TY - JOUR
T1 - Rheological analysis and rheological modelling of mud sediments
T2 - What is the best protocol for maintenance of ports and waterways?
AU - Shakeel, A.
AU - Kirichek, Alex
AU - Talmon, A.M.
AU - Chassagne, C.
PY - 2021
Y1 - 2021
N2 - Natural mud sediments display complex rheological behaviour like thixotropy, viscoelasticity and yield stress. These rheological characteristics can significantly vary over depth, from one mud layer to another, as each layer can have a different density and composition. Fast and reliable measurements of yield stresses of mud samples are important for maintenance operations in ports and waterways. These protocols, performed in the laboratory, should give a rheological fingerprint which is representative of the in-situ behaviour of the mud. In this article, we show that our recently developed stress ramp-up rheological protocol is a time-efficient and well-grounded protocol to determine the yield stresses of natural mud samples by comparing with other existing well-grounded protocols. In this study, we also refine the stress ramp-up protocol such as to reduce the experimental time for different mud layers based on their densities. The protocol was tested on a large number of mud samples obtained from different locations/depths of the Port of Hamburg, Germany. An empirical model is proposed to fit the two-step yielding behaviour that the mud samples exhibit. The model captures the two-step yielding phenomenon in mud samples quite well, within the density range of 1050–1200 kg. m−3. This two-step yielding is a feature of mud samples as found in various harbours and estuaries worldwide in rheometry.
AB - Natural mud sediments display complex rheological behaviour like thixotropy, viscoelasticity and yield stress. These rheological characteristics can significantly vary over depth, from one mud layer to another, as each layer can have a different density and composition. Fast and reliable measurements of yield stresses of mud samples are important for maintenance operations in ports and waterways. These protocols, performed in the laboratory, should give a rheological fingerprint which is representative of the in-situ behaviour of the mud. In this article, we show that our recently developed stress ramp-up rheological protocol is a time-efficient and well-grounded protocol to determine the yield stresses of natural mud samples by comparing with other existing well-grounded protocols. In this study, we also refine the stress ramp-up protocol such as to reduce the experimental time for different mud layers based on their densities. The protocol was tested on a large number of mud samples obtained from different locations/depths of the Port of Hamburg, Germany. An empirical model is proposed to fit the two-step yielding behaviour that the mud samples exhibit. The model captures the two-step yielding phenomenon in mud samples quite well, within the density range of 1050–1200 kg. m−3. This two-step yielding is a feature of mud samples as found in various harbours and estuaries worldwide in rheometry.
KW - Natural mud
KW - Yield stress
KW - Rheological protocol
KW - Flow curve
KW - Empirical models
UR - http://www.scopus.com/inward/record.url?scp=85106382844&partnerID=8YFLogxK
U2 - 10.1016/j.ecss.2021.107407
DO - 10.1016/j.ecss.2021.107407
M3 - Article
SN - 0272-7714
VL - 257
SP - 1
EP - 10
JO - Estuarine, Coastal and Shelf Science
JF - Estuarine, Coastal and Shelf Science
M1 - 107407
ER -