河道型水库库区淤积形态数值模拟研究

The study on sedimentation form in the reservoir area of Altash Reservoir

阿尔塔什水库是新疆叶尔羌河流域重点规划的河道型水库,具有防洪、灌溉、发电等综合功能,但库沙比86.06,小于标准制定100年,泥沙淤积情况较为严重。为研究其泥沙淤积特性,通过MIKE 21软件建立二维输沙模型,对阿尔塔什水库坝后区域水位、横纵剖面淤积形态变化、水库淤积量及库容变化进行研究。结果表明:河流横纵断面的水位变化情况与运行工况设定要求基本吻合。纵剖面淤积形态变化显示河床泥沙淤积情况并不严重,坝后河床最终淤积高程尚未达到排沙洞的底板高程;坝址处出现冲刷漏斗,断面淤积后的河底高程与深泓线上的淤积高程基本相同;随运行年份的增加泥沙淤积量越来越大,但最终泥沙淤积高度并未达到死水位1770m,兴利库容并未减少。

The Altash Reservoir which has the comprehensive functions of flood control,irrigation and power generation is a key river type reservoir in the Yerqiang River basin of Xinjiang province.But the ratio of Altash Reservoir to sand is 86.06 which is less than 100 years formulated by the standard,and the ratio caused a serious sedimentation in the reservoir.In order to study the reservoir sediment characteristics,our study established a two-dimensional sediment transport model by MIKE 21 software to simulate the distribution of water level in the area behind the dam of Altash Reservoir,the change of siltation pattern in the horizontal and vertical section,the amount of siltation in the reservoir and the change of reservoir capacity.The results show that the variation of the water level of the river cross section is basically consistent with the setting requirements of the operating conditions.The change of siltation pattern in longitudinal section shows that the siltation of river bed is not serious,and the final siltation elevation of the river bed behind the dam has not reached the floor elevation of the sand drainage tunnel;the scour funnel appears at the dam site,and the river bottom elevation after cross-section deposition is basically the same as the same as that on the deep line;as the year of operation increases,the amount of sediment deposition becomes larger and larger,but the final sediment deposition height does not reach the dead water level elevation of 1770 m,and the available storage capacity is not reduced.