Study on the Movement Law of Overburden Strata as Multiple Working Face Crossing the Coal Pillar

In view of the problems such as coal wall and roof are easy to suffer excessive pressure when multiple working face crossing the coal pillar, this paper takes the first multiple working face of Baigou Coal Industry as the research background, the method of combination of analog simulation and numerical simulation is adopted, the deformation and failure of roof, as well as the law of motion evolution are studied in the whole dynamic process when multiple working face crossing the coal pillar. The results show that the maximum caving height on both sides of the coal column increases with the advance of the mining face, and the stability of the coal column increases from weak to strong, the structure of top coal pillar changes from the original "inverted trapezoid" to the "inverted triangle". The order of variation of roof support structure is as follows: "coal pillar" type, "hydraulic support - residual pillar" type, "hydraulic support - old mining area gangue" type.