采砂活动影响下的河道水面比降变化

Water surface slope variation under sand extraction activity in the Ganjiang River

受河道无序采砂的影响,局部河段水流流态变得复杂,从而影响船舶通航条件。根据实测河道地形资料及水文资料,分析了赣江下游樟树至外洲河道采砂后局部河床最大比降的历年变化,并运用一维水流数学模型计算了历年不同流量的河道水面线变化,分析了水面线局部最大比降与河床比降的关系。结果表明,受河道采砂影响,局部水面比降明显增加;局部水面最大比降与河床比降密切相关;随着流量的增加,水面最大比降减小,水面比降受河床的影响程度减弱。

Due to the unordered sand extraction, the local flow pattern becomes more complex and the navigation conditions are effected. According to the measured river terrain data and hydrological data, the annual variations of maximum riverbed slope have been analyzed for the river reach betw een Zhangshu to Waizhou in the downstream of Ganjiang River after sand extraction. The river w ater surface variation is calculated using the one-dimensional mathematical flow model under differentflow discharge conditions, and the relationship betw een the local maximum w ater surface slope and riverbed slope is analyzed. The results show thatlocal water surface slope increases significantly and local maximum water surface slope is closely related to riverbed slope due to the effects of sand extraction, and the maximum water surface slope decreases and the effects of riverbed on w ater surface slope weaken with the increasing of river flow discharge.