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

The Delft Sand, Clay & Rock Cutting Model.
vc
sin( )
1.4
0 h i sin( )
s
1 ln1
y
0
0 y
0
With : / 0.1428 and 0.03
(7-53)
The shear angle β is determined by the case where the horizontal cutting force Fh is at a minimum, based on the
minimum energy principle (omitting the strengthening factor λs).
2
Fh
2 r sin cos sin sin
2 2 2
sin sin sin
2 2
sin sin 2 sin r sin
2 2 2
sin sin sin
0
(7-54)
In the special case where there is no adhesion a=0, r=0, the shear angle β is:
sin 2
0 for 2 giving = (7-55)
2 2
An approximation equation for β based on curve fitting on equation (7-54) for the range 0.5