山区急倾斜煤层开采上覆岩层弯曲挠度预计

Prediction on bending deflection of overlying strata caused by steeply-inclined coal seam mining in mountainous area

为了研究山区急倾斜煤层开采上覆岩层的弯曲变形规律,建立了上覆岩层弯曲变形的力学模型,运用弹性力学中的薄板弯曲理论,推导了上覆岩层弯曲挠度的预计公式,利用此公式对上覆岩层的弯曲挠度进行了计算。研究结果表明:(1)由于山区急倾斜煤层覆岩的线性荷载的作用,岩板的弯曲挠度曲线不再具有对称性,岩板弯曲挠度的最大值偏向于岩板倾斜的下山方向;(2)岩板弯曲挠度随着采深的增大而增大,岩板弯曲挠度最大值出现的位置逐渐由下山方向向采空区中点移动,但是最大挠度出现的位置不会越过采空区中点而位于倾斜岩板的上山方向;(3)岩板弯曲挠度随着山地倾角的增大而增大,岩板挠度最大值出现的位置距离采空区中点越来越远;(4)岩板弯曲挠度随着煤层倾角的增大而减小,岩板弯曲挠度最大值出现的位置距离采空区中点越来越远。

In order to research the deformation mechanism of overlying strata caused by steeply-inclined seam mining in mountainous area,a mechanical model was established.Based on the thin plate bending theory in the elastic mechanic,the prediction formula was derived.And the bending deformation of overlying strata was calculated by this formula.Result shows that the curve of bending deflection of rock plate was no longer symmetrical and the maximum value of bending deflection of overlying strata was in favor of the downhill direction of declining of rock plate because of the effect of linearly load of coal seam overlying strata caused by steeply-inclined seam mining in mountainous area;it increased with the rise of the mining depth,and the location of the maximum value of it moved gradually from the downhill direction to the midpoint of mined-out space,but the location did not overcome the midpoint and reached the raising direction of inclining rock beam;it increased with the rise of the mutation angle and the distance between the location of the maximum value and the midpoint of mind-out space becomed further and further;it reduced with the rise of the coal bed pitch,and the distance between the location of the maxim value of rock plate bending deflection and the midpoint of mind out space becomed further and further.