Dynamic Response Study of Impulsive Force of Debris Flow Evaluation and Flexible Retaining Structure Based on SPH‐DEM‐FEM Coupling

Abstract

Flexible retaining structure is demonstrated to be an effective measure for debris flow prevention in mountainous areas, which can effectively separate water and stone, reduce particle mass, and dissipate kinetic energy. In order to explore the impulsive force and dynamic response of flexible retaining structure impacted by solid-liquid two-phase debris flow, a complex dynamic interaction model of particle-fluid-structure has been established by employing the SPH-DEM-FEM coupling numerical analysis method. In the present study, the process, impulse force, and dynamic response of a flexible retaining structure subjected to debris flow under different slopes were investigated, respectively. The numerical results are compared with those of the calculation formula of the peak impulsive force of the semiempirical debris flow. Meanwhile, the effectiveness of the coupling numerical simulation is verified. The simulation results show that the coupled SPH-DEM-FEM numerical analysis method can visualise the impact of the solid-liquid two-phase debris flow on the flexible retaining structure, reproducing the impact, retaining, water-stone separation, climbing, silting, and deposition process of debris flow. The dynamic time-history curve of the coupling numerical analysis method for the flexible retaining structure is consistent with the results of the existing literature. The debris flow evaluation results of flexible retaining structure impacted by solid-liquid two-phase debris flow are in an order of magnitude with the empirical formula results. Moreover, the results are reliable. The obtained results have a certain reference value for the study on the impulsive force and dynamic response of the flexible retaining structure impacted by solid-liquid two-phase debris flow and the engineering design of the flexible retaining structure.

Two‐particle debris flow simulation based on SPH

“…CFD-DEM 32,33 supports various fluid-solid interaction models and is suitable for large-scale simulations, but demands high computational resources and has complex coupling, with stability and accuracy challenges. SPH-DEM-FEM 34,35 is suitable for multiphysics coupling, offering high-fidelity simulations and flexible coupling, but with high computational complexity, parameter tuning difficulties, and potential stability issues. Overall, research into the bidirectional interaction in solid-liquid coupling has addressed the limitations of unidirectional interaction, but challenges like flow rate and timestep constraints remain.…”

Bi‐Linear Laws Govern the Impacts of Debris Flows, Debris Avalanches, and Rock Avalanches on Flexible Barrier

“…Besides physical experiments and theoretical analysis, many numerical methods have been applied to investigate the impacts of geophysical flows on flexible barriers, such as mesh‐free methods (smoothed particle hydrodynamics [SPH], Fávero Neto et al., 2020; Material Point Method, Vicari et al., 2022; discrete element method [DEM], Albaba et al., 2017), grid‐dependent methods (finite element method [FEM], Brighenti et al., 2013), and coupled frameworks (SPH‐DEM‐FEM, B. Li, Wang, et al., 2021; DEM‐FEM, Liu et al., 2020; computational fluid dynamics [CFD] coupled with DEM, Kong, Li, et al., 2021; Lattice Boltzmann Method coupled with DEM and FEM, Leonardi et al., 2016; CFD‐FEM, Von Boetticher et al., 2011). Nonetheless, simplifications of flow dynamics and flexible barriers have prevented a deeper understanding of the underlying relations and mechanisms of the flow‐barrier interactions.…”

“…On the one hand, the solid‐fluid nature of a geophysical flow plays a crucial role in predicting its propagation and impact (De Haas et al., 2021; Iverson, 1997; Pudasaini & Mergili, 2019) but has commonly been modeled as pure continuum or granular flows (Albaba et al., 2017; Liu et al., 2020; Von Boetticher et al., 2011). On the other hand, permeable flexible barrier systems (Figure 1a) are simulated as membranes (Leonardi et al., 2016; Vicari et al., 2022), and net units are generated in a 2D plane (Brighenti et al., 2013; Kong, Li, et al., 2021; B. Li, Wang, et al., 2021) by ignoring the cable‐ring‐ring slidings in a 3D space. However, these omitted in‐flow multiphase and in‐barrier multiway interactions are essential for accurately predicting systematic structure deformations, evolving load sharings and distributions, and thus peak barrier load.…”