上保护层开采下伏煤岩力学特性及瓦斯抽采效果

基于岩石破裂损伤理论和有限元计算方法,模拟保护层开采过程,下伏煤岩应力及变形特征,得出了下伏煤岩应力随保护层开采变化规律及被保护层煤层变形呈现压缩、膨胀、膨胀减小到稳定的变化规律,并在现场进行了工业性试验,考察了保护层开采过程,被保护层变形及煤层透气性变化,理论分析与现场测定基本吻合,依据研究结论,优化了被保护层卸压瓦斯抽采设计,通过被保护煤层卸压瓦斯抽采,残余瓦斯含量降到了2.33 m3/t,残余瓦斯压力降为0.35 MPa,均低于煤层突出临界值;被保护范围内煤层瓦斯抽采率达到44.8%;被保护层的瓦斯含量得到有效降低,消除了突出危险性,确保了被保护层的安全开采。

Underlying Coal and Rock Mechanics Features and Gas Drainage Effect of Upper Protective Seam Mining

Based on the rock fracture failure theory and the finite element calculation method,the protective seam mining process,underlying coal and rock stress and deformation features were simulated.With the protective seam mining variation law and the protected seam deformation,the underlying coal and rock stress would have a variation law from a compression,swelling,swelling reduced to stable.An industrial test was conducted at the mine site.The site investigation was made on the protective seam mining process,the protected seam deformation and the seam permeability variation.The theoretical analysis and the site measurement were basically the same.According to the study conclusion,the design on the pressure releasing and gas drainage of the protected seam was optimized.With the pressure releasing and gas drainage of the protected seam,the residual gas content was reduced to 2.33 m3/t,the residual gas pressure was reduced to 0.35 MPa and the residual gas content and the residual gas pressure were all lower than the seam outburst critical value.The seam gas drainage rate within the protected scope was reached to 44.8%.The gas content of the protected seam was effectively reduced,the outburst danger was eliminated and the safety mining of the protected seam could be ensured.