Abstract:To study the deformation characteristics of rock strata under gangue filling in the extra-thick coal seam, the confined compression test was used to study the deformation characteristics under compressive stress by taking gangue as filling material, and the numerical model was established by FLAC3D to compare and analyze the force and deformation of rock strata under the two mining modes of filling and unfilling. The elastic modulus of gangue compacted with 8MPa under lateral compression test is applied to the numerical model. The research results show that the deformation characteristics of gangue filling body show that the strain variable increases gradually with the continuous increase of load, and the two show a logarithmic function relationship. The strain variable changes obviously in the early stage, and gradually decreases in the later stage because the gangue-filling material is compacted. After gangue filling mining, the displacement of rock formation is reduced compared with that without filling, and the distribution of stress in a rock formation is more uniform. Both the test and simulation results show that the compaction of gangue makes the deformation of the filling body tend to be stable, so that it can bear compressive stress.