为解决逆断层工区浅层天然气频繁涌出的问题，依托成都轨道交通30号线工程，通过CH4短期监测试验、CH4补给试验、CH4长期监测试验和气相色谱试验，探索逆断层工区浅层天然气的涌出、补给、赋存特征和聚集能力。结果表明: 1）活动逆断层区域浅层天然气短期聚集能力强、涌出量大、补给速度快，但补给的持续性较差。2）在休止期逆断层的破碎带区域中，浅层天然气短期聚集能力强、涌出量大、补给效率和持久稳定性好，长期的敞孔通风措施可以有效降低该区域浅层天然气的短期聚集能力和涌出量；而在裂隙发育带中浅层天然气聚集能力弱、涌出量小、补给效率和持久稳定性差，长期敞孔通风条件可以排放掉钻孔周围的绝大部分浅层天然气。3）休止期逆断层中，浅层天然气在破碎带区域连续分布，在裂隙发育带范围内以气囊的方式不均匀分布。4）浅层天然气主要赋存在逆断层方圆1~2 km，气体体积分数随埋深增加而增大，CH4与其他烃类气体的比值（C1/C2+）随埋深增加而减小。
To avoid frequent outbursts of shallow natural gas in
the reverse fault area, a case study of the Chengdu metro line 30 is conducted,
and CH4 shortterm and longterm monitoring tests, CH4 recharge test,
and gas chromatography test are employed to explore the characteristics of gas
outburst, recharge, occurrence, and accumulation capacity of shallow gas in
reverse fault areas. The results reveal the following: (1) The shortterm accumulation of shallow natural gas in the active reverse fault
area is strong, outburst volume is large, and recharge speed is high, but the
sustainability of the replenishment is poor. (2) In the broken zone of the
static reverse fault, the shortterm accumulation of
shallow natural gas is strong, outburst volume is large, recharge efficiency
and sustainability are good, and longterm ventilation
measures can effectively reduce the shortterm
accumulation ability and shallow natural gas outbursts in this area. However,
in the fractured zone, shallow natural gas has weak accumulation ability, small
outburst volume, poor recharge efficiency and sustainability, and most of the
shallow natural gas around the borehole can be discharged by longterm ventilation. (3) In the static reverse fault, shallow natural
gas is continuously distributed in the broken zone and unevenly distributed in
the form of air bags within the fracture zone. (4) Shallow natural gas mainly
accumulates within 1~2 km around the reverse fault. With the increase in depth,
the concentration of gas increases, whereas the ratio of methane to other
hydrocarbon gases (C1/C2+)
decreases.
