深部大采高工作面沿空开采覆层运动规律研究

Research on overburden movement law of deep gob-side mining face with large mining height

以沿空开采为切入点,通过地质普查、理论分析、数值计算、现场检测等手段,分析工作面覆岩对工作面的作用特征。根据工作面覆岩作用的特点,提出并确定深部“三层”的判别方法及高度的确定。结果表明,覆岩内部形成3类施力岩层,“M_(k)”为工作面正常来压提供力源;“M_(j)”改变工作面应力释放向中-后位置偏移;“M_(y)”的均布载荷保证了工作面应力释放的位置。沿空开采覆岩形成的“拱”结构向采空区侧偏移,并不断向上演化。最终各工作面“拱”结构融合并形成对称结构。现场监测表明,418工作面的扰动范围及扰动应力值均大于416工作面;整个工作面最大压力释放的位置由中部迁移至沿空侧,机头的应力释放最小,为沿空工作面安全开采提供科学实践的依据。

By means of geological survey,theoretical analysis,numerical calculation and on-site detection,the action characteristics of overburden on mining face are analyzed.According to the characteristics of overburden action in working face,the discrimination method of deep“three layers”is put forward and its height is determined.The results show that there are three types of force-bearing strata in the overburden,among which“M_(k)”provides the force source for normal pressure of the working face,“M_(j)”shifts the stress release to the middle back position of the working face,and the“M_(y)”uniform load ensures the stress release position at the working face.At the same time,the“arch”structure formed by gob-side mining drifts to the goaf side and continuously evolves upward.Finally,the“arch”structure of each working face merges and forms a symmetrical structure.The field monitoring shows that the disturbance range and disturbance stress value of 418 working face are greater than 416 working face,the maximum pressure release position of the whole working face moves from the middle to the gob-side,and the stress release of the head is the smallest,which provides a scientific basis for the safe mining of the gob-side working face.