浮泥发育时双频回声测深误差及其对适航水深监测的影响

基于Odem Echotrac MKIII双频测深仪现场测深记录和同步Stema Densitune音叉密度计现场测量结果探讨了浮泥发育时双频回声测深误差及其对适航水深监测的影响。结果表明:1)初始发育阶段非典型浮泥工况下,双频测深仪的高频数字化水深有可能包含少部分上层浮泥层厚度,而低频数字化水深则可代表硬底床位置,高低频水深差明显小于浮泥层厚度;2)发育阶段典型浮泥工况下,双频测深仪的高频数字化水深代表浮泥上层位置,而低频数字化水深则可能未到达硬底床位置,高低频水深差≤浮泥层厚度;3)固结消亡阶段浮泥工况下,双频测深仪的高频数字化水深代表浮泥上层位置,而低频数字化水深则位于靠近浮泥层上边界的密度梯度突变位置,高低频水深差明显小于浮泥层厚度;4)在浮泥固结消亡阶段以及少部分充分发育阶段,简单地采用双频回声测深仪测深结果来快速确定航道适航水深会造成实际适航水深利用程度下降。

Measurement error of dual-frequency echosounder and its influence on navigable depth survey during fluid mud period

The measurement error of dual-frequency echosounder and its influence on navigable depth survey during period of fluid mud is discussed based on the field measured data obtained by Odem EchotracMKIII echosounder and Stema Densitune meter. The results are as follows: 1) High-frequency echosounder record may include part of the fluid mud layer and low-frequency echosounder record equivalent to the consolidated bed under the situation of initial stage fluid mud. 2) High-frequency echosounder record equivalent to the upper limit of the fluid mud and low-frequency echosounder record may locate in the fluid mud layer which is higher than the consolidated bed under the situation of typical fluid mud. 3) High-frequency echosounder record equivalent to the upper limit of the fluid mud and low-frequency echosounder record mostly locate at the fluid mud density mutation which is nearest the upper limit of the fluid mud under the situation of consolidating stage fluid mud. 4)Low-frequency echosounder record is no larger than the navigable depth while fluid mud exists in the navigation channel under the situation of consolidating stage fluid mud or sometimes existence of typical fluid mud, which may waste part of the real navigable depth.