节点文献
Debris flow impact on flexible barrier: effects of debrisbarrier stiffness and flow aspect ratio
【摘要】 Conventionally, flexible barriers are rated based on their ability to resist a free-falling boulder with a particular input energy. However, there is still no well-accepted approach for evaluating performance of flexible barrier under debris flow impact. In this study, a large-nonlinear finite-element model was used to back-analyze centrifuge tests to discern the effects of impact material type, barrier stiffness, and flow aspect ratio(flow height to flow length) on the reaction force between the impacting medium and flexible barrier. Results show that, in contrast to flexible barriers for resisting rockfall, the normal impact force induced by the highly frictional and viscous debris is insensitive to barrier stiffness. This is because the elongated distributions of kinetic energy are mainly dissipated by the internal and boundary shearing, and only a small portion is forwarded to the barrier. Furthermore, a new stiffness number is proposed to characterize the equivalent stiffness between a debris flow or a boulder, and a flexible barrier. Under the circumstance of an extremely elongated debris flow event, i.e., low aspect ratio, the load on a barrier is dominated by the static component and thus not sensitive to the barrier stiffness.
【Abstract】 Conventionally, flexible barriers are rated based on their ability to resist a free-falling boulder with a particular input energy. However, there is still no well-accepted approach for evaluating performance of flexible barrier under debris flow impact. In this study, a large-nonlinear finite-element model was used to back-analyze centrifuge tests to discern the effects of impact material type, barrier stiffness, and flow aspect ratio(flow height to flow length) on the reaction force between the impacting medium and flexible barrier. Results show that, in contrast to flexible barriers for resisting rockfall, the normal impact force induced by the highly frictional and viscous debris is insensitive to barrier stiffness. This is because the elongated distributions of kinetic energy are mainly dissipated by the internal and boundary shearing, and only a small portion is forwarded to the barrier. Furthermore, a new stiffness number is proposed to characterize the equivalent stiffness between a debris flow or a boulder, and a flexible barrier. Under the circumstance of an extremely elongated debris flow event, i.e., low aspect ratio, the load on a barrier is dominated by the static component and thus not sensitive to the barrier stiffness.
【Key words】 Debris flow; Flexible barrier; Impact; Stiffness; Flow aspect ratio;
- 【文献出处】 Journal of Mountain Science ,Journal of Mountain Science 山地科学学报(英文版) , 编辑部邮箱 ,2019年07期
- 【分类号】P642.23
- 【被引频次】1
- 【下载频次】13