Analysis of Surface Subsidence Laws of Solid Filling Mining Under Buildings

In order to study the influencing factors of surface subsidence in solid filling mining and realize safe mining under the building, this paper analyzes the relationship between surface deformation parameters and backfill compressibility and backfill ratio by taking the T3281N working face of Tangshan Mine as the engineering background and using the combination of field measurement and FLAC^3D numerical simulation. The results show that the maximum sinking value of the measured surface is 38 mm, which only accounts for 1% of the mining height. The surface deformation of the filling mining is small. When the filling rate increases from 70% to 95%, the peak value of the surface subsidence and the horizontal deformation peak are reduced 67.1% and 70%respectively. When the compression ratio is reduced from 25% to 5%, the peak value of surface subsidence and horizontal deformation are reduced by 61.8% and 61.3%, respectively. Reasonable increase of filling rate and compaction can effectively reduce the degree of mining subsidence and fully protect the surface construction.