| Coral sand is form of coral reefs refined in the sea with all kinds of marine power fragmentation, due to moving distance is limited, it distributes around the coral island generally. Today, the marine competition is very fierce in the world, coral island and nearby natural resources is very important. Coral coast is full of coral sand, studying on the motion characteristics of coral sand make a difference to preventing coral island erosing from sea and deducting its evolution process. The sediment motion theory has developed maturely at present, all kinds of unique properties of coral sand make sediment motion research is applicable to coral sand still remains to be seen.This paper collected prototypical coral sand from one coral island of the south China sea, via experimental analysizing, its basic properties is much different from natural quartz sand in morphology, density, porosity, angle of repose etc.Through physical model experiment carried out in the wave flume, have got the incipient wave heigh of three kind coral sand of median diameter and analysized the force of coral sand incipient based on the sediment motion theory, fitted out the experience formula for computing incipient wave height of coral sand. In addition, analysizing incipient shear stress based on linear wave theory, it found that fine particle size of coral sand accord well with those of the original shields curves, coarse that is relatively more difficult to start, finally, the paper introduces the shape coefficient of the coral sand to fit shields curve which can describe the coral sand priming. In numerical simulation, with the aid of FLOW-3D software to establish the numerical flume, using the VOF free surface tracking method to analysize wave propagation and the characteristics of flow field, and solve bottom shear stress under the condition of a given wave tank, its consistent effect is good via comparing the results with that of physical model test verification. |
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