急倾斜多煤层上保护层保护范围的数值模拟

Numerical simulation for protection scope of upper protective seam in steeply inclined multi-coal seam

针对急倾斜煤层上保护层俯伪斜开采的保护范围划定问题,采用三维快速拉格朗日法,通过模拟上保护层俯伪斜开采后被保护层的应力场及变形场的动态发展过程,确定了随着上保护层工作面的推进,被保护层的垂直层理面应力和煤层变形规律;根据上保护层开采后的应力卸压保护准则和煤层变形保护准则,确定了上保护层沿走向和倾向的保护范围.研究表明,急倾斜煤层俯伪斜上保护层开采后,上保护层俯伪斜采煤法沿倾向上、下边界的卸压角分别为81.5和74°;沿走向的卸压角在倾向上呈非均匀分布,大小为30~52,°伪倾斜工作面中部的走向卸压角最大,为52°.数值模拟结果与现场考察结果比较接近.

Aimed at the problem on protection scope demarcation of upper steeply inclined protective seam of pitching oblique mining, based on the method of three dimensional fast Lagrange method, the dynamic development process of stress distribution and deformation of protected coal seam with exploitation of steeply inclined protective seam of pitching oblique mining were simulated using FLAC3D. Besides, the law of the stress and deformation normal to the protected coal samdwieh were analyzed with the advance of upper protective layer eoalface ; based on the protection rule of pressure-relieving and normal deformation of protected seam, the pressure-relief angles on the dip and strike were ascertained. The result shows that the protection angles on the upper and bottom dip direction are 81.5 and 74°respectively; while the protection angles on strike direction are variant ranging from 30 to 52°; the most largest pressure-relieving angle is in the middle pitching oblique eoalface. Through comparison, the result of the numerical simulation is close to the field investigation.