Cutting of highly plastic clay
analysis of large rapid deformation processes
M.O. Winkelman (TU Delft - Offshore and Dredging Engineering, Damen Dredging Equipment)
F.T. Kruis (Student TU Delft, Damen Dredging Equipment)
DL Schott (TU Delft - Transport Engineering and Logistics)
R. Helmons (TU Delft - Offshore and Dredging Engineering)
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Abstract
Clay is a notoriously challenging material to dredge. Due to its adhesion and plastic behaviour, it may clog the suction head and/or clay balls could form in the pipeline. This will raise difficulties in estimating the production, the required power and increase the risk of downtime. As this is an expensive risk for the dredging industry, the cutting process requires in depth research to achieve better understanding of the process, to prevent problems and to mitigate risks. Available literature on clay deformation and soil cutting has been reviewed. Important topics for the cutting process are the interaction between the clay sliding over the blade and the resulting macro deformation of the chip. Various cutting regimes can be distinguished, including the: Flow regime, Tear regime, Curling regime, etc. Additionally the best practices for soil bin experiments have been included. Review of the available literature and analysis of published models is used to design a soil bin experiment dedicated to test the process under conditions relevant for the dredging industry. The objective of the CHiPS project is to study cutting regime transitions for dimensionless parameter groups of soil properties and operating conditions. Transitions range from static traction problems on soft mud to grinding action on stiff clay. Preliminary results and analysis of these clay cutting experiments are presented. The test rig developed for the CHiPS project is functionally performing satisfactorily, but requires a stronger drive to test high-strength soils.