Water and mud inrush dynamics process simulation by using coarse-grained CFD-DEM method

Water and mud inrush disaster is a typical fluid-solid coupling problem, and its forecasting and prevention can reduce human and economic losses. In this work, a coarse-grained discrete element method and computational fluid dynamics model based on bonded particles is employed to investigate an inrush disaster happened in Foshan Metro Line 2. It's shown that the current model can simulate beam bending, and the differences from the analytical solution are 7% and 5% in deflection and maximum axial stress. This study also suggests that two-way coupling is in superior agreement with field observation than one-way coupling. The water pressure is highly influential as it increases from 0.15 MPa, 0.25 MPa, 0.35 MPa to 0.45 MPa inrush occurrence time varies from 28.0 s, 11.5 s, 7.5 s to 5.0 s, respectively. The current model is capable of simulating water and mud inrush, and may provide a framework for investigating this disaster in complex engineering scenarios. [Display omitted] •Soil-water interaction during water and mud inrush is studied using CG CFD-DEM.•The DEM model based on PBM can simulate the behavior of the continuum media.•One-way coupling presents a slug flow pattern in the tunnel.•Two-way coupling shows an obvious dominant seepage channel.•Water and mud inrush dynamic is sensitive to particle size and water pressure.