site measurement methods,the occurrence characteristics of gas and the migration and diffusion laws during construction stage are studied,and corresponding prevention and control measures are proposed.The results show that the tunnel crossing the coal seam section has the characteristics of high gas content and high gas pressure,and the gas concentration continuously increases with the increase of depth;the gas pressure release presents a hyperbola decreasing trend in Phase I,and tends to be stable and convergent in Phase II.The release rate and convergence value of gas pressure are related to the spatial position of the coal seam;within 50 minutes after blasting,the concentration of gas undergoes a process of first increasing,then decreasing,and finally stabilizing.The peak concentration of gas at the top of the arch is the highest and the rate of decline is the fastest,while the peak concentration and rate of decline at the waist and bottom of the arch are similar;a KJ73X mine comprehensive safety monitoring system is proposed to monitor gas concentration during tunnel construction with high gas concentration;using the ZWSJ-A tunnel vehicle gas monitoring device for explosion-proof modification of mechanical equipment;in terms of construction technology,the construction method of“staggered hole construction and segmented detection”is proposed to reduce gas outburst.