Abstract: The problem of soil cutting widely exists in engineering fields such as tunnelling, port and waterway dredging, geological drilling, and civil construction. Accurately characterizing the three-dimensional soil failure surface in front of the cutting tool during the soil cutting process is of great significance for analyzing soil disturbance states, evaluating tool cutting performance, and understanding soil-tool interaction mechanisms. A nonlinear elastoplastic damage-based constitutive model is employed to describe the deformation and failure process of soil. Based on the characteristics of damage energy dissipation per unit area of the soil medium, a new numerical method is proposed to directly characterize the three-dimensional soil failure surface. Numerical simulations of flat-tool cutting processes under various operating conditions verify the effectiveness and robustness of the proposed characterization method. The influence of cutting angle and depth on the width, rupture distance, soil disturbance area, and shear failure angle of the three-dimensional soil failure surface is discussed in combination with theoretical calculations. Furthermore, the shape of the three-dimensional soil failure surface for complex-shaped tools obtained through this numerical method is consistent with experimental results, further validating the applicability of the proposed method for complex tool scenarios.

Key words: soil cutting, damage energy dissipation, failure profile, complex tool, numerical simulation