埕岛海域浅水区人工构筑物周边海底地形演化与海洋灾害地质现象关系研究

Seabed Evolution around Artificial Works in the Chengdao Shallow Water Area and Its Relations to Subbottom Hazard

高分辨率的回声测深、旁侧声纳及3.5 kHz浅地层剖面的探测发现:埕岛海域浅水底坡人工构筑物周边沉积物块体运动极为发育。这种使局部浅水区浅层沉积物向深水洼地填充的沉积物再搬运营力,大大减缓了埕岛海域浅水区人工构筑物周围水力冲刷凹坑的水深增大幅度,而凹坑边缘区域在沉积物块体运动、海洋水动力侵蚀和底床固结沉降的共同作用下,水深平均增加幅度高达0.4 m/a,“凹坑”面积逐年扩大,边坡坡度平均每年以5‰减缓。

It is shown from the bathymetric data that the sediment mass movement around the artificial works in the Chengdao shallow water area is greatly developed. The agent to transport the shallow sediment from the shallow water area to the deep water area greatly reduces the increase in water depth in the scour pit around the artificial works in the Chengdao shallow water area, and the average increase in water depth in the pit edge area is as high as 0. 4 m/a due to the joint actions of sediment mass movement, hydropower erosion and seabed consolidation settlement, so the pit area increased gradually, but the gradient of pit side slope decreased by 5‰ per year on an average.