Transport mechanism of eroded sediment particles under freeze-thaw and runoff conditions  

作　　者：WANG Tian LI Peng HOU Jingming TONG Yu LI Jing WANG Feng LI Zhanbin 

机构地区：[1]State Key Laboratory of Eco-hydraulics in Northwest Arid Region,Xi'an University of Technology,Xi'an 710048,China [2]Key Laboratory of National Forestry Administration on Ecological Hydrology and Disaster Prevention in Arid Regions,Xi'an University of Technology,Xi'an 710048,China

出　　处：《Journal of Arid Land》2022年第5期490-501,共12页干旱区科学（英文版）

基　　金：funded by the National Natural Science Foundation of China(U2040208,52009104,52079106,42107087);the Shaanxi Province Innovation Talent Promotion Plan Project Technology Innovation Team(2020TD-023)。

摘　　要：Hydraulic erosion associated with seasonal freeze-thaw cycles is one of the most predominant factors,which drives soil stripping and transportation.In this study,indoor simulated meltwater erosion experiments were used to investigate the sorting characteristics and transport mechanism of sediment particles under different freeze-thaw conditions(unfrozen,shallow-thawed,and frozen slopes)and runoff rates(1,2,and 4 L/min).Results showed that the order of sediment particle contents was silt>sand>clay during erosion process on unfrozen,shallow-thawed,and frozen slopes.Compared with original soils,clay and silt were lost,and sand was deposited.On unfrozen and shallow-thawed slopes,the change of runoff rate had a significant impact on the enrichment of clay,silt,and sand particles.In this study,the sediment particles transported in the form of suspension/saltation were 83.58%–86.54%on unfrozen slopes,69.24%–84.89%on shallow-thawed slopes,and 83.75%–87.44%on frozen slopes.Moreover,sediment particles smaller than 0.027 mm were preferentially transported.On shallow-thawed slope,relative contribution percentage of suspension/saltation sediment particles gradually increased with the increase in runoff rate,and an opposite trend occurred on unfrozen and frozen slopes.At the same runoff rate,freeze-thaw process had a significant impact on the relative contribution percentage of sediment particle transport via suspension/saltation and rolling during erosion process.The research results provide an improved transport mechanism under freeze-thaw condition for steep loessal slopes.

关 键 词：FREEZE-THAW runoff conditions erosion process sediment particles transport mechanism 

分 类 号：P333[天文地球—水文科学]