Macro‐ and Microscopic Insight Into the Impact of Initial Anisotropy on the Evolution of Soil Arching

ABSTRACT Further investigation into the evolution of soil arching influenced by initial anisotropy remains essential. In this study, the discrete element method is employed to analyze trapdoor models with varying degrees of initial anisotropy, which are calibrated using data from previous experimental studies. The results indicated that the overall trend of the ground reaction curves remains consistent across samples with varying initial bedding angles, with three distinct stages. The variation in the ultimate soil arching ratio closely parallels that of the minimum ratio, also exhibiting an approximately symmetric “M”‐shaped pattern, with the minimum value occurring at θ = 45°. Compared with isotropic spherical materials, anisotropic materials show a weaker soil arching effect. The evolutionary pathways of soil arching can be categorized into two distinct patterns: the quasi‐symmetrical arch and the deflection arch. The dominant direction of force chains progressively aligns with the imposed bedding angle. Increasing the initial bedding angle leads to progressively more concentrated contact force distributions and increasingly robust force chain structures. The distribution of normal forces, tangential forces, and contact number is strongly influenced by the initial bedding angle.