Characteristics of Water Sediment Two Phase Flows in Weakly Cemented Fractured Rock Mass Based on Lattice Boltzmann Method

Theoretical analysis is taken on water sediment two phase flows pattern of fractured rock based on lattice Boltzmann method and a model is built, the basic conservation equations are derived and the control equations are established. The water and sand phase interface is analyzed by using the Euler point and Lagrange point based on immersed boundary method. Numerical simulation is taken on sand inrush, and the flow patterns of sand moving in crack is analyzed, the influence of particle size and crack width on velocity of sand inrush is studied. With the help of results in single fracture, a mechanical model of sand mining roof covered with thick loose layers is established to analyze water and sand inrush, we can found that in the initial stage, sand particles flowing in cracks can restrain its development, with the water pressure continually applied, a large number of water and sand mixture began to flow in, which makes the pore pressure increase, causing the cracks rapidly develop, even causing the roof fall, aggravating the water and sand inrush. The results can provide theoretical and technical basis for high impact safe mining and environment protection in Western China.