Baffle system is a promising disaster mitigation measure, while the mechanism of debris-baffle interaction at grain scale has not been fully understood, and especially the effect of the unsteady nature of granular flow on debris-baffle interaction has not been detailly investigated. For this purpose, we conducted various small-scale model tests and used the three-dimensional discrete element method to assist the interpretation of the experimental results and extend research content. The granular arch that is formed between the baffle slit controls the debris-baffle interaction, which is completely different from the dead zone-dominant debris-barrier interaction mechanism represented by a rigid or flexible barrier. The particle size effect is controlled by the baffle jamming behavior. Larger particles facilitate the rapid formation of a stable force arch with larger energy-breaking efficiency. And flows with larger Froude number are not easy to form stable granular arches. Thus, the baffle array number, particle size, and construction site control the efficiency of baffle structure in deceleration of granular flows. Particularly, increasing the baffle array number restricts the recovery of flow mobility after the flow passes the baffle structure. In general, the construction of baffle at deposition area may not be an effective engineering options, because the impact force discrepancy on baffle array is larger by 28%, the generated energy dissipation is lower by 60.97%, the run-out distance by 10% and the spreading distance on the slope by approximately 40% for baffles in the deposition area compared with baffles constructed on slope.

挡板系统是一种很有前景的减灾措施，但在颗粒尺度上碎屑-挡板相互作用的机制尚未完全了解，尤其是颗粒流的非定常性质对碎屑-挡板相互作用的影响尚未得到详细研究。为此，我们进行了各种小规模模型试验，并采用三维离散元法来辅助解释实验结果，扩展研究内容。挡板狭缝之间形成的颗粒拱形控制碎片-挡板相互作用，这与以刚性或柔性屏障为代表的死区-主导碎片-屏障相互作用机制完全不同。粒度效应由挡板干扰行为控制。较大的颗粒有助于快速形成稳定的力拱，并具有更高的能量破坏效率。且弗劳德数较大的流动不易形成稳定的粒状拱。因此，挡板阵列数量、粒度和施工现场控制挡板结构在颗粒流减速中的效率。特别是，增加挡板阵列数限制了流动通过挡板结构后流动性的恢复。一般来说，在沉积区建造挡板可能不是一个有效的工程选择，因为挡板阵列上的冲击力差异大了 28%，产生的能量耗散低了 60.97%，