ABSTRACT Soil inrush is a typical silo‐type geohazard. To investigate particle behavior during this process, DEM‐CFD numerical simulation was conducted to comprehensively analyze the evolution of velocity fields, stress fields, force chains, and coordination numbers. The results indicate that the arching force chains near the inrush point continuously break and re‐form at higher locations as the inrush progresses. The interior of the arch, characterized by rapid particle transport, a sharp stress decrease, and a low coordination number, indicates that the soil mass is highly loosened and experiences continuous particle loss. This loosened instability zone progressively develops upward. Once the instability zone reaches the ground surface, it rapidly expands across the surface, causing surrounding particles to converge toward the center. Based on the evolution of microscopic contact behavior and macroscopic flow characteristics, this study reveals the dynamic transition mechanism of the soil mass. Specifically, five zones with distinct particle‐behavior characteristics are identified during the early stage of soil inrush, and a sixth zone subsequently emerges near the ground surface as surface collapse develops. Finally, a soil state model based on the ellipsoid of motion was established and used to delineate the influence range of a documented inrush accident. This study systematically investigates particle behavior during soil inrush and provides guidance for inrush prevention and mitigation in concealed engineering projects.
Meng et al. (Fri,) studied this question.