Gravity-driven geophysical flows, such as landslides and avalanches, pose significant hazards due to their instability and destructive potential. A mechanistic understanding of the obstacle-granular interaction processes and their coupled effects on deposition dynamics is crucial for designing engineered barriers. This study investigates the postimpact evolution of downslope granular flow and its subsequent deposition dynamics on horizontal base within a two-dimensional channel configuration. Through laboratory experiments and particle image velocimetry measurements, we identify a “third jump” phenomenon arising from late-stage lateral particle convergence. Furthermore, we demonstrate the complete elimination of the granular vacuum zone behind the obstacle, a phenomenon driven by subcritical basal flow and the low hysteresis of glass beads, which allows particles to “creep” into the void. Our results reveal a fundamental decoupling between localized obstacle-induced disturbances and global deposition dynamics, which remain primarily governed by the initial mass. We provide robust scaling laws for deposit height, run-out distance, and spreading velocity, advancing the predictive framework for geophysical hazard assessment beyond existing unobstructed flow models.

Close

PrevNext

View figure in article

• Geophysical fluid dynamics
• Granular avalanches
• Granular flows