Link Between the Impact Mechanisms of Granular Flow-Dam Interaction and the Generated Seismic Signal: Insights From Laboratory Experiments

To manage debris flows, it is critical to both recognize potential impact mechanisms and evaluate, via physical models, associated impact forces. Seismic signals can be used to detect flows and infer flow properties, but inferring flow characteristics in channels with check dams and upslope deposits remains challenging. In this study, we conducted laboratory flume experiments to investigate the influence of varying flume inclination and pre-retained material (deposition upslope of the barrier) height on flow characteristics and impact mechanisms, and analyzed their correlation with seismic signals. The objective was to examine the impact of deposition upslope of the barrier on interactions between debris flows and check dams by combining seismic and dynamic parameters. We found that a frequency domain feature-based method can successfully filter out noisy signals. Results showed that it is possible to distinguish the impact mechanism of a granular flow in the presence of deposition upslope of the barrier from the seismic signals' attributes, that is, the peak signal amplitude envelope before granular flow overflow and its ratio to the peak amplitude of the control test without the barrier. Furthermore, the presence of check dams and upslope deposits in the debris flow channel significantly reduces the sensitivity of seismic signals to flow velocity. A key advantage of using the peak amplitude of the seismic signals generated by debris flows for identifying the impact mechanism is the potential for enhanced safety and cost-effectiveness compared with contact monitoring instruments such as force plates.