Experimental study of debris-flow entrainment over stepped-gradient beds incorporating bed sediment porosity

doi:10.1016/j.enggeo.2020.105708

CORC > 成都山地灾害与环境研究所 > 中国科学院水利部成都山地灾害与环境研究所 > 山地灾害与地表过程重点实验室

	Experimental study of debris-flow entrainment over stepped-gradient beds incorporating bed sediment porosity
	Li, Pu 3; Wang, Jiading 3; Hu, Kaiheng 1,2; Wang, Fei 3
刊名	ENGINEERING GEOLOGY
	2020-09-05
卷号	274 页码:105708
关键词	Debris flow Entrainment behaviour Bed porosity Pore pressure variation Stepped-gradient
ISSN号	0013-7952
DOI	10.1016/j.enggeo.2020.105708
通讯作者	Wang, Jiading(wangjd@nwu.edu.cn)
产权排序	2
文献子类	Article
英文摘要	The incorporation of bed sediment by a natural debris flow can cause significant growth in its size and destructive potential. In this study, the erosion features of debris flows in channels with stepped-gradient beds were determined based on field observations and flume experiments. Field investigations revealed that channel sections with abrupt bed slope variations were eroded more intensely than others. A series of small-scale flume tests were conducted to study the pore pressure variations in erodible bed sediment and the basal entrainment behaviour of debris flows in channels with stepped-gradients. Reference tests on a uniform bed slope demonstrate that inflection points in the bed longitudinal profile greatly alter the debris mixture flow pattern and accelerate entrainment. Pore pressure generation in the bed sediment supports debris flow entrainment by reducing basal friction. Peak pore pressures at concave sites were approximately two times higher than those observed at convex sites, likely due to large changes in debris flow dynamics and intense interactions between the flow mixture and bed sediment. Low bed sediment porosities will increase the interlocking of grain particles, promote the formation of clusters and enhance the strength of the grain skeleton, suppressing basal entrainment. In the flume tests, lower peak pore pressures were observed as bed porosity decreased, possibly due to fewer connecting channels for pore fluid pressure to transmit in the compacted bed sediment. Dimensionless analysis indicates that pore pressure fluctuations in the bed sediment were mainly generated by the overriding debris flow. A new entrainment formula of debris flow over stepped-gradient beds is proposed based on flume tests and theoretical analyses, which may aid future debris flow modelling and hazard assessments.
电子版国际标准刊号	1872-6917
资助项目	National Natural Science Foundation of China[41371039] ; National Key Research and Development Plan[2018YFC1504703]
WOS关键词	NUMERICAL-SIMULATION ; MODEL ; EROSION ; MECHANISMS ; DEPOSITION ; BEHAVIOR ; RUNOUT ; LOESS
WOS研究方向	Engineering ; Geology
语种	英语
出版者	ELSEVIER
WOS记录号	WOS:000558028500014
资助机构	National Natural Science Foundation of China ; National Key Research and Development Plan
内容类型	期刊论文
源URL	[http://ir.imde.ac.cn/handle/131551/35444]
专题	成都山地灾害与环境研究所_山地灾害与地表过程重点实验室
通讯作者	Wang, Jiading
作者单位	1.Institute of Mountain Hazards and Environment, Chinese Academy of Sciences & Ministry of Water Conservancy, Chengdu, Sichuan 610041, China 2.Key Laboratory of Mountain Hazards and Earth Surface Processes, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China; 3.State Key Laboratory of Continental Dynamics/Department of Geology, Northwest University, Xi'an, Shaanxi 710069, China;
推荐引用方式 GB/T 7714	Li, Pu,Wang, Jiading,Hu, Kaiheng,et al. Experimental study of debris-flow entrainment over stepped-gradient beds incorporating bed sediment porosity[J]. ENGINEERING GEOLOGY,2020,274:105708.
APA	Li, Pu,Wang, Jiading,Hu, Kaiheng,&Wang, Fei.(2020).Experimental study of debris-flow entrainment over stepped-gradient beds incorporating bed sediment porosity.ENGINEERING GEOLOGY,274,105708.
MLA	Li, Pu,et al."Experimental study of debris-flow entrainment over stepped-gradient beds incorporating bed sediment porosity".ENGINEERING GEOLOGY 274(2020):105708.