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两种工程堆积体边坡模拟径流侵蚀对比研究
引用本文:丁文斌,李叶鑫,史东梅,蒋光毅,汪三树,蒋 平.两种工程堆积体边坡模拟径流侵蚀对比研究[J].土壤学报,2017,54(3):558-569.
作者姓名:丁文斌  李叶鑫  史东梅  蒋光毅  汪三树  蒋 平
作者单位:1. 西南大学资源环境学院,西南大学水土保持生态环境研究所,重庆 400716;2. 重庆市水土保持生态环境监测总站,重庆,401147;3. 重庆市水利电力勘测设计研究院,重庆,400020
基金项目:重庆市水利局科技项目“生产建设项目弃土弃渣水土流失规律研究”,“重庆市生产建设项目水土流失危害研究”。
摘    要:基于对重庆市城镇建设中工程堆积体野外调查结果,选择广泛存在的紫色土和黄沙壤工程堆积体为研究对象,采用野外实地放水冲刷试验,对比分析了不同土石比及坡度的工程堆积体边坡径流侵蚀过程。结果表明:(1)工程堆积体土壤入渗率随冲刷过程呈先快速减小、后逐渐稳定的变化趋势,且波动幅度大小随冲刷流量的不同出现差异,下垫面稳定入渗率均在0.4~1.7 mm min~(-1)之间。(2)不同下垫面堆积体产流率随冲刷时间均呈先增加后稳定的谷峰交织变化趋势且随放水流量增大而显著增强;在相同放水流量时,黄沙壤堆积体平均产流率最大可为紫色土堆积体的1.89倍。(3)不同下垫面堆积体径流含沙量随冲刷时间呈先增加后稳定的波动趋势;径流含沙量在不同流量条件下介于0.21~1278.49 g L~(-1);冲刷过程中坡面面蚀向沟蚀的转化对径流含沙量有显著影响,最大可增加13.73倍;堆积体坡面侵蚀过程存在突变期、活跃期和稳定期3个阶段,细沟发生的偶然性和随机性对产沙量波动贡献率最大。(4)工程堆积体在不同放水流量条件下侵蚀泥沙颗粒粒径分布差异性明显,紫色土堆积体最大侵蚀泥沙颗粒均大于黄沙壤堆积体。研究结果可为重庆市城镇建设工程堆积体新增水土流失量预测和植被生态恢复提供重要科学依据。

关 键 词:产流产沙  入渗  工程堆积体  边坡  径流侵蚀  岩土侵蚀
收稿时间:2016/5/30 0:00:00
修稿时间:2017/2/20 0:00:00

Contrast Study on Simulated Runoff Erosion of Two Engineering Accumulation Slopes
DING Wenbin,LI Yexin,SHI Dongmei,JIANG Guangyi,WANG Sanshu and JIANG Ping.Contrast Study on Simulated Runoff Erosion of Two Engineering Accumulation Slopes[J].Acta Pedologica Sinica,2017,54(3):558-569.
Authors:DING Wenbin  LI Yexin  SHI Dongmei  JIANG Guangyi  WANG Sanshu and JIANG Ping
Affiliation:College of Resources and Environment,Southwest University,College of Resources and Environment,Southwest University
Abstract:Objective]Complex in composition,loose I structure and low in cohesion,engineering taluses are places where hazards,like soil erosion,mud-rock flow and landslip,are likely to occur under the action of rainfall runoff. Method] Based on field investigations of the engineering taluses formed during town construction processes in Chongqing,engineering taluses of purple soil and yellow sandy earth,commonly seen in the region,were selected as the objects of the study. On the taluses,field water scouring experiments were carried out to explore dynamic processes and mechanisms of water infiltrating, flow generating and sediment yielding on the underlying land surface under taluses different in rock content, relative to hydraulic condition,in an attempt to illustrate morphology and evolution process of the erosion and distribution characteristics of sediment particles in the erosion on the talus slopes. The field scouring experiments,designed to have three flow rates(i.e. 5,10,15 L min-1)and three slope gradients(i.e. 30°,35° and 40°),were conducted during the peiord from August to November,2012 at the Stationary Soil Erosion Experiment Site for Production and Construction Projects in the Southwest University,Chongqing.Result]Results show:(1)water infiltration rate in the soils of the taluses declined rapidly first and then gradually leveled off with scouring going on and magnitude of the fluctuation varied with scouring flow rate;water infiltration rate on the underlying surface varied in the range of 0.4~1.7 mm min-1,and the mean infiltration rate was in a power function relationship with the scouring flow rate,and so was the erosion modulus on the underlying surface of the taluses of different nature. It is,therefore,feasible to estimate erosion moduluses of taluses formed during the processes of various urban construction projects by scouring flow rate;(2)runoff yield rate on the talus slopes rose first and then fluctuated,exhibiting a wave-like curve with the scouring going on,which indicates that scouring flow rate is the major factor affecting runoff rate on the slope. With rising flow rate runoff rate increased significantly. When the scouring flow rates were the same,the mean runoff rate on talus slopes of yellow sandy earth was 1.89 times that on talus slopes of purple soil;(3)sediment concentration in runoff on talus slopes on different underlying surfaces rose first and then leveled off with the scouring going on and varied in the range of 0.21~1278 g L-1 relative to scouring flow rate;during the scouring process,soil erosion transformed from surface erosion to gully erosion, affecting significantly or multiplying sediment concentration in runoff by 13.73 times to the most extent;the erosion process on the talus slopes consisted of three stages,i.e. sudden changing stage,active stage and stabilization stage,corresponding to the three stages of erosion transformation from surface erosion to gully erosion,i.e. surface erosion,rill erosion and waning of rill erosion;contingency and randomness of the occurrence of rills were the two major contributors to the fluctuation of sediment yield;(4)particle size distribution of the erosion sediment from engineering talus slopes varied sharply with scouring flow rate and with composition of the talus slope;the particles of the erosion sediment from the talus of purple soil were larger in size than those from the talus of yellow sandy earth. The erosion sediment from the talus of purple soil varied in the range of 2~10 mm in particle size,and that from the talus of yellow sandy earth in the range of 0.1~0.5 mm;roughing of the talus slope as a result of erosion makes it harder to restore ecology of the waste dumping sites.Conclusion]All the findings of the study may serve as important scientific basis for prediction of soil and water loss and restoration of vegetation and ecology on engineering taluses in Chongqing.
Keywords:Runoff and sediment yield  Infiltration  Engineering talus  Slope  Runoff erosion  Rock and soil erosion
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