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

Figures & Tables.
Figure 5-20: The total cutting force versus the blade angle. ................................................................................120
Figure 5-21: The direction of the total cutting force versus the blade angle. .......................................................120
Figure 5-22: Cutting forces versus cutting velocity. ............................................................................................121
Figure 5-23: A bulldozer pushing sand (commons.wikimedia.org). ....................................................................122
Figure 6-1: The cutting process definitions. .........................................................................................................123
Figure 6-2: The cutting mechanism in water saturated sand, the Shear Type. .....................................................126
Figure 6-3: Water saturated sand modeled according to the Flow Type. .............................................................126
Figure 6-4: The forces on the layer cut in water saturated sand. ..........................................................................127
Figure 6-5: The forces on the blade in water saturated sand. ...............................................................................127
Figure 6-6: The forces on the blade when cutting water saturated sand. .............................................................128
Figure 6-7: The cutting process modeled as a continuous process. ......................................................................129
Figure 6-8: The volume balance over the shear zone. ..........................................................................................131
Figure 6-9: Flow of the pore water to the shear zone. ..........................................................................................132
Figure 6-10: The coarse mesh as applied in the pore pressure calculations. ........................................................133
Figure 6-11: The fine mesh as applied in the pore pressure calculations. ............................................................133
Figure 6-12: The water under-pressures distribution in the sand package around the blade. ..............................134
Figure 6-13: The pore pressure distribution on the blade A-C and in the shear zone A-B. ................................134
Figure 6-14: The equipotential lines. ...................................................................................................................135
Figure 6-15: The equipotential lines in color. ......................................................................................................135
Figure 6-16: Flow lines or stream function. .........................................................................................................136
Figure 6-17: The stream function in colors. .........................................................................................................136
Figure 6-18: The water pore pressures on the blade as function of the length of the wear section w. .................137
Figure 6-19: The water pore pressure in the shear zone as function of the length of the wear section w. ...........137
Figure 6-20: The flow lines used in the analytical method. .................................................................................138
Figure 6-21: A small program to determine the pore pressures. ..........................................................................143
Figure 6-22: The dimensionless pressures on the blade and the shear plane, α=60°, β=20°, k i/k max=0.25, h i/h b=1/3.
.......................................................................................................................................................143
Figure 6-23: The dimensionless pressures on the blade and the shear plane, α=60°, β=20°, k i/k max=0.25, h i/h b=1/2.
.......................................................................................................................................................144
Figure 6-24: The dimensionless pressures on the blade and the shear plane, α=60°, β=20°, k i/k max=0.25, h i/h b=1/1.
.......................................................................................................................................................144
Figure 6-25: The forces F h and F t as function of the shear angle β and the blade angle . .................................146
Figure 6-26: The force F h as function of the ratio between k i and k max. ..............................................................149
Figure 6-27: The reciprocal of the force F h as function of the ratio between k i and k max. ...................................149
Figure 6-28: Friction angle versus SPT value (Lambe & Whitman (1979), page 148) and Miedema (1995)). ..153
Figure 6-29: SPT values versus relative density (Lambe & Whitman (1979), page 78) and Miedema (1995)). 155
Figure 6-30: SPT values reduced to 10m water depth. ........................................................................................155
Figure 6-31: Specific energy versus SPT value (45 deg. blade). .........................................................................156
Figure 6-32: Production per 100kW versus SPT value (45 deg. blade). ..............................................................156
Figure 6-33: The total dimensionless cutting force c t, d t. .....................................................................................159
Figure 6-34: The influence of wear. .....................................................................................................................159
Figure 6-35: The influence of side effects............................................................................................................159
Figure 6-36: Side view of the old laboratory. ......................................................................................................161
Figure 6-37: The cross section of the new laboratory DE. ...................................................................................162
Figure 6-38: An overview of the old laboratory DE. ...........................................................................................162
Figure 6-39: An overview of the new laboratory DE. ..........................................................................................163
Figure 6-40: A side view of the carriage. .............................................................................................................164
Figure 6-41: The construction in which the blades are mounted..........................................................................164
Figure 6-42: The blades are mounted in a frame with force and torque transducers............................................165
Figure 6-43: The center blade and the side blades, with the pore pressure transducers in the center blade. ........165
Figure 6-44: A blade mounted under the carriage in the new laboratory DE. ......................................................166
Figure 6-45: The center blade of 30º, 45º and 60º, with and without wear flat. ...................................................167
Figure 6-46: Measuring the cone resistance of the sand. .....................................................................................167
Figure 6-47: The pre-amplifiers and filters on the carriage. .................................................................................168
Figure 6-48: A view of the measurement cabin. ..................................................................................................169
Figure 6-49: The development of cavitation over the blade. ................................................................................178
Figure 6-50: Partial cavitation limited by dissolved air, α=45º, h i=7cm. .............................................................179
Figure 6-51: The forces from which the soil/steel friction angle δ can be determined. .......................................180
Figure 6-52: The forces from which the angle of internal friction φ of the sand can be determined. .................180
Figure 6-53: The location of the pressure transducer behind the blade. ...............................................................181
Copyright © Dr.ir. S.A. Miedema TOC Page 437 of 454