6.15: The Snow Plough Effect

Last updated
Save as PDF

Page ID: 34786

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

To check the validity of the above derived theory, research has been carried out in the new laboratory DE. The tests are carried out in hard packed water saturated sand, with a blade of 0.3 m by 0.2 m. The blade had a cutting angle of 45 degrees and inclination angles of 0, 15, 30 and 45 degrees. The layer thicknesses were 2.5, 5 and 10 cm and the drag velocities 0.25, 0.5 and 1 m/s. Figure 6-57 and Figure 6-58 show the results with and without an inclination angle of 45 degrees. The lines in this figure show the theoretical forces. As can be seen, the measured forces match the theoretical forces well. Since the research is still in progress, further publications on this subject will follow.

More results of measurements can be found in Appendix M and Appendix N

Screen Shot 2020-08-20 at 8.24.33 PM.png — Figure 6-54: An example of pore pressure measurements versus the theory.

Screen Shot 2020-08-20 at 8.26.09 PM.png — Figure 6-55: An example of the forces measured versus the theory.

Screen Shot 2020-08-20 at 8.27.40 PM.png — Figure 6-56: An example of the measured signals (forces and pore pressures).

The result of a cutting test graphically. In this figure the horizontal force F_h, the vertical force F_vand the water pore-pressures on the blade P₁, P₂, P₃ and P₄ are shown. The test is performed with a blade angle α of 45^o, a layer thickness h_i of 70 mm and a cutting velocity v_c of 0.68 m/s in the 200 μm sand.

Screen Shot 2020-08-20 at 8.31.54 PM.png — Figure 6-57: F_h, F_v, F_d **and** E_sp **as a function of the cutting velocity and the layer thickness, without deviation.**

Screen Shot 2020-08-20 at 8.33.26 PM.png — Figure 6-58: F_h, F_v, F_d **and** E_sp **as a function of the cutting velocity and the layer thickness, with deviation.**