保护层开采保护范围的确定及影响因素分析

Determination of Protection Scope and Analysis of Influencing Factors in Protective Layer Mining

针对煤层下保护层开采保护范围划定及影响性问题,利用有限元分析软件ANSYS生死单元模拟保护层开采,探究随着保护煤层工作面的推进,被保护煤层垂直于煤层层理面的应力和变形规律;根据保护层开采应力卸压保护准则和煤层变形保护准则,确定被保护层沿倾向和走向的保护范围,同时对保护层保护效果的影响性因素进行分析。通过对某煤矿保护层开采保护范围的分析结果发现,被保护煤层倾向上部卸压角为60.32°,倾向下部卸压角为43.86°。走向卸压角在倾向各个位置呈现非均匀分布,最大卸压位置为走向中部附近,最大卸压角为54.46°。分析保护层保护效果的影响性因素可知,当煤层倾角较小时,采动应力判别准则较应变准则所得的卸压保护角偏于保守,较为安全。

For the problems of the delimitation and influence of protection scope in lower protective coal seam mining,the finite element analysis software ANSYS is used to simulate the mining of the protective layer,and the stress and deformation laws of the protected coal layer perpendicular to the coal bedding surface are explored as the working surface of the protected coal layer advances;according to the protection criterion of mining stress and pressure relief and the protection criterion of coal seam deformation,the protection scope of the protected layer along the dip and strike is determined,and the influencing factors of the protection effect of the protected layer are analyzed.Through the analysis of the protective range of a coal mine,the upper pressure relief angle of protected coal seam inclination is 60.32°,and lower pressure relief angle of protected coal seam inclination is 43.86°.The pressure relief angle of strike presents non-uniform distribution in all the dip positions,the maximum pressure relief position is near the central strike,and the biggest pressure relief angle is 54.46°.By analyzing the influencing factors of protective effect of protective layer,it can be seen that when the inclination angle of coal seam is small,the discrimination criterion of mining stress is more conservative than that of strain criterion,and the protective angle of pressure relief is relatively safe.