Research on Pressure Relief Effects of Protective Layer Under the Conditions of Coal Seam Group Mining

With the advancing of working face,the deformation of overburden,caving and underlying rock movement and expansion will be caused by coal seam mining,which damages the original stress equilibrium around the mining space,and leads to the stress redistribution.Different stress and strain fields was generated in the roof and floor,which produces different damage to the roof and floor rock,and generates different pressure relief effects to protective layer.A simulation research on coal seam group mining is carried out to obtain the laws of stress change and deformation of overlying and underlying rock by the FLAC^3D software.