Coalbed methane (CBM) is not only the material cause of gas explosion and coal‐gas outburst disasters during underground coal mining, but also a kind of clean energy. Coal permeability is an important parameter for CBM drainage. Although many coal permeability models have been developed in the past decades to describe the permeability evolution characteristics under elastic state, few of them could explain the permeability behavior of the mining‐disturbed coal which is often the situation of CBM drainage during underground coal mining. The paper analyzed the mechanical factors affecting the damage‐permeability characteristics of mining‐disturbed coal, proposed the concept of the deviatoric stress ratio (DSR), and then established the statistical damage and permeability evolution models based on DSR. Results show that the deformation and damage of coal is controlled by the deviatoric stress and minimum principal stress. The plastic damage degree of coal mass becomes more serious with DSR increase, which leads to the improvement in permeability. The damage constitutive model was established based on the Weibull distribution function and DSR, and then the permeability model of mining‐disturbed coal was built combining the Kozeny–Carman equation. The acoustic emission (AE) and permeability experiments of the loading and unloading coal sample were conducted. After normalizing and fitting the accumulative AE counts, the damage and permeability evolutions with respect to DSR were found out. The model‐predicted permeability could match with the experiment results, verifying the reliability of the theoretical permeability model. The purpose of this paper is to provide a new approach for modeling damage and permeability of mining‐disturbed coal based on DSR. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.

中文翻译：

---

采矿扰动煤的破坏与渗透性演化：模型与验证

煤层气（CBM）不仅是地下煤矿开采过程中瓦斯爆炸和煤与瓦斯突出灾害的根本原因，也是一种清洁能源。煤的渗透率是煤层气排放的重要参数。尽管在过去的几十年中已经开发了许多煤渗透性模型来描述弹性状态下的渗透性演化特征，但是很少有模型可以解释受开采干扰的煤的渗透性行为，而这通常是地下采煤过程中煤层气排放的情况。分析了影响开采扰动煤破坏渗透率特征的力学因素，提出了偏应力比（DSR）的概念，并建立了基于DSR的统计破坏与渗透率演化模型。结果表明，煤的变形和破坏受偏应力和最小主应力的控制。随着DSR的增加，煤块的塑性破坏程度变得更加严重，从而导致渗透率的提高。基于Weibull分布函数和DSR建立了损伤本构模型，然后结合Kozeny-Carman方程建立了开采扰动煤的渗透性模型。进行了装煤样品和卸煤样品的声发射（AE）和渗透率实验。对累积的AE计数进行归一化和拟合后，发现了相对于DSR的破坏和渗透率演变。该模型预测的渗透率可以与实验结果相匹配，验证了理论渗透率模型的可靠性。本文的目的是提供一种基于DSR的扰动煤层破坏和渗透率建模的新方法。©2021化学工业协会和John Wiley＆Sons，Ltd.