A study on Contact Networks between Gravels and Movements of Sands and Gravels

采用室内试验和数值模拟相结合的方法，研究了非对称振荡流作用下砂石的运动规律。非对称振荡流实验表明，当砾石比例大于60%时，由于砾石之间的接触网络，砾石的运动受到很大的抑制。这些实验结果与已建立的振荡流下混合颗粒输沙公式不符。通过离散单元法对颗粒填充的数值模拟，发现当砾石的掺量从40%增加到60%时，砾石之间的三维接触网络急剧发展。研究发现，砂石的运动规律与混合砂的运动规律有很大不同。

The movement of sand and gravels under asymmetric oscillatory flow was studied by laboratory and numerical experiments. The experiment under asymmetric oscillatory flow showed that the movement of gravels was drastically restrained because of the contact network between gravels when the ratio of gravels was over 60%. The result of these experiments did not agree with the established formula of the mixed grain sand transport under oscillatory flow. From numerical simulation of filling up of particles with DEM(Discrete Element Method), it was found that 3D-contact networks between gravels drastically developed while the mixing ratio of gravels increased from 40% to 60%. It was found that the movement of sand and gravels was greatly different from the movement of the mixed sand.