The Influence of Soil Failure Angle on the Performance of a Model ChiselFurrower in a Vertisol

摘要

Design features of a model chisel furrower were subjected to standard soil mechanics equations to compare its performances in terms of draught and soil coefficients with those obtained in a laboratory soil bin. Design features of the chisel furrower showed that it has the characteristics of a narrow tillage tool and therefore it was subjected to three-dimensional analysis. The calculations of draught and soil coefficients were carried out at three model tool widths (0.026, 0.51 and 0.78m) and nine levels of tool rake angles (10, 20, 30, 40, 50, 60, 70, 80, 90°). Results showed that soil failure angles decreased with increases in rake angles. Soil failure angles increased with increases in tool widths. The soil mechanics equations over predicted thesoil resistance values slightly. The differences are however, not statistically significant. For minimum draught, the model tools could be operated at rakes angles ranging from 40° to 50° and tool width of 0.051 m. The results obtained showed that thesoil mechanics equations could be used to predict draught and soil coefficients on the model chisel furrower satisfactorily.