基于有效应力原理分析了煤体吸附瓦斯对煤体强度的影响,提出应用煤体单轴抗压强度衰减比k_σ表征瓦斯压力变化对煤体强度的影响;应用数值分析方法研究了煤体瓦斯抽采前后煤壁前方煤体应力、屈服破坏范围的变化。结果表明,抽采期间,煤壁前方煤体应力峰值处于“动态移动”状态,致使煤壁前方的屈服破坏区间同时发生移动,水泥封孔段由受压转为应力卸载状态而发生膨胀破坏,在封孔段水泥与煤壁之间形成松动漏气通道,孔外空气将沿该漏气通道进入孔内,使抽采浓度降低。为提高带压封孔方法的封孔效果,应科学判定抽采前期煤体应力峰值区间,并考虑抽采期间煤体“应力峰值移动”的影响,在应力峰值区间适当向两侧延伸封孔段长度,注重封孔器材和封孔材料的研制和选择。 Based on the principle of effective stress, the influence of gas adsorbed by coal on the strength of coal was analyzed. The effect of the variation of gas pressure on the strength of coal was characterized by the application of uniaxial compressive strength attenuation ratio k_σ. The numerical analysis was used to study the effect of gas drainage Coal mining before and after the coal wall in front of the stress, yield failure range changes. The results show that the stress peak of the coal in front of the coal wall is in a state of “dynamic movement” during the extraction period, causing the yield failure zone in front of the coal wall to move at the same time. The cement sealing section expands from compression to stress unloading Damage, in the sealing section of the formation of loose cement and coal wall leaks, air outside the hole along the leak into the hole, so that the concentration of mining to reduce. In order to improve the sealing effect of pressure sealing method, the peak stress range of coal body in the first stage of extraction should be scientifically determined, and should be properly extended to both sides in the stress peak range in consideration of the influence of the “peak stress” during coal mining. Sealing section length, focusing on sealing equipment and sealing material development and selection.