The wedge mechanism for cutting of water saturated sand at large cutting angles
Type:
Presented during:
WODCON XVII: "Dredging in a Sensitive Environment" - 2004, Hamburg, Germany
Authors:
Dr. ir. S.A. Miedema, Ir. D.D.J. Frijters
Abstract: The paper describes the results of the theoretical and experimental research of the cutting of water saturated sand at large cutting angles. Therefore cutting tests are carried out at blade angles of 60º, 75º and 90º, which are visually recorded. While the existing cutting theory of Miedema predicts infinite or negative cutting forces at large cutting angles, research is carried out to identify the failure mechanism while cutting at these angles. During these tests a wedge is observed at blade angles higher then 75º. This wedge is dynamic.
Dynamics of the wedge consists of a stationary velocity profile within the wedge, which varies from a maximum velocity at the top side of the wedge, to a lower velocity along the blade surface. Blade angles between 45º and 75º form a transition region for the failure mechanism. Based on the cutting tests a theoretical model was constructed. This was implemented in a calculation model in Visual Basic, with which a prediction for the existence of a wedge can be given for various soils. With the theoretical model the velocity and deformation profile can be described.
Keywords: cutting of sand, kinematic wedge, soil failure mechanism