Research On The Deformation Rule Of Surface Movement Caused By Mining Under The Conditions Of Thick Alluvium And Hard Solid Rock

Mining row in Shaanxi Binchang mine is the coal-bearing seam of the Lower Jurassic Yanan Formation. Its surface covers with 60 to 140m thick layer of loess and the topography is the broken loess plateau with gully landforms. The overlying strata integrated lithology of the row is the medium hard rock, especially the Lower Cretaceous Luohe Formation (K1l), the Lower Cretaceous Yijun Formation (K1y), clay sandstone formation of Anding Formation seam 6 is in great thickness, high strength and hard lithology. It plays a role in controlling overlying rock damage under the conditions of certain mining scope. Therefore, under the mining of thick alluvium and thick hard rock, the study on the movement and deformation of the surface and the structure stability of overlying rock is of great significance to the production safety of Shaanxi Binchang mine.Founded on the feasibility study for protection to ground building of row exploitation of first mining working face 40301 in Binchang mining-Great Buddhist Temple and based on spot investigation and observation data, this paper analyzes features of subsidence damage affected by mining action under the conditions of thick alluvium and hard solid rock, combining the characters of thick layer of loess in physical mechanics. After applying cover rock supporting plate theory, the damage patterns and intensity and stiffness damage criteria are calculated and analyzed under the condition of thick alluvium and hard solid rock. According to the structural stability of hard rock supporting plate in the overlying strata of the coal seams, characters of the loess deformation and damage and the influence of the hard rock on the rock movement parameters, expected correction model through probability integration is given under this special condition, combined with similar material simulation experiments, numerical analysis, and field observation data. Then the characteristics of surface subsidence under the condition of thick alluvium and thick hard rock are analyzed with engineering instances, which provide a theoretical basis for the production safety of the mine.