缓倾斜煤层矿压显现规律的研究

Research on Strata-Pressure Behavior in Gentle Inclined Coal Seam

通过FLAC3D数值模拟软件模拟研究了缓倾斜煤层工作面的上覆岩层运移形态、沿工作面倾向采动应力分布规律,以及工作面回采后塑性区演化规律。得出:工作面回采过程中,工作面顶板受开采卸荷作用的影响,顶板出现垂直向下的卸载膨胀变形,引起顶板的离层、冒落,底板出现垂直向上的卸荷膨胀变形,且煤层顶板变形大于底板;随着工作面的不断推进,采空区顶板位移演化规律近似于椭圆形随轴比变化,当轴比接近1时,顶板下沉影响区域近似为“O”形;煤层回采后,工作面前后方出现应力集中现象,由于工作面不断推进,煤壁和采空区不断向前移动,导致工作面前后方支承应力是移动型支承应力;煤层回采后,工作面周边出现塑性区,且随着工作面回采距离的增加,塑性区面积逐渐增大。

The FLAC3D numerical simulation software was used to simulate the movement pattern of overlying strata, the distribution law of mining stress along the working face and the evolution law of plastic zone after mining. It is concluded that in the process of working face mining , the roof is affected by the effect of mining and unloading. The vertical deformation of the roof appears unloading and deforming vertically, causing the roof to separate from the ground and to fall off. The bottom plate appears vertical upward unloading and expansion deformation coal roof deformation is greater than the floor. With the continuous advancement of the working face, the evolution law of roof displacement in the goaf is similar to that of the ellipse with the axial ratio. When the axial ratio is close to 1, the influence area of the roof subsidence is approximately “O”. After coal seam mining, stress concentration occurs in front of and behind the work surface. Due to the continuous advancement of the work surface, the coal wall and the goaf continuously move forward, resulting in the stress of the bearing in the front and the back of the work surface being the movable support stress. After coal mining, the plastic zone appears around the working face, and with the increase of working face recovery distance, the plastic zone area increases gradually.