Study on Dynamic Response of Blocking Structure and Debris Flow Impulsive Force considering Material Source Erosion

Abstract

The erosion of debris flows on the material source will affect the movement and impact of the debris flow. This paper adopted the coupled SPH-DEM-FEM to establish a complex dynamic model of the particle-fluid-erosion-structure of the debris flow and to assess the impact of erosion and sedimentation and analyse the dynamic response of the retaining structure of the debris flow. The strain-softening model was adopted to simulate the transformation of the debris flow body from the solid state to the transition state and finally into the liquid state. The coupled numerical analysis completely reproduces the debris flow erosion test, fitting the debris flow shape and thickness profile well. The impact process of the debris flow, the impact height behind the retaining dam, the deposition thickness, and the debris flow dynamic response significantly influence both with and without considering the effects of erosion. The results of this study are similar to existing literature and data, with the numerical analysis being consistent with the physical simulation tests in the existing literature, verifying the applicability of the SPH-DEM-FEM coupling analysis for assessing the debris flow impact retaining structures of erosion and sedimentation. The study also found that the dynamic response considering the debris flow impact and the retaining structures of erosion and sedimentation is more pronounced than when not considering erosion and sedimentation. Coupled numerical analysis can assess the potential effect of erosion and sedimentation, making a significant contribution to the assessment of the impact of debris flow and the design of retaining structures.

Dynamics of debris flow-induced impacting onto rigid barrier with material source erosion-entrainment process

“…The algorithm between debris flow particles and a rigid barrier is calculated by Eq. 6 (Li et al, 2022a):…”

“…The coupling algorithm between debris flow fluid, erodible material source body, and debris flow particles is calculated using Eq. 8 (Li et al, 2022a). The schematic diagram of SPH-DEM-FEM coupling numerical model is shown in Figure 2:…”

“…Fluidization occurs when the erodible material source is eroded, and entrainment occurs and forms part of the debris flow. At this point, the erodible material source changes from a transition state to a liquid state (Mangeney et al, 2007;Mangeney et al, 2010;Li et al, 2022a). To improve the reliability of the debris flow dynamic model, a complex constitutive model of the erodible material source should be considered (Lee and Jeong, 2018).…”

“…The research results helped to determine the impact force of debris flow. Li et al (Li B. et al, 2020;Li et al, 2022b) adopted the SPH-DEM-FEM method to study the interaction model of two-phase debris flow and the barrier. The research results were of great significance to the design of the barrier.…”

“…Coupled SPH-DEM-FEM technology can be well adapted to the simulation and calculation in the complex case of particle-fluidstructure. The coupled SPH-DEM-FEM method cannot only avoid the mesh distortion and analysis failure of two-phase debris flow but also accurately simulates the strain softening model of erodible material source and accurately calculate the barrier (Li et al, 2022b). This technique can be used to construct and calculate the complex coupled dynamic model of debris flow, erodible material source, and rigid barrier.…”