From the performed research the following general conclusions can be drawn:
Both the measured cutting forces as the measured water sub-pressures agree reasonably with the theory. For both sand types is observed that the cutting forces and the water sub-pressures become smaller in comparison with the theory, when the blade angle becomes larger. For the 30o blade the cutting forces and the water sub- pressures are larger or equal to theoretical derived values, while for the 60o blade the theory can overestimate the measurements with a factor 1.6. This can be explained by assuming that with an increasing blade angle the cutting process becomes more discontinuous and therefore decreases the average volume strain rate. Slices of sand shear off with dilatancy around the shear planes, while the dilatancy is less in the sand between the shear planes. The theory can still be pretty useful since in dredging practice the used blade angles are between 30o and 45o.
Side effects can considerably influence the direction of the cutting forces, although the magnitude of the cutting forces is less disturbed. As a result of the side effects the cutting forces are aimed more downward.
Wear effects can also influence the direction of the cutting forces considerably, while also the magnitude of the cutting forces is less disturbed. As a result of the wear the cutting forces are, however, aimed more upwards.