西沙群岛珊瑚砂运动特性试验研究

珊瑚砂具有颗粒密度较大、孔隙率较高、干密度较小、压缩性较高等物理特性。其形成过程相对短暂,搬运距离有限,珊瑚砂磨圆度较低,颗粒形态差异明显,颗粒之间有效接触面积较小,粘着力较低。这些特性决定了珊瑚砂在动力作用下易于起动搬运的运动特征。文章对西沙群岛珊瑚砂的比重、孔隙率、休止角和渗透性等物理性质以及水流、波浪作用下的起动特性进行了试验测定,试验结果也表明了珊瑚砂起动特性符合目前经验公式计算值。

Study on movement characteristics of coral sands in Xisha Islands

Coral sand has special physical characteristics such as greater grain density,higher porosity,lower dry density and higher compression,etc.The formation process is relatively transient and the transportation distance is finite,so its psephicity is low and the difference of morphology is obvious.The effective contact area between particles is small,and adhesive force is low.Above all,the coral sand is easy to move under the action of wave and current.The specific gravity,porosity,angle of repose,permeability and starting character under the action of current and wave were studied by physical model in this paper.The result shows that movement of coral sands accord with the value calculated by empirical formula.