Case History of the Disastrous Debris Flows of Tianmo Watershed in Bomi County, Tibet, China: Some Mitigation Suggestions

作     者：GE Yong-gang CUI Peng SU Feng-huan ZHANG Jian-qiang CHEN Xing-zhang 

作者机构：Key Laboratory of Mountain Hazards and Earth Surface Processes / Institute of Mountain Hazards and Environment Chinese Academy of Sciences School of Environment and Resources Southwest University of Sciences and Technology 

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

年 卷 期：2014年第11卷第5期

页      面：1253-1265页

核心收录：

学科分类：08[工学] 081501[工学-水文学及水资源] 0837[工学-安全科学与工程] 0815[工学-水利工程] 

基　　金：supported by the Key Program of National Natural Science Found of China(Grant No.41030742) the Grand Program of National Natural Science Found of China(Grant No.41190084) 

主　　题：Debris Flow Characteristics Hazard Chain Formation Condition Tianmo Watershed 

摘      要：Debris flows and landslides, extensively developing and frequently occurring along Parlung Zangbo, seriously damage the Highway from Sichuan to Tiebt(G318) at Bomi County. The disastrous debris flows of the Tianmo Watershed on Sept. 4, 2007, July 25, 2010 and Sept. 4, 2010, blocked Parlung Zangbo River and produced dammed lakes, whose outburst flow made 50 m high terrace collapse at the opposite bank due to intense scouring on the foot of the terrace. As a result, the traffic was interrupted for 16 days in 2010 because that 900 m highway base was destructed and 430 m ruined. These debris flows were initiated by the glacial melting which was induced by continuous higher temperature and the following intensive rainfall, and expanded by moraines along channels and then blocked Parlung Zangbo. At the outlet of watershed,the density, velocity and peak discharge of debris flow was 2.06 t/m3, 12.7 m/s and 3334 m3/s, respectively. When the discharge at the outlet and the deposition volume into river exceeds 2125 m3/s and 126×103 m3, respectively, debris flow will completely blocked Parlung Zangbo. Moreover,if the shear stress of river flow on the foot of terrace and the inclination angel of terrace overruns 0. 377 N/m2 and 26°, respectively, the unconsolidated terrace will be eroded by outburst flow and collapse. It was strongly recommended for mitigation that identify and evade disastrous debris flows, reduce the junction angel of channels between river and watershed, build protecting wall for highway base and keep appropriate distance between highway and the edge of unconsolidated terrace.