论文部分内容阅读
沉积物颗粒与下覆颗粒间转动角是制约沉积物颗粒起动的一个重要因素。本文样品采集于1987年。作者通过一系列实验探明了沉积物转动角同颗粒形状、相对粒径比以及迭瓦状构造等因素之间的相互关系。在均匀粒径条件下,球状砾石转动角的测量数值同理论数值相吻合,但随粒径的减小而增大。这一结果同前人利用球状砂粒进行实验所获得的结果相一致。利用球状、椭球状及棱角状砾石进行的实验表明,沉积物转动角φ随相对粒径的增大而减小,随颗粒扁平度及颗粒棱角度的增大而增大。扁平砾石的迭瓦状构造将导致转动角的增大,其增大值约等于砾石的迭瓦角。若其它因素相同,沉积物起动的难度自球状、椭球状、棱角状及迭瓦状构造而依次增强。这些结果将有助于对颗粒粒径、形状、构造同沉积物搬运临界状态以及沉积物选择性起动之间的相互关系进行定量分析。
Sediment particles and underlying particles between the rotation angle is restricting the sediment particles start an important factor. This sample was collected in 1987. Through a series of experiments, the authors proved the relationship between sediment rotation angle and particle shape, relative particle size ratio, and lamination structure. Under the condition of uniform particle size, the measured value of spherical gravel rotation angle is in agreement with the theoretical value, but increases with the decrease of particle size. This result is consistent with the results of previous experiments using spherical grit. Experiments using spherical, ellipsoidal and angular gravels show that the rotation angle φ of the sediment decreases with the increase of the relative particle size, and increases with the increase of the particle flatness and the angularity of the particles. The conglomeration of flat gravels will result in an increase of the rotation angle, which increases by about the same as the grazing angle of the gravel. If other factors are the same, the difficulty of starting sediment from the spherical, ellipsoid, angular and Diego-like structure and in turn enhanced. These results will help to quantitatively analyze the correlation between particle size, shape, structure criticality of sediment transport, and selective activation of sediments.