Experimental Study on Deformation Characteristics of Gangue Backfill Zone under the Condition of Natural Water in Deep Mines

To address the problem of surface subsidence caused by the compression of filling gangue in deep mines, a layered compaction test was designed based on the zonation of the failure of the overburden in the goaf and layered property of the filling gangue. The deformation characteristics of filling gangue in natural and water-bearing states were obtained. The deformation of filling gangue during the 0 similar to 100 kN loading stage was an approximately positive S-type, which reflects the relative "advancement" in terms of deformation. The filling gangue deformation in the 100 similar to 500 kN loading stage was an approximately inverted S-type, which reflects the relative "lag" in terms of deformation. In a natural state, the load-time curves of the dead load stage were consistent. Under a water-bearing condition, the load-time curve for the dead load stage had apparent "step" characteristics and presented a special phenomenon of displacement rebound. Under gradient loading, the strain showed an exponential growth model, and energy dissipation showed a logarithmic growth model. Under a natural state, the energy dissipation showed consistently increasing distribution patterns, while the energy dissipation showed a normal distribution model under the water-bearing state.