【作者】 孙其诚； 王光谦；

【Author】 Sun Qicheng, Wang Guangqian (State Key Laboratory for Hydroscience and Engineering, Tsinghua University, Beijing 100084, China)

【机构】 清华大学水沙科学与水利水电工程国家重点实验室；

【摘要】 地震诱发的堰塞湖是松散的土石颗粒沿坡面滑动,而堵截山谷、河谷或河床后贮水形成的湖泊,目前土石颗粒的流动规律尚不能被现有力学理论予以适当描述。作为前期工作,清华大学开展了颗粒沿斜面流动的机理研究工作。基于严格的颗粒接触理论,建立了离散动力学模型,对准三维斜面颗粒流进行了数值模拟。发现随着摩擦系数由零增加到0.85时,颗粒配位数峰值从6减小为4;颗粒层内平均速度随深度而线性增加,同时发现顶部和近底部沙粒层内的速度涨落和颗粒体积分率变化较大。更多还原

【Abstract】 Quake lakes are formed as water was shoved from its bed by rock and mud slides off by the earthquakes. The sliding of rock particles could be treated as granular flow along inclined planes, which is observed fundamentally different from any other type of flows. Common granular flows in nature are dense flow packed with solid fractions above 56% by volume. Inclined plane flows are usually employed to study the mechanics of dense granular flow, due to the accessibility in experiments. In this work, we build a discrete element model(DEM) with Hertzian contact theory and Mindlin-Deresiewicz contact theory. A dimensional flow, i.e. periodic boundaries are employed in all directions except the rough surface plane. 13000 sand grains are used in simulations where the plane surface is taking higher friction coefficient instead of gluing particles along surface. We found that the peak value of coordination number shifts from 6 to 4 as friction coefficient increasing from zero to 0.85. The mean velocity of sand is found proportional to the local position. However, fluctuations in velocity and volume fraction of solids are much greater on layers along surface and near the bottom.更多还原