Abstract The 100-year global warming potential of methane is 28 times higher than the value of carbon dioxide. Accurate gas content measurement is a precondition of coal mine reconstruction and extension designs for reducing methane emission due to that in these scenarios the stress and gas pressure distributions were unpredictably disturbed by previous mining activities. Longer roadway exposure time induce lower gas content and high measurement error. In this study, a coupling model considering the influence of gas transport, solid mechanics, and permeability evolution was established to predict the gas pressure distribution in coal seams. Based on this model, the influence of the roadway exposure time on the gas pressure distribution in an extended mine, Hulonggou Mine, was numerically studied with the software of COMSOL. The results show that the stress concentration area near the roadways can reduce the rate of gas emission. In addition, the gas pressure relief zone becomes increasingly larger as the emission time increases. For the studied coal seam, the boundary of the gas pressure relief zone is about 25–30 m to the center line after 25 years’ gas emission. At last, actual gas content measurements validated the simulated results. The results can help scholars properly predict the gas content and design the gas drainage plans for coal seams that have been excavated for several years.

中文翻译：

---

巷道暴露时间对改扩建矿井瓦斯含量测量精度的影响

摘要 甲烷的 100 年全球变暖潜能值是二氧化碳值的 28 倍。准确的瓦斯含量测量是减少甲烷排放的煤矿改造和扩建设计的前提，因为在这些场景中，应力和瓦斯压力分布会受到以前的采矿活动不可预测的干扰。较长的道路暴露时间会导致较低的气体含量和较高的测量误差。在本研究中，建立了考虑气体输运、固体力学和渗透率演化影响的耦合模型，以预测煤层中的瓦斯压力分布。基于该模型，利用COMSOL软件数值研究了巷道暴露时间对虎龙沟煤矿瓦斯压力分布的影响。结果表明，靠近巷道的应力集中区可以降低瓦斯排放率。此外，随着排放时间的增加，气体压力释放区变得越来越大。对于所研究的煤层，瓦斯泄压带的边界在瓦斯排放 25 年后距中心线约 25-30 m。最后，实际气体含量测量验证了模拟结果。研究结果可帮助学者对已开挖多年的煤层正确预测瓦斯含量和设计瓦斯抽采方案。瓦斯泄压带边界距中心线约 25~30 m，经过 25 年的瓦斯排放。最后，实际气体含量测量验证了模拟结果。研究结果可帮助学者对已开挖多年的煤层正确预测瓦斯含量和设计瓦斯抽采方案。瓦斯泄压带边界距中心线约 25~30 m，经过 25 年的瓦斯排放。最后，实际气体含量测量验证了模拟结果。研究结果可帮助学者对已开挖多年的煤层正确预测瓦斯含量和设计瓦斯抽采方案。