Study on surface movement and deformation laws in miningunder thick water-bearing loose layer

There are certain particularities in the movement and deformation law of the mining surface under the complex geological mining conditions of the extremely thick water-bearing loose layer. In order to study the surface movement and deformation laws of mining under extremely thick water-bearing loose layer,and clarify the influence of the extremely thick water-bearing loose layer on the surface movement and deformation,the Heze mining area was used as the research area,and based on the analysis of the measured data of surface movement and deformation of No.1308 working face in Guotun coal mine,the FLAC3D numerical simulation software was used,and the fluid-solid coupling calculation simulated the surface movement under the thick water-bearing loose layer. The dynamic consolidation settlement scheme,non aquifer scheme and aquifer location scheme were separately formulated. The proportion of seepage consolidation settlement in the thick water-bearing loose layer was calculated quantitatively. The dynamic laws of seepage consolidation settlement of the thick water-bearing loose layer were summarized,comparative analysis of the difference in surface movement and deformation of coal seam mining with or without aquifers,the influence of the position of the aquifer in the loose layer on the movement and deformation of the surface was studied. The research results show that the seepage consolidation settlement caused by mining under the mining conditions of the extremely thick water-bearing loose layer in Guotun coal mine accounts for 8.5% of the total surface subsidence; With the advance of the working face,the changes of excavation deformation and seepage consolidation settlement increment can be divided into three stages:synchronous growth period,dynamic change period and synchronous slowdown period. The hydrophobic seepage and consolidation phenomenon of the aquifer in the thick loose layer affected by mining will cause the increase of surface movement deformation and the expansion of the influence range of surface movement,but the reduction of the maximum curvature and the maximum horizontal deformation indicates the overall shape of the subsidence basin more gentle. There is a correlation between the surface deformation parameters and the position of the aquifer in the thick loose layer,through correlation analysis,the relationship model between the surface movement deformation parameters and the position of the aquifer in the loose layer is established.