Effects of river flow velocity on the formation of landslide dams

作     者：CHEN Kun-Ting CHEN Xiao-Qing HU Gui-Sheng KUO Yu-Shu CHEN Hua-Yong 

作者机构：Key Laboratory of Mountain Hazards and Earth Surface ProcessesInstitute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China Department of Hydraulic and Ocean EngineeringNational Cheng Kung UniversityTainan 70101Chinese Taipei CAS Center for Excellence in Tibetan Plateau Earth SciencesBeijing 100101China University of Chinese Academy SciencesBeijing 100049China 

出 版 物：《Journal of Mountain Science》 (山地科学学报（英文）)

年 卷 期：2019年第16卷第11期

页      面：2502-2518页

核心收录：

学科分类：0709[理学-地质学] 0819[工学-矿业工程] 081803[工学-地质工程] 08[工学] 0303[法学-社会学] 0708[理学-地球物理学] 0818[工学-地质资源与地质工程] 0705[理学-地理学] 0815[工学-水利工程] 0706[理学-大气科学] 0816[工学-测绘科学与技术] 0813[工学-建筑学] 0704[理学-天文学] 0833[工学-城乡规划学] 0713[理学-生态学] 0834[工学-风景园林学（可授工学、农学学位）] 

基　　金：supported by the National Natural Science Foundation of China(Grants No.41661144028,41771045 and 41501012) the CAS "Light of West China" Program the Foundation for Young Scientist of Institute of Mountain Hazards and Environment,CAS(Grant No.SDS-QN-1912) the Foundation of Youth Innovation Promotion Association,CAS(Grant No.2017425) 

主　　题：Natural dam Landslide Depositional capacity of landslide debris Erosive capacity of water flows 

摘      要：Natural dams are formed when landslides are triggered by heavy rainfall during extreme weather events in the mountainous areas of *** landslide debris movement,two processes occur simultaneously:the movement of landslide debris from a slope onto the riverbed and the erosion of the debris under the action of high-velocity river *** the rate of landslide deposition in a river channel is higher than the rate of landslide debris erosion by the river flow,the landslide forms a natural dam by blocking the river *** this study,the effects of the rates of river flow erosion and landslide deposition(termed the erosive capacity and depositional capacity,respectively)on the formation of natural dams are quantified using a physics-based approach and are tested using a scaled physical *** define a dimensionless velocity index vde as the ratio between the depositional capacity of landslide debris(vd)and the erosive capacity of water flow(ve).The experimental test results show that a landslide dam forms when landslide debris moves at high velocity into a river channel where the river-flow velocity is low,that is,the dimensionless velocity index vde*** debris will not have sufficient depositional capacity to block stream flow when the dimensionless velocity index vde*** depositional capacity of a landslide can be determined from the slope angle and the friction of the sliding surface,while the erosive capacity of a dam can be determined using river flow velocity and rainfall *** methodology described in this paper was applied to seven landslide dams that formed in Taiwan on 8 August 2009 during Typhoon Morakot,the Tangjiashan landslide dam case,and the Yingxiu-Wolong highway K24 landslide *** dimensionless velocity index presented in this paper can be used before a rainstorm event occurs to determine if the formation of a landslide dam is possible.