黄河三角洲沉积物侵蚀再悬浮动力机制研究

在黄河三角洲沉积动力学研究中,波浪与海流是海底沉积物再悬浮的主要动力因素, 两个动力因素如何影响沉积物侵蚀再悬浮,亟待深入研究。笔者应用自制屏蔽波浪或海流实验箱在现代黄河三角洲地区开展观测研究,结果表明:(1)在屏蔽波浪的条件下,当该研究区域风浪小及海水流速小于15 cm·s^-1时,海底沉积物不发生侵蚀再悬浮,海水浊度小于30NTU;当该研究区域风浪大及海水流速在15-40 cm·s^-1之间时,海水浊度一般在100NTU-500NTU之间。(2)在屏蔽海流的条件下,海水浊度随有效波高增大而增大,波浪对沉积物再悬浮贡献率为14%~73%。(3)在波致沉积物再悬浮过程中,波浪“泵送”作用对沉积物再悬浮贡献为11.5%~42.8%,波浪剪切作用对沉积物再悬浮贡献为57.2%~88.5%。

Dynamic Mechanism of Sediment Resuspension in Yellow River Delta

In the sedimentary dynamics study of Yellow River Delta, the waves and the currents are the main motivation factors of seabed sediment resuspension. But how the factors affect sediment resuspension needs in-depth study. We carried out observational study using homemade experimental box shielded by waves or currents in the modern Yellow River Delta. The results show that:(1) Under the conditions of the wave shield, when the stormy waves is smaller and the water flow rate is less than 15 cm·s^-1, the sediment resuspension does not occur, the seawater turbidity is generally less than 30NTU. When the stormy waves is bigger and the water flow rate is between 15 cm·s^-1 and 40 cm·s^-1, the seawater turbidity generally is ranged from 100NTU to 500NTU.(2) Under the conditions of the current shield, the seawater turbidity increases with the significant wave height increases, the contribution rate of waves on sediment resuspension is 14%~73%.(3) In the wave-induced sediment resuspension process, the contribution rate of wave "pumping" effect on sediment resuspension is 11.5%~42.8%, the contribution rate of shearing action of wave on sediment resuspension is 57.2%~88.5%.