This thesis investigates the physics of clay cutting, focusing on the challenges and complexities associated with mechanical excavation. The use of clay is inevitable as a sand replacement in the future. Clay is a fine grained soil with a dense structure that makes it relatively impermeable to water. It can act as a barrier which is beneficial in rivers. Clay can also obstruct constructions, so excavation is needed. By analyzing existing literature and
conducting extensive experiments, the study aims to shed light on the underlying mechanisms governing clay deformation and forces in linear cutting processes. Experiments are conducted using clay with a cohesion of 35 kPa and 60 kPa, while an adhesion ranging from 1.2 kPa to 12.5 kPa. For all parameters of the clay a test is conducted. Direct shear tests for cohesion, adhesion, internal and external friction angles. Tensile testing for the tensile strength of the clay. Cutting tests are conducted on clay with varying parameters, including cohesion, adhesion, cutting depth, blade length, blade angle, and cutting velocity.

The study identifies two primary cutting regimes: flow and curling. While other regimes are theoretically possible, they were not observed in the experiments. The other two regimes: shear and tear could be encounter when sand or silt is added to the clay. The main cutting force and the thrust force are made dimensionless in the analyse. The analysis revealed the relationship between the tested parameter and the cutting forces, highlighting its importance in the overall process. In the end a new model is presented for calculating the main cutting force and the thrust force. A key difference from existing literature is the use of the shear angle and the strengthening factor. The shear angle represents the inclination of the shear plane during clay deformation, while the strengthening factor quantifies the strain rate dependent increase in clay strength under faster deformation conditions. While the shear angle is generally overestimated, the strengthening factor is inaccurately applied. The main cutting force is primarily influenced by cohesion, shear angle, cutting depth and cutting velocity. In contrast, the thrust force is primarily affected by adhesion, external friction, cohesion, cutting depth, and blade angle.

Recommendations for further research include, exploring conditions that could lead to tear or shear failure in clay. The relationship between blade angle and cutting force for linear and non linear cutting. The non linear cutting is especially important in the field. While the experiments in this thesis involved linear cutting, field conditions involve circular blade movements with varying blade angles and cutting depths during the cutting process. This is attributable to the inherent characteristics of cutter suction dredgers. The strengthening factor should also be investigated for other types of clay.