Computational assessment of baffle performance against rapid granular flows
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Yu Huang I Bei Zhang I Chongqiang Zhu
Computational assessment of baffle performance against rapid granular flows
Abstract Rapid granular flows are one of the most catastrophic geo-disasters frequently encountered in mountainous areas. The baffle structure has been demonstrated to be an effective measure for decreasing the destructivity of such geo-disasters. In this paper, a flow–baffle interaction model based on the 3D discrete element method is adopted to assess the baffle performance, hoping to facilitate the optimal design of baffles. A multiple-indicator-based framework, which covers three aspects and six metrics, is proposed and used to thoroughly and quantitatively assess the energy dissipation capacity, deposition regulation function, and failure potential of the baffle structure considering the particle size and baffle shape effect. Results indicate that the particle size significantly affects the baffle performance, and several linear relationships are proposed to account for the effect of the particle size, which may serve to improve engineering structural design. The square baffle performs better than the triangular baffle even though they have identical transverse blockage. Investigation of the patterns of the force chain distribution in granular flows confirms that the flow–baffle interaction is controlled by the evolution of force chains. The particle size and baffle shape effect can be explained by the difference in stability of arches that form during flow–baffle interaction. In addition, the quantification of energy loss due to inelastic contact between particles and baffles reveals that enhanced particle–particle interaction is the dominant energy dissipation mechanism, accounting for more than 80–90% of the total energy loss. Keywords Baffle performance . Flow-structure interaction . Particle size effect . Baffle shape effect . Discrete element method Introduction In mountainous areas, geo-granular materials surge downslope under the effect of gravity, resulting in geo-disasters such as debris flows and rock avalanches (Hungr et al. 2014), which are among the most catastrophic geo-events. Such disasters have resulted in economic losses and casualties (Dowling and Santi 2014) because they can occur without warning, usually move at extremely high velocity (> 5 m/s), and have a long run-out distance. There have been well-known recent events, such as the 2015 Shenzhen landslide, which killed 77 people (Zhan et al. 2018), and the 2014 Oso landslide, the economic loss of which exceeded US$ 120 million (Wartman et al. 2016). As a result, scientific and engineering communities have increasingly addressed disaster prevention design. Two types of prevention measure have commonly been implemented, namely active measures (e.g., check dams and baffle systems) and passive measures (e.g., hazard mapping) (Vagnon 2020). It is sometimes inescapable that critical buildings and infrastructure are located within a hazardous zone because of the limitations of land use, and there is thus an urgent need to establish
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