浅埋煤层采动诱发覆岩应力响应及地裂缝动态发育特征

Stress Response of Overlying Strata and Dynamic Development Characteristics of Ground Fissures Induced by Shallow Coal Seam Mining

为探究浅埋煤层综放采动诱发覆岩应力响应及地裂缝动态发育特征,利用UDEC软件对甘肃环县甜水堡矿区采煤过程中地裂缝的发育情况、应力变化情况进行数值模拟。研究表明:随着工作面的不断推进,地裂缝由下而上发育并且越发密集,采空区范围大到一定程度时,中部岩层被压实,临时性裂缝呈自闭合特征,永久性裂隙存在于采空区两侧。上覆岩层的下沉位移区域随工作面推进距离增大而增大,呈现出采空区两侧下降距离最少,越靠近采空区中部对称轴中心下降距离越深的趋势。采空区上覆岩层应力变化依次为应力集中、损伤变形、断裂坍塌到应力释放的过程。

To explore the stress response of overlying strata induced by shallow coal seam fully mechanized top coal caving mining and the dynamic development characteristics of ground fissures,UDEC software was used to numerically simulate the development and stress changes of ground fissures during the coal mining process in the Tianshuibao mining area of Huanxian County,Gansu Province.Research has shown that as the working face continues to advance,ground fissures develop from bottom to top and become increasingly dense.When the goaf reaches a certain extent,the middle rock layer is compacted,and temporary fissures exhibit a self-closing feature.Permanent fissures exist on both sides of the goaf.The subsidence displacement area in the overburden increases with the advancing distance of the working face,and the displacement in the overburden shows a trend of the minimum descent distance on both sides of the goaf,and the deeper the descent distance is towards the center of the symmetry axis in the middle of the goaf.The stress changes in the overlying strata of the goaf are sequentially the process of stress concentration,damage and deformation,fracture and collapse,and stress release.