小开河灌区渠道的输水输沙特性①

依据小开河灌区运行10 a来的资料,总结灌区引水引沙条件和渠道断面特性,研究干渠不同渠段的引水分布特征和泥沙长距离输送、淤积特性。根据断面实测流量资料,给出输沙渠不同渠段的河宽、水深、流速、水力半径等水力参数与流量关系的水力几何形态指标,进而得出小开河灌区不同渠段的水流挟沙力与流量的关系。计算结果表明,设计流量下小开河灌区输沙渠沿程输沙能力变化不大,输沙渠中段由于渠道宽度较大,相同流量条件下的输沙能力较上、下段偏小约2 kg/m3。

Study on water and sediment transport characteristics in canals of Xiaokaihe irrigation district

Based on field data from Xiaokaihe irrigation district, the characteristics of water and sediment transport and the properties of canal sections are summarized.The diversion distribution characteristics of different segments of trunk canals and the properties of the long distance transport and deposition of sediment are studied.According to the sections' discharge data,some hydraulic geometry indexes are put forward,which illustrate the relationship between flow discharge and hydraulic parameters such as the canal width,depth, flow velocity and hydraulic radius.Consequently,the relationship between sediment carrying capacity and flow discharge of different segments is obtained.Results show that the capacity of flow and sediment transport changes little along the channel when discharge is the designed flow.With the same flow discharge,sediment carrying capacity in middle trunk canals is about 2 kg/m3 less than in the upper and lower canals in Xiaokaihe irrigation district.