Optimizing the Design of Soil-Mixing Blade Structure Parameters Based on the Discrete Element Method

A multi-parameter optimization-based design method for soil-mixing blades was proposed to address the issue of excessive straw residue in the seeding layer after maize straw incorporation. A discrete element model simulating the interaction between the soil-mixing blades, soil, and corn straw was established. The key structural parameters included the bending line angle ( α ), bending angle ( β ), side angle ( δ ), tangential edge height ( h ), and bending radius ( r ); the straw burial rate ( Y 1 ) and straw percentage in the seeding layer ( Y 2 ) were selected as evaluation indicators. Single-factor experiments determined the significance level ( p < 0.05) and the parameter range. A Box–Behnken response surface design, combined with analysis of variance (ANOVA), was employed to elucidate the influence patterns of the structural parameters and their interactions regarding straw burial performance. Multi-objective optimization yielded an optimal parameter combination: α = 55°, β = 100.01°, δ = 130°, h = 40.05 mm, and r = 28.67 mm. The simulation results demonstrated that this configuration achieved a Y 1 of 96.04% and reduced Y 2 to 35.25%. Field validation tests recorded Y 1 and Y 2 values of 96.54% and 34.13%, respectively. This study quantitatively elucidated the relationship between soil-mixing blade parameters and straw spatial distribution, providing a theoretical foundation for optimizing straw incorporation equipment.