高密度悬移质沉积物下水下地形测量研究

Research on Underwater Topography Survey under High Density Suspended Sediment

水下地形测量时遇到高密度悬移质沉积物的水域,单频测深仪声波信号被沉积物或污泥吸收而消失,测深数据无法采集.尤其在近海动态的海域测量,淤泥深可陷至膝盖的海滩,常规的方法是利用测船借涨潮之机来获取断面线上滩涂数据然而潮水冲击淤泥使高密度悬移质增厚,导致测深仪无法获取测深数据,又不能及时进行补测.例如:在钱塘江杭州湾南岸的曹娥江口门、余姚新陶家路闸、慈溪等滩涂上断面测量°本文提出了一种针对性的解决思路,并在相对静态的湖漫水库,按照设置的重叠带对相同河床底质进行不同仪器、不同频率的测深试验,选择几种计算方法来互查互检,对不同仪器不同方法获得的数据进行分析比对,均取得成功,从而实现高密度悬移质沉积物下的水下地形测量。

When underwater topographic survey encounters the waters with high density suspended sediment, the acoustic signal of single frequency bathymeter is absorbed by the sediment, thus the bathymetric data cannot be collected. Especially in the offshore dynamic waters, mud on the beach can rise to the knee. The conventional method is to use the ship to obtain the tidal flat data on the section line through the flood tide. However, tidal impacting mud thickens high-density suspended sediment, which makes bathymeter unable to obtain bathymetric data and make supplementary measurement in time. Cross-section measurements that made on the tidal flats of Cao'e River Estuary Gate, new Taojialu Gate in Yuyao and Cixi on the south bank of Hangzhou Bay in Qiantang River, were all the same case. This paper puts forward specific solutions. In the relatively static Humai Reservoir, different instruments and different frequency sounding tests are carried out on the same riverbed sediment according to the set overlapping area. Several calculation methods are selected for mutual inspection, and the data obtained by different instruments and methods are analyzed and compared. It is proved to be correct and reliable, thus realizing underwater topographic survey under high density suspended sediment.