Experimental study on failure characteristics of strata with differentfilling rates in longwall filling mining

In order to study the mechanical characteristics of overburden failure, according to the geological and mining conditions of a mine working face, the effects of different filling rates on the movement characteristics of overburden were studied by similar simulation test methods. The results show that the severity of overburden deformation is closely related to the filling rate. When the filling rate is low, the distribution of cracks is expanded, and vertical and transverse staggered fissures appear. When the filling rate is high, the fissures only appear in the lower strata, and the overburden is relatively complete as a whole.There is a power function relationship between the influence distance of mining and the filling rate, and the degree of concentrated stress decreases linearly with the increase of filling rate; when the filling rate is low, the vertical displacement of the rock layer is obviously differentiated, and when the filling rate is high, the strata displacement concentration occurs near the immediate roof and the strata. In the direct top and nearby rock formations, the displacement curves of each rock layer are bonded together in the stable subsidence zone, showing the overall bending deformation movement characteristics. Filling rate is an important factor in controlling surface deformation. The research results are of great significance to guide the practice of filling mining.