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.

Clay is a notoriously challenging material to dredge. Due to its adhesion and plastic behaviour, it may clog the suction head and clay balls could form down the pipe line. This will raise difficulties in estimating the production or the required power and increase the risk of downtime. As this is an expensive risk for the dredging industry, there is a lot of literature on the cutting of clay in dredging. However it is focused on the forces and stress distribution near the blade tip. Unfortunately, there is little information on the influence of adhesion and plasticity of clay on the deformation and the sliding of the chip over the tool and their contribution to the total cutting forces. Current models are likely to lack some key details of clay behaviour.
In this review, published results from experiments of cutting in clay have been aggregated. An attempt has been made to evaluate the results uniformly with dimensionless parameters derived by the Buckingham-pi method. The state of the art of models for cutting highly plastic materials is presented, providing a more detailed description of the excavation processes in submerged clay. The test results have been compared with the those existing models. This provides insights regarding chip formation and the deformation of the chip as it moves along the tool. This knowledge provides a basis for solutions needed to avoid clogging of equipment and the occurrence of clay balls.
This review is part of the CHiPS project, which investigates rapid large plastic deformations in submerged clay for Cutting Highly Plastic Soils.