This paper provides a new insight into the surveying strategies that are used (or can be potentially used) in ports and waterways with fluid mud layers. The combination of acoustic methods with other methods, which are based on the density or on the shear strength measurements, is discussed. In particular, the measurements by the DensX, the Rheotune, the Graviprobe and the Rheocable are presented Due to the complexity of mud, the strength of mud exhibits a non-linear relationship with the density due to the thixotropic behaviour (deformation, history and time dependence). Therefore, sampling and measuring procedures, followed by data processing and interpretation of the measurements, have to be standardized by means of recognized practical protocols. In-situ measuring tools are available for characterizing the behaviour of fluid mud. Based on our observations, we can conclude that the new surveying strategies can be potentially developed in the ports and waterways with fluid mud layers.@en

This paper gives an overview of the research that has been conducted to get a better understanding of the navigation in ports and waterways with fluid mud layers. In particular, the up-to-date review of reported full scale experiments that involve real vessels is provided. To study physical processes, the full scale experiments are accompanied by scaled experiments and numerical modelling. This combination provides a valuable insight into ship behavior with respect to different navigation conditions and physical properties of fluid mud. Another aspect of this paper are the surveying methods that can localize the fluid mud layers and potentially provide information about the strength of these layers. Some of these methods were tested on fluid mud produced by water injection dredging in the Port of Rotterdam. It was concluded that the new rheology-based method show a potential for understanding of strength development in fluid mud layers. Finally, some open research questions with respect to the applicability of the navigation through fluid mud are discussed.@en

The objective of this study is to get a new insight into in-situ characterization of fluid mud layers. Water Injection Dredging has been performed to create a fluid mud layer in the 8th Petroleumhaven at the Port of Rotterdam. Four measuring tools, conventional multi-beam echo-sounder, DensX, Graviprobe and Rheocable have been used to monitor the fluid mud layer properties over the time. The results suggest that the currently employed density-based nautical depth criterion has to be revised to ensure more efficient navigation in the vicinity of fluid mud layers@en