极近距离厚煤层交错采场覆岩破坏数值模拟

Numerical Simulation of Overburden Failure Feature for Staggered Stopes in Close Distance Thick Coal Seam

为了研究极近距离厚煤层交错采场覆岩破坏的规律,采用压力拱理论对采场开采过程中的覆岩破坏结构的演化进行了分析,通过FLAC3D建立开采模型,得出下部工作面距上部采空区较远时,其覆岩破坏结构具有相对的独立性,当推进一定距离时,应力集中系数1.8左右,垮度和拱高趋于稳定;当下部工作面接近上部采空区时,上下距离在40 m左右范围内,集中系数为3.3左右,随距离减小,集中系数继续加大,易导致两结构拱贯通;当下部工作面位于上部采空区下时,处于卸压状态,应力集中系数较小,即将穿过采空区时,应力集中系数为2.3,主要是因为两采场开采空间的叠合。

In order to research the overburden failure laws for staggered stopes in extremely close thick coal seam, the evolution of over- burden failure structure in the process of mining is analyzed by pressure arch theory. Through FLAC^3D mining model is established, and the following conclusions are got, including that when the lower face is far away from the upper goal, the overburden failure structure is relative independence; when the face advances a certain distance, the stress concentration factor is 1.8, and the span and the height of arch is stable; when the lower tace closes to the upper goal, and the distance is in about 40 m, concentration coefficient is 3.3, with the decrease of distance, the concentration coefficient continually increases, which easily lead to the transfixion of two structure arches; when the lower face is on the top of goal, the face is in discharging pressure condition, stress concentration factor is small; when the face pass through the goaf, stress concentration coefficient is 2.3, which is mainly because of the stope mining superposition of two