Study on Dynamic Evolution of Overburden Rock Movement and Mining-Induced Stress of Ultra-high Working Face

In order to explore the dynamic evolution of overburden rock movement and mining-induced stress an ultra-high working face, taking face a 2# thick coal seam in shallow mine field as engineering background, this paper analyzes distribution characteristics principal stress, mining characteristics, migration caving under different advancing distances calculates by FLAC3D numerical simulation software. The results show that when advances 200 m, concentration degree presents stable trend. variation gradient maximum are greater than those minimum while range peak ahead wall is smaller leading wall. With increase range, recovery gradually increases, higher stress. When 300 restores 66% initial value, only restored about 50%, surface subsidence reaches 2.5 m.