The Delft Sand, Clay & Rock Cutting Model, 2019a

A Wedge in Clay Cutting.
L3 L7
N3 cos N2 cos
L4 2
L4
L5
C2 sin C3 sin
2
L4
(13-27)
Now N3 can be expressed in a number of known variables according to:
N
3
L7
L5
N2 cos C2 sin
2
L4 2
L4
L3
cos
L4
C3
sin
L3
cos
L4
(13-28)
Substituting equation (13-28) in equation (13-11) gives a solution for the normal force N4.
N C sin N cos C sin N cos
(13-29)
4 2 2 3 3
Substituting equation (13-28) in equation (13-14) gives a solution for the mobilized adhesion Am.
A C cos N sin C cos N sin
(13-30)
m 2 2 3 3
This results in a horizontal force of:
(13-31)
F N sin A cos
h 4 m
And in a vertical force of:
(13-32)
F N cos A sin
v 4 m
Based on the experience with sand cutting it is assumed that the wedge angle θ can be determined by assuming
that the horizontal force should be at a minimum for the angle chosen. It is very well possible that the mobilized
adhesion is negative for large blade angles.
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