蒙华铁路阳山隧道瓦斯危害性评估研究

Study on Gas Hazard Assessment of Yangshan Tunnel on Inner Mongolia-Jiangxi Railway

蒙华铁路阳山隧道部分地段仰拱开挖后坑槽积水处多次发现瓦斯气体溢出现象,很大程度上给隧道施工带来了威胁。为确定阳山隧道瓦斯等级,文章在研究分析隧道工区煤系地层和浅层油气储层瓦斯赋存规律的基础上,利用突出危险性鉴定方法和基于钻孔瓦斯流量建立的涌出数学模型法分别对煤层和油气储层的瓦斯危害性进行了评估。结果表明,隧道工区揭露煤层位于瓦斯风化带,无突出危险性;隧道瓦斯的主要来源为隧道下部的长1油气储层,瓦斯通过构造破碎带或节理裂隙带涌出,隧道掌子面最大瓦斯涌出量为0.23 m^3/min,属低瓦斯隧道。

Gas emission occurred many times at the pondings of some sections after excavation of invert arch of Yangshan tunnel on Inner Mongolia-Jiangxi railway,threatening the tunnel construction to a large extent.In order to determine the gas grade of Yangshan tunnel,gas occurrence laws of coal measures and shallow oil and gas reservoirs in tunnel work area were studied,and the gas hazard of coal measures and shallow oil and gas reservoirs was evaluated by an identification method for gas burst hazard and drill-hole based gas volume model.The results show that the disclosed coal seam of tunnel work area is located at gas weathering zone and there is no risk of gas burst;the main source of tunnel gas is the Yanchang 1 oil and gas reservoir below the tunnel base,gas emits through tectonic fracture zone or joint fissure zone,the maximum gas emission at work face is 0.23 m^3/min,so this is a tunnel with low gas.