Analysis of the Mechanism of Soil Cutting : 2nd Report. Deformation and Internal Stress of Soil in Cutting

抄録

Deformation and distribution of internal stresses in soil cutting are analyzed by experiment. The variable parameters are kinds of soils (dry quartz sand and plastic loam) and cutting conditions (cutting angle, cutting depth of cut and cutting speed). Sand always shows shear type of chip, and loam generally shows flow type. In both kinds of soils, a flat shear-plane appears. And the angle of shear-plane is smaller as the cutting angle increases. The distribution of internal stresses in soil is measured by internal stress cells. Its idealized pattern is as follows. The maximum principal stress trajectories (compressive) issue in parallel from the surface of cutting blade. Only the trajectories which issue from the cutting edge diverge abruptly. The minimum principal stress in front and lower parts of cutting edge is negative (tensile) under certain circumstances. Many kinds of cutting phenomena and important things for earth-moving machines are explanied from the conception of internal stress.