松花江干流造床水沙动力及河相关系的探究

Study on dominant flow-sediment conditions for bed reforming and hydraulic geometry in the main Songhua River

在分析松花江干流河道特性的基础上,基于实测资料,探究了造床水沙动力条件和河相关系。结果表明,枯水期和涨水期水流的造床作用不甚明显,主汛期水流是主要造床动力,退水期水流也具有一定造床作用;通过对比河道特征流量和计算得到的造床流量,说明常年洪水的造床作用依然十分有限,只有3~5年一遇的较大洪水才会形成较为明显的造床作用;河道河床呈现宽浅型,主槽相对窄小,洪漫滩地宽阔,中游段主槽河相关系系数√B/H在2~5之间,上游段和下游段大多超过5;基于河床最小活动性假设,得到河相关系与流量及含沙量之间的关系式,采用造床流量针对主槽进行检验,公式相符性较好。

Based on analysis of channel feature of the main Songhua River,dominant flow-sediment condition of bed forming and hydraulic geometries of the river has been studied.The results show that the main driving force for bed reformation is the main flood flow,the flow during recession period also play a certain role,the bed reforming effect of water flow during dry season and water rising period is not very obvious.Furthermore,by comparing the characteristic discharge with the calculated dominant discharge,it is explained that the bed-making effect of perennial flood flow is still limited,and only the larger flood flow with a return period of 3 to 5 years will form a more obvious effect.There is wide-shallow riverbed with relatively narrow main channel and the wide floodplain.The coefficient hydraulic geometry parameter of the main channel is between 2 and 5 in the middle reach and more than 5 in the upper and lower reach.Based on the hypothesis of minimum riverbed activity,the relationship between river hydraulic geometry coefficient and discharge and sediment concentration is obtained,which is better tested with the calculated dominant discharge in the main Songhua River.