Discrete element analysis of dry granular flow impact on slit dams

Sixia Gong,Gordon G D Zhou,Jidong Zhao,Tao Zhao,Feng Dai

doi:10.1007/s10346-020-01531-2

Abstract

Slit dam is an open-check barrier structure widely used in mountainous regions to resist the destructive impacts of granular flows. To examine the dynamics of granular flow impact on slit dams, a numerical study by discrete element method (DEM) is presented in this article. The study considers dry granular materials flowing down a flume channel and interacts with slit dams installed at the lower section of the flume. The particle shape is explicitly considered by particle clumps of various aspect ratios. The slit dams are modeled as rigid and smooth rectangular prisms uniformly spaced at in the flume. Four key stages of granular flow impact on the slit dams have been identified, namely, the frontal impact, run up, pile up, and static deposition stages. In the impact process, the kinetic energy of the granular flow is dissipated primarily by interparticle friction and damping. The trapping efficiency of the slit dams decreases exponentially with the relative post spacing, while it increases with the particle clump aspect ratio. The numerical results can provide new insights into the optimization of relative post spacing for slit dam design.

Highlights

As one of the common geological hazards, granular flow can significantly threaten human lives, structures and infrastructures, and lifeline facilities worldwide due to its fast-moving velocity, long runout distance, and high impact force (Chen et al 2015; Hürlimann et al 2006; Iverson 1997)
The impacts of dry granular flows on slit dams of various post spacings have been analyzed via numerical flume tests using the open-source discrete element method (DEM) code ESyS-Particle
The obtained numerical results reveal the dynamics of debris-dam interactions, with the potential applications to a rigid slit dam design

Summary

Introduction

As one of the common geological hazards, granular flow can significantly threaten human lives, structures and infrastructures, and lifeline facilities worldwide due to its fast-moving velocity, long runout distance, and high impact force (Chen et al 2015; Hürlimann et al 2006; Iverson 1997). A slit dam usually consists of an array of densely spaced concrete columns These columns may serve as effective measures to dissipate the impact energy of granular flow and collectively help to retain a certain portion of coarse solids (Cui et al 2018). It can control the peak granular discharge by allowing a relatively small portion of debris materials to pass through the slits. This approach may significantly reduce the destructive power of granular flow and the possibility of dam failure (Goodwin and Choi 2020). They further concluded that the complete blockage would occur for a slit dam with b/dmax being smaller than 1.5

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