Study on Compaction Characteristics of Paste Filling and Its Application

The load-bearing capacity and deformation response of paste material under uniaxial compression are numerically and experimentally investigated, aiming to shed light on the pressure bearing performance of paste material while controlling ground subsidence after coal extraction. Through the establishment of mathematical models to analyze the influence of different materials on paste properties. The results of numerical simulation and regression equation show that the interaction of components in filling material is the key factor which influences the pressure performance of the filling body. Furthermore, the influence of fly ash on the properties of paste material is larger than that of coal gangue. A uniaxial compression experiment was carried out for the optimum composition ratio of paste material. The experimental results show that the maximum compressive strength of the filling body reaches 21MPa at 30days, since then, although the strength decreases with the increase of time, it is still sufficient to support the overlying strata. Finally, the filling test was carried out at the site. The results show that the average strength of the filling body after filling is 5.9MPa, and the filling effect was good, and the overlying strata were well controlled.