Experimental and three-dimensional numerical investigations of the impact of dry granular flow on a barrier

Author(s):  
R Law ◽  
G Zhou ◽  
C Ng ◽  
W Tang
2019 ◽  
Vol 07 (05) ◽  
pp. 1-15
Author(s):  
Chun Liu ◽  
Zhixiang Yu ◽  
Junfei Huang

Landslides ◽  
2020 ◽  
Author(s):  
Sixia Gong ◽  
Tao Zhao ◽  
Jidong Zhao ◽  
Feng Dai ◽  
Gordon G. D. Zhou

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.


2018 ◽  
Vol 51 (7) ◽  
pp. 2191-2205 ◽  
Author(s):  
Yuan-Jun Jiang ◽  
Zheng-Zheng Wang ◽  
Yue Song ◽  
Si-You Xiao

2020 ◽  
Vol 57 (2) ◽  
pp. 236-245 ◽  
Author(s):  
Clarence Edward Choi ◽  
Charles Wang Wai Ng ◽  
Haiming Liu ◽  
Yu Wang

Some types of barriers are designed with a clearance between the bottom of the barrier and the channel bed. This feature allows small discharges to pass, thereby reducing the maintenance required over the service life of the barrier. Aside from the practical function of a clearance, it influences the impact force, jump height, and discharge. In this paper, a series of physical experiments was conducted using a 6 m long flume to model the interaction between dry granular flow and rigid barrier with a basal clearance. The ratio between the clearance and particle diameter Hc/D was varied from 0 to 10. The channel inclination was varied from 15° to 35° to achieve different Froude numbers before impact. A new impact model for predicting impact force exerted on the barrier with a basal clearance is presented and evaluated. Results reveal that Hc ≥ 3D is capable of reducing the impact force and overflow. Findings from this study highlight the importance of considering the effects of basal clearance on the design of multiple-barrier systems.


2018 ◽  
Vol 340 ◽  
pp. 39-51 ◽  
Author(s):  
Yuan-Jun Jiang ◽  
Xiao-Yi Fan ◽  
Tian-Hua Li ◽  
Si-You Xiao

Landslides ◽  
2020 ◽  
Vol 17 (6) ◽  
pp. 1465-1483 ◽  
Author(s):  
Xiao Siyou ◽  
Su Lijun ◽  
Jiang Yuanjun ◽  
Qu Xin ◽  
Xu Min ◽  
...  

Author(s):  
C.W.W. Ng ◽  
Haiming Liu ◽  
Clarence E. Choi ◽  
Aastha Bhatta ◽  
Min Zheng

A basal clearance is usually designed beneath barriers to enable sufficient discharge to minimise the maintenance work over service life. Current design guidelines for multiple barriers usually neglect the influence of basal clearance, resulting in either an over-conservative or a non-conservative design impact force acting on the subsequent barriers. In this study, physical model tests were carried out to investigate the effects of basal clearance height (Hc) beneath first barrier on the interaction between dry granular flow and dual rigid barriers. A new approach based on the hydrodynamic equation is proposed to estimate the impact force on the second barrier exerted by the basal discharge from the first barrier. This basal discharge can attenuate the impact force exerted on the second barrier by dissipating the kinetic energy of landing flow and apportioning the load contributions from discharge and overflow. For the first barrier with a barrier height HB1 that was twice of the flow depth h0, the impact force on the second barrier was governed by overflow when Hc/h0 ≤ 0.6 and was dominated by basal discharge when Hc/h0 ≥ 0.8. These two criteria provide a basis for optimising the impact forces for multiple-barrier systems with basal clearances.


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