基于体积应变含瓦斯煤体渗透特性研究

Research on Permeability of Gas-Filled Coal Based on Volumetric Strain

为获得含瓦斯煤体渗透特性的采动响应特征,应用理论分析、数值模拟和现场试验相结合的方法对含瓦斯煤体渗透率的采动响应机制进行了研究。依据孔隙率的定义,以KozenyCarman方程为桥梁,建立了基于体积应变的含瓦斯煤体渗透率的采动响应模型。基于渗透率采动响应模型,采用COMSOL Multiphysics模拟了煤层开采过程中渗透率的变化规律,并在现场开展了渗透率的采动响应研究。结果表明:采动是影响煤体渗透率的主要因素,煤体体积应变、渗透率和瓦斯流量在采动过程中具有基本一致的变化规律,随着工作面的临近,煤体膨胀变形、渗透率逐渐增大,在靠近工作面处达到最大值;距工作面相同位置处,回风巷侧煤体的瓦斯流量大于运输巷侧,越靠近工作面煤体的渗透性越大。

In order to obtain the mining response characteristic of permeability of gas - filled coal, the paper studied the mining response mechanism of permeability combining theoretical analysis with numerical simulation and field test. The mining response model of permeability was established using the definition of porosity and Kozeny - Carman equation based on volumetric strain, the variation of the permeability in the process of coal mining was simulated using COMSOL Multi - physics based on the mining response model of permeability and the mining response of permeability in the field was studied. The results show that, mining is the key factor affecting coal permeability, the volumetric strain, permeability and gas flow have the consistent variation in the process of mining. The swelling deformation of coal and permeability increases gradually as the approaching of the working face and reaches a maximum near the working face. The gas flow of the return airway side seam is greater than that of haulage roadway at the same location away from the face, and the coal permeability increases as is closer to the working face.