Analysis on Construction Loading at Surface Ground to Roof Deformation Failure Effect in Goaf of Underground Mining

Under the loading role of the construction at the surface ground,when the safety thickness of the roof over the goaf in the underground mine under the surface mine was not sufficient,the roof over the goaf would occur sudden fallings and the surfaceground subsidence which would be a potential danger to the operation personnel and the mining and excavation equipment at the place over the goaf.Based on the background of the goaf area under Antaibao Surface Mine,the 3D numerical calculation model established with FLAC3D was applied to analyze the roof deformation and failure effect in the goaf under the loading role of the surface ground mechanical constructions at the surface ground above the goaf with different mining depths.The goaf failure mode of the room and pillar mining and the judgment of the roof stability in the goaf were provided.With the calculation analysis on the damage and failure area,the stress concentration degree and main stress value variation of the goaf roof and goaf pillars under the surface mine,and with the displacement variation curves of each monitoring and measuring station,the deformation failure process and the damage evolution features of the goaf roof and goaf pillar were revealed under the loading role of the surface ground mechanical constructions in order to ensure the safety construction operation.