Coalbed methane is a double-edged sword with two attributes of energy and hazard in coal mines. Gas drainage is the most direct and effective measure for gas recovery and disaster prevention in coal mines, which is seriously affected by the mechanics and seepage characteristics of coal. In this work, we experimentally simulated the triaxial compression and gas depletion processes using both tectonic coal and intact coal. The mechanics and seepage characteristics of tectonic and intact coal under the coupling effect of stress and gas pressure were analyzed and compared. The results show that during the triaxial compression, the damage stress and peak stress of tectonic coal is only half that of intact coal, while their compaction stress or residual stress are almost the same. Meanwhile, the permeability recovery value after tectonic coal failure is very limited, even smaller than that of intact coal, although its primary permeability is much larger than that of intact coal. On the contrary, the permeability recovery value after intact coal failure is more than twice of its primary permeability. During the gas depletion, the rebound gas pressure of tectonic coal is smaller than that of intact coal, and the permeability of tectonic coal is one order of magnitude larger than that of intact coal before the gas pressure drops to 2 MPa. The broken of tectonic coal and the low permeability of intact coal may be the two principal reasons. Therefore, in the tectonic coal area, the gas extraction time at high gas pressure stage should be stabilized, while in the intact coal area, the gas extraction time at low gas pressure stage should be increased, and the coal permeability enhancement measures should be combined to achieve the goal of high and stable production of coalbed methane.

中文翻译：

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构造完整含煤瓦斯力学与渗流特性的实验研究

煤层气是一把双刃剑，在煤矿中具有能源和危险两个属性。瓦斯抽放是煤矿瓦斯回收和防灾最直接，最有效的措施，它受到煤炭力学和渗流特性的严重影响。在这项工作中，我们通过实验模拟了构造煤和完整煤的三轴压缩和瓦斯耗竭过程。分析并比较了应力和气压耦合作用下构造煤和原煤的力学及渗流特性。结果表明，在三轴压缩过程中，构造煤的破坏应力和峰值应力仅为完整煤的一半，而压实应力或残余应力几乎相同。与此同时，构造煤破坏后的渗透率恢复值非常有限，尽管其一次渗透率远大于完整煤，但甚至小于完整煤。相反，完好的煤破坏后的渗透率恢复值是其一次渗透率的两倍以上。在耗气期间，构造煤的回弹气压小于完整煤的回弹气压，并且在气压降至2 MPa之前，构造煤的渗透率比完整煤的渗透率大一个数量级。构造煤的破裂和完整煤的低渗透性可能是两个主要原因。因此，在构造煤区，应稳定高气压阶段的瓦斯抽采时间，而在完整煤区，