含矸煤层煤壁稳定性夹矸厚度效应研究

Study on effect of gangue thickness on stability of coal wall ofworking face gangue-bearing coal seam

为了解夹矸厚度对含矸煤层煤壁稳定性的影响,采用理论分析与数值模拟相结合的方法,推导出夹矸层剪切破坏力学模型,进而建立含矸煤层煤壁稳定性数值模型,分析不同夹矸厚度下的煤壁前方水平位移、垂直应力的空间分布特征。结果表明:煤壁前方产生失稳影响区主要位于夹矸层周围,形成以夹矸层为中心的凸出区域;夹矸厚度较小时,夹矸层呈现出多块体联合破坏形态,而夹矸厚度较大时,夹矸层出现单块体逐个破断现象;力学分析得知:夹矸层破坏面发生剪切破坏的危险系数随着夹矸厚度的增大而逐渐减小,数值模拟结果与理论分析一致。

In order to recognize the influence of gangue thickness on the stability of the coal wall of gangue-bearing coal seam,theoretical analyses were used to derive a mechanical model for the shear damage of the entrapped gangue layer,numerical modeling of coal wall stability in gangue-bearing coal beds was developed,spatial distribution characteristics of horizontal displacement and vertical stress in front of coal wall under different thickness of gangue were analyzed.The results show that the front of the coal wall produced instability impact area is mainly located around the gangue layer,with the formation of the gangue layer as the center of the protruding area.When gangue thickness is small,the gangue layer presents a multi-block body joint damage,and when gangue thickness is larger,the gangue layer appears to be a single block body broken one by one.Mechanical analysis shows that the risk factor of damage to the gangue layer gradually decreases with the increase of gangue thickness,and the numerical simulation results are consistent with the theoretical analysis.