Samenvatting

The aim of this thesis is to assess the reliability and accuracy of Miedema's clay-cutting model by critically examining its underlying assumptions and investigating potential discrepancies. The research questions revolve around identifying the inconsistencies in nomenclature, evaluating the chosen strain rate value, assessing adjustments made to shear rate formulation, exploring the relationship between shear angle and the strengthening factor, and lastly investigating a suitable design for a cutting rig for studying clay's mechanical properties. To address these research questions, a comprehensive methodology has been employed. The study begins with a critical analysis of Miedema's model, comparing it with the findings of Hatamura and Chijiiwa to identify discrepancies in nomenclature and clarify definitions. Next, data from Hatamura and Chijiiwa's experiments are used to calculate strain and strain rate, providing insights into the accuracy of Miedema's chosen strain rate value.
The findings of this comparative study ultimately aim to contribute to the development of more accurate cutting models for the dredging sector. As a result, the thesis enhances the reliability of Miedema's clay-cutting model. The insights gained from this research have implications for the broader understanding of clay-cutting processes in dredging.

The primary objective of this study is to evaluate the accuracy of Miedema's model for clay cutting. The results reveal several critical issues and discrepancies within Miedema's theory. The nomenclature used by Miedema lacks clarity and deviates from the definitions provided by Hatamura and Chijiiwa. The assumption of a constant strain rate of 0.03 1/s, derived from Hatamura and Chijiiwa, is found to be inaccurate. Instead, the calculated strain rate values align with those reported by the Japanese researchers, indicating a need for reassessment.
Furthermore, the study highlights the contrasting definitions of the strengthening factor between Wismer and Luth's original formulation and Miedema's modified expression. The calculated values deviate significantly, indicating the necessity for a comprehensive reevaluation of the calculation of the strengthening factor and its relationship to the strain rate in clay cutting models. Moreover, the investigation reveals that the shear angle significantly influences the strengthening factor, contrary to Miedema's assertion of limited dependence. Modifying the shear angle results in corresponding changes in the strengthening factor, emphasizing the importance of considering the shear angle in clay cutting models.
In conclusion, this study exposes limitations and discrepancies within Miedema's cutting theory for clay. The assumptions of constant values, unclear nomenclature, and inconsistencies in strain rate and strengthening factor calculations undermine the accuracy of the model. These findings call for further research and refinement of Miedema's theory, considering specific clay characteristics and behaviors, to develop more accurate and reliable clay-cutting models.