Numerical Simulation of Surface Subsidence by Solid Backfill Mining

Solid backfill mining is a good green mining technology in recent years,which was applied initially in China with few measured data.This paper studied discipline of differnent solid filling rate and different elastic modulus under different conditions of surface subsidence with FLAC^3D numerical simulation in a pilot coal face.The results showed that,with the filling rate decreased from 100% to 50%,maximum subsidence increased from 312 mm to 907 mm.Filling rate has great impact on subsidence.It is useful to guarantee filling top to prevent surface deformation in the choice of filling mining.With the filling bulk modulus increases from 24 GPa to 0.24 GPa,the maximum value of surface subsidence decreases rapidly.It is very important to choose a reasonable filling size which can meetthe requirement of the deformation resistance.