关键词: 多煤层开采, 覆岩破坏, 冒裂带, 地表下沉

Abstract: Aiming at the problems of development of caving-fractured zone and mining influence，which occur during muti-coal seam mining in Daliuta Coal Mine，and through the similar simulation and the numerical simulation calculation，the overburden collapse，fracture development and surface subsidence law during the exploration of two main coal-seams were systematically studied.It is shown that rock strata of roof will directly fall from the surface after the broken of main overlying strata in shallow NO.2-2 coal seam.In the 5-2 coal seam，the caving and fractured zone caused by the once longwall and full-seam mining will develop into overlying goaf and form the water conductor of water inrush in working face.With the repeat mining strata，ground movement，and deformation value enlarged，the discontinuous damage of strata and surface increased.According to principal stress distribution obtained by numerical simulation results，overlying strata above goaf can be divided into three zones of two-way tensile stress zone，tension-compression stress zone and compressive stress zone.The principal stress state controls the formation and development of mining-induced fractures.Mining influence has a close relation with mining geometries，and surface subsidence value decrease with working face length and mining height reducing.Research results have important guiding significance for safety-mining and design in Daliuta and other coal mines with similar conditions.

Key words: Multi-coal seam mining, Strata failure, Caving and fractured zone, Surface subsidence