京杭运河底泥起动和冲刷率试验研究

Experimental Study on Sediment Start-up and Scour Rate of the Jing-hang Grand Canal

京杭运河是南水北调东线工程的重要输水通道,减少底泥冲刷引起的污染对保护其水质有重要的作用。利用文献中的底泥起动流速公式和冲刷率公式,推导出起动摩阻流速与湿密度公式、摩阻流速与冲刷率公式。以京杭运河底泥在水槽内进行不同湿密度的起动试验和不同水流条件下的冲刷率试验。试验结果用最小二乘法进行拟合,得到底泥起动时临界起动摩阻流速与湿密度的相关关系,冲刷时摩阻流速与冲刷率的相关关系。结果表明,有关试验数据的相关性较好,对实际工程应用有一定的指导意义。

The Jing-hang Grand Canal is an important water transport channel on the east route of the South-To-North Water Transfer Project. It plays an active role in the lessening of sediment scour to relieve water pollution and protect water quality. On the basis of the formula about scour of sediment and velocity stated in the literature, the relationships between frictional velocity and wet density, frictional velocity and scour rate are deduced. The start-up and scour rate of the Jing-hang Grand Canal sediment are experimented under different wet densities in the flume, and the measured data is fitted and simulated by least square method. The correlations between wet density and critical frictional velocity when start-up, and between frictional velocity and scour rate during scour are derived. The results of experiment and simulation show high correlations, thus the study can be used to guide relative engineering practice.