Dynamic and Seismic Characteristics of Granular Flows under Different Flow Regimes: Insights from Laboratory Flume Experiments

Granular flows, such as landslides and rock avalanches, are a prevalent geological hazard in mountainous regions, necessitating accurate dynamic modeling for disaster prevention. We investigate the influence of particle composition and flow regimes on granular flow dynamics and seismic response through a series of flume experiments. By varying particle size distributions and flume inclinations, we analyzed kinematic properties, seismic signals, and the interplay between flow regimes and seismic characteristics. The results demonstrate that particle composition significantly impacts flow mobility, with an optimal proportion of large particles maximizing flow mobility. Seismic signals, including peak amplitude and power spectral density, showed a strong coupling with collisional stresses and exhibited a biphasic positive correlation with flow dynamics. We employ a unified framework based on the dimensionless amplitude parameter and the Savage number to interpret seismic responses across flow regimes. We found that frictional flows generate seismic signals through bulk impacts, while collisional flows do so via inter-particle collisions. Our study advances the understanding of granular flow dynamics and their seismic signatures, highlighting the importance of refined models to disentangle the mechanisms of frictional and collisional interactions. These findings enhance our understanding of seismic-based debris flow monitoring and hazard assessment, highlighting the need for refined models to better interpret granular flow behaviors in natural environments.