基于格子Boltzmann理论的弱胶结裂隙岩体水沙两相流特性

Characteristics of water sediment two phase flows in weakly cemented fractured rock mass based on Lattice Boltzmann method

通过格子Boltzmann方法对裂隙岩体水沙两相流动规律进行理论分析,建立裂隙岩体水沙两相流动的格子Boltzmann模型,推导了水沙两相的基本守恒方程并建立了水沙两相流动系统的控制方程,基于浸入边界法,利用欧拉点和拉格朗日点处理水沙两相界面。通过数值模拟裂隙溃沙情况,分析了沙粒进入裂隙前后的流动形态,研究了颗粒粒径和裂隙宽度对溃沙速度的影响。借助单裂隙下的研究结果,建立上覆厚松散沙层矿井开采模型,分析裂隙发育下突水溃沙情况,发现在初始阶段,沙粒的溃入会堵塞裂隙,抑制裂隙的发育;随着水压的持续施加,大量水沙混合物开始涌入裂隙,岩体孔隙压力增大,导致裂隙迅速发育扩展,甚至会造成顶板垮落,加剧突水溃沙灾害。

Theoretical analysis is taken on the water sediment two phase flows pattern of fractured rock based on lattice Bohzmann method and a model is built. Also, 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 the immersed boundary method. Numerical simulation is taken on sand inrush, and the flow patterns of sand moving in fracture is analyzed, the influence of particle size and fracture width on the velocity of sand inrush is studied. With the results in single fracture, a mechanical model of sand mining roof covered with thick loose is established to analyze wa- ter and sand inrush, the authors find that at the initial stage, the sand particles flowing in cracks can restrain its devel- opment, with the water pressure continually applied, a large number of water and sand mixture begin 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.