OPTIMIZATION AND TESTING OF A SUBSOILING BLADE FOR RUPTURING COMPACTED SOIL LAYERS USING THE DISCRETE ELEMENT METHOD

To address severe soil compaction, high draft resistance, and low subsoiling efficiency in saline-alkali soils, a soil-breaking subsoiling shovel aimed at reducing draft and enhancing soil comminution was designed. A discrete element method (DEM) soil model with graded particle sizes was established using the Hertz–Mindlin contact model with JKR (Johnson–Kendall–Roberts) adhesion. Simulation analyses were combined with an orthogonal experimental design to optimize the shovel’s structural parameters and operating conditions. The optimal parameter combination—blade edge angle of 56.97°, blade inclination of 44.45°, and forward speed of 0.69 m·s⁻¹—resulted in a simulated draft of 2731.74 N and a maximum particle velocity of 2.75 m·s⁻¹. Field tests conducted at 0.69 m·s⁻¹ measured a draft of 2885.62 N, with a relative error of only 4.49% compared with the simulation, indicating high predictive reliability of the model. The mean soil comminution rate reached 57.79%, which is 64.5% higher than the conservation-tillage threshold (≥35%). These results demonstrate the usability and effectiveness of the proposed shovel. The optimized mechanical design reduces draft resistance while significantly improving soil fragmentation, and its overall operating performance meets the agronomic requirements for saline–alkali land improvement. Consequently, this design reduces energy consumption, enhances the soil environment for root growth, and exhibits strong agronomic applicability and environmental friendliness.