崩破波作用下粉沙悬浮运动特性的试验研究

Experimental study of silt suspension movement under spilling waves

粉沙质海岸在我国沿海广泛分布,由于粉沙运动特性既不同于沙又不同于泥,其易于起动和沉降,在大风天破波作用下水体含沙量急增,常造成港口外航道骤淤,严重影响港口正常运营,造成巨大的经济损失。本文通过室内1%和2%缓坡长水槽试验,初步研究了粉沙在破波作用下悬浮运动特性,分析了破波带内、外粉沙悬浮特性的变化规律,基于拜格诺能量原理,提出了崩破波作用下水体挟沙力计算公式,公式拟合效果较好。研究成果将为粉沙运动特性理论研究、航道泥沙回淤预报以及港口航道工程规划设计等提供一定的参考。

The silty sand coast is widely distributed along the Chinese coastline and it is easy to initiate and to settle down, so its movement character is different to that of sand or mud. Particularly, under breaking waves, the suspended sediment concentration of water body is increased significantly, and the outer channel of the harbor is easy to be silted suddenly. It seriously affects the normal operation of the harbor and the economy loss is very huge. In this study, flume tests on silty sand movement characters were done on 1% and 2% slopes, respectively. Suspension movement rules of silty sand inside and outside the surf zone are analyzed. Based on the Bagnold＇s energy theory, a formula is proposed to compute suspended sediment concentration un- der spilling waves, and the prediction of the formula shows a good agreement with the measured data. The re- search results will provide an important reference for theoretical research on sediment transport, forecast of sediment siltation in the channel, and planning and design of port engineering.