COMPARISON OF THE GORYACHKIN THEORY TO SOIL FLOW ON A SWEEP

The Goryachkin trihedral wedge theories describe soil flow over a surf ace resembling the wing of a sweep. The current study tested the Gorya chkin crushing and lifting theories' prediction of soil flow across a sweep by comparing with measurements from observed soil flow. Treatmen ts included sweeps with three different rake angles (13.5, 16, and 44- degrees) operated at three speeds (5, 7, and 9 km/h) and at two depths (50 and 100 mm). Flow direction was determined from scratch marks on the sweep surface. In agreement with the Goryachkin theories, observed soil flow changed with rake angle, but not with speed or depth. In a manner opposite of that predicted by the theories, the ratio of vertic al to lateral soil movement increased as rake angle increased. Most pr edicted values were outside of a 99% confidence interval of observed m eans. Soil flows on the sweep did not deviate appreciably (more than 5 -degrees) from a vertical plane parallel to the travel direction. The theories did not adequately predict observed soil flow on a sweep.