摘要
山区流域突发性暴雨洪水常携带大量泥沙及石块进入河道,使河流形态急剧改变,引发局部区域水沙灾害。结合野外调查与室内物理模型试验,探讨了不同来水来沙条件对宽窄相间和比降骤变河段河床形态的影响,研究了泥沙落淤发展趋势及河床演变特征。结果表明：上游有泥沙补给时,泥沙在宽窄相间河段落淤,呈现溯源淤积现象,流量越小,泥沙淤积向上游发展的速度越快,铺床作用明显,堆床作用较弱;随流量增大,淤积锋面向上游发展速度减小,铺床作用减弱,堆床作用增强。下游河段泥沙落淤使得原有的局部河床抬高,纵比降减小,落淤趋势进一步发展扩大,泥沙输移与河流形态之间形成一种互馈机制,相互影响制约。
Storms often cause serious rainfall runoff in mountain river areas,which results in slope scour and the failure of riverbed,causes large amounts of sediment to rivers,leading to a reconstruction of the riverbed and finally water and sediment disasters. Based on physical model experiment,this paper analyzed the development tendency of sediment deposition as well as features of fluvial processes under different discharges. Results show that sediment retrogressive deposition appeared in the wide-narrow region. The deposition speed changes with different flow discharge and sediment supply. Moreover,the processes of riverbed are more obvious than the elevation growth under small discharges. With further increasing of the flow rate,developing velocity of retrogressive deposition decreases. Downstream sediment deposition also changes the horizontal and vertical gradient of the original riverbed,which results in a reduction of longitudinal river slope,and further expands the trend of sediment deposition. Finally,sediment transport and riverbed processes are influenced each other.
作者
张晨玲
关见朝
方春明
王协康
ZHANG Chen-ling;GUAN Jian-chao;FANG Chun-ming;WANG Xie-kang(State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China;China Institute of Water Resources and Hydropower Research, Beijing 100048, China)
出处
《泥沙研究》
CSCD
北大核心
2018年第2期15-20,共6页
Journal of Sediment Research
基金
国家重点研发计划项目(2016YFC0402304)
国家自然科学基金项目(51639007)
国家国际科技合作专项(2015DFR70980)
关键词
山区河流
水沙变化
溯源淤积
河流形态
mountain river
water and sediment change
retrogressive deposition
fluvial morphology
