Although gas drainage technology has greatly developed, gas concentration and utilization rates are still very low, resulting in substantial quantities of low concentration gas emissions in coal mine. To study the roles of suction pressure on gas drainage, a mathematical model is developed in this study for coupled gas migration and coal deformation based on a dual-porosity medium. The simulation results reveal the initial gas production is mainly contributed by the seepage in the fracture, and then the dominating factor rapidly transitions to diffusion which provides relatively stable gas production in most drainage time. In addition, the increase in gas production is tiny while the gas concentration clearly decreases because of air leakage as the suction pressure increases. Therefore, a concentration-based suction pressure regulating method is proposed to extend the time period of effective gas drainage and increase the gas utilization rate through adjusting the suction pressure of the bedding borehole. Field tests were performed to constrain the gas drainage process under different suction pressures, and the results gained verify the effectiveness and applicability of this method. This study proves that the concentration-based suction pressure regulating method may be a promising technology to realize safe, economical and efficient underground gas drainage in coal mines in the future.

尽管瓦斯抽放技术得到了很大的发展，但瓦斯浓度和利用率仍然很低，导致煤矿中大量的低浓度瓦斯排放。为了研究吸力压力在瓦斯抽放中的作用，本研究建立了一个基于双孔隙度介质的耦合瓦斯运移和煤变形的数学模型。模拟结果表明，初始产气主要是由裂缝中的渗漏引起的，然后主要因素迅速转变为扩散，这在大多数排水时间内提供了相对稳定的产气量。另外，随着吸气压力的增加，由于空气泄漏，气体产量的增加很小，而气体浓度却明显降低。所以，提出了一种基于浓度的吸入压力调节方法，通过调整顺层井眼的吸入压力来延长有效瓦斯抽采的时间，提高瓦斯利用率。为了限制不同抽气压力下的瓦斯抽采过程，进行了现场试验，所得结果验证了该方法的有效性和适用性。这项研究证明，基于浓度的吸入压力调节方法可能是将来实现煤矿安全，经济，有效的地下瓦斯抽采的有前途的技术。为了限制不同抽气压力下的瓦斯抽采过程，进行了现场试验，所得结果验证了该方法的有效性和适用性。这项研究证明，基于浓度的吸入压力调节方法可能是将来实现煤矿安全，经济，有效的地下瓦斯抽采的有前途的技术。为了限制不同抽气压力下的瓦斯抽采过程，进行了现场试验，所得结果验证了该方法的有效性和适用性。这项研究证明，基于浓度的吸入压力调节方法可能是将来实现煤矿安全，经济，有效的地下瓦斯抽采的有前途的技术。