Evaluation and analysis of metal mine filling based on numerical simulation and actual measurement

In order to make a reasonable evaluation of the effect of backfill mining on non-coal mines, the first phase of the Laixin iron ore mine project is taken as an example. First, a geomechanical model of iron ore mining was established according to geological theory; second, numerical simulation software FLAC3D was used to analyze the surface subsidence, horizontal displacement, plastic failure range of the surrounding rocks, and stress conditions of the surface and surrounding rocks under unfilled and filled conditions; finally, the observation data of surface subsidence in the open area were analyzed against the background of the Phase I mining project of Laixin iron ore mine. The results show that: (1) the amount of surface subsidence increases with the increase of burial depth. As the mining depth increases, the amount of ground subsidence gradually increases. (2) Numerical simulation of the amount of surface subsidence and horizontal displacement in the unfilled condition is ten times that in the filled condition; the plastic zone of destruction in the unfilled condition extends to the surface, and the plastic destruction in the filled condition is mainly in the vicinity of the mining location, and the vertical stress in the unfilled condition is much larger than that in the filled condition; (3) the on-site measured results are basically consistent with the numerical simulation results, and the numerical simulation can be used to reasonably predict the amount of subsidence and horizontal displacement of the ground surface, and the force on the goaf.