上保护层开采下伏煤层卸压变形及应力分布

Decompression Deformation and Stress Distribution of Underlying Coal Seam in Upper Protective Coal Seam Mining

为掌握上保护层开采过程中下伏煤层卸压破坏变形及应力分布规律,提高上保护层开采预防下伏煤层煤与瓦斯突出的效果,以河南平顶山四矿己16-17煤层为对象,基于PoytingThomson模型构建煤岩体蠕变动力学模型,借助Comsol Multiphysics5.2软件对下伏煤层膨胀变形及卸压分布规律进行仿真模拟和工程验证。结果表明:随着上保护层工作面的推进(由10 m推进至60 m),下伏煤层左右两侧分别形成98.5°及114°卸压角,横向塑性变形量增至最大约为216 m;下伏煤层呈塑性变形→形变恢复的变化特征,说明上保护层的开采有助于下伏煤层瓦斯卸压通道的形成,有利于下伏煤层瓦斯的抽采。

To grasp the pressure and failure deformation and stress distribution of the underlying coal seam during the mining process of the protective coal seam,and improve the effect of the upper protective coal seam mining to prevent the coal seam and gas outburst of the underlying coal seam,this paper takes theⅥ16-17 coal seam of Pingdingshan No.4 mine in Henan Province as the object.Based on the Poyting-Thomson model,the creep dynamics model of coal and rock mass is constructed.The Comsol Mutiphysics 5.2 is used to simulate the deformation and deformation law of the underlying coal seam and the engineering verification.The results show that with the advancement of the upper protective layer working face(from 10 m to 60 m),the left and right sides of the underlying coal seam form a relief angle of 98.5°and 114°respectively,and the lateral plastic deformation increases to a maximum of about 216 m;the coal seam is characterized by plastic deformation to deformation recovery,which indicates that the exploitation of the upper protective layer contributes to the formation of gas depressurization channels in the underlying coal seam,which is beneficial to the extraction of gas in the underlying coal seam.