黄河万家寨水库上游段水动力特性研究

为深入研究万家寨水库上游河段冰期的冰情特征与演变规律,并为该河段的防凌减灾工作提供科学依据,依据实测的水位、流量、河道地形资料,通过HEC-RAS软件建立黄河干流万家寨水库上游坝址至头道拐段的水动力模型,模拟研究河段2013年4月—2014年3月的水动力变化过程,探究各典型时期水动力参数的时空分布特性。结果表明:(1)基于实测水位数据对模拟结果进行对比验证,模拟水位与实测水位的相对误差13%,吻合度较高,可以较好地模拟研究河段的水力要素随时间、空间的演变过程。(2)研究区域枯水期、汛期、流凌期、开河期模拟水位空间分布存在差异性。结合流量特征分析,各典型时期上下游河段的水位差与流量呈正相关关系。(3)通过分析各典型断面处的水深和流速变化过程,曹家湾河段在冰期易卡冰结坝、诱发冰凌灾害的主要原因为:该河段过水断面相对较小且水流经过此处流速明显降低。

Hydrodynamic characteristics upstream of Wanjiazhai Dam in the Yellow River during freezing period

In order to provide a scientific basis for preventing and reducing ice flood disasters upstream of Wanjiazhai Dam, the hydrodynamic characteristics and evolution of ice regime has been studied based on the measured data of water level,flow and river topography by using the HEC-RAS. The hydrodynamic process was simulated and the hydrodynamic parameters were given in typical periods in the reach of the Yellow River from Wanjiazhai to Toudaoguai from April 2013 to March 2014. The following conclusions are drawn on the basis of this study:(1) The relative error of the simulated water level with the measured water level is less than 13%, which shows that the method is feasible to simulate the spatial and temporal evolution of hydraulic factors in freezing period. (2) There are differences in the spatial distribution of the water levels at this reach in dry periods, flood periods, ice-flowing periods and break-up periods, and there are positive correlation between the flood peaks and flows of upstream-downstream combining with the characteristics of flows. (3) Through analyzing the process of water depth and flow velocity at the typical sections, it is found that the Section of Caojiawan is prone to form ice jams and cause ice disasters because of the smaller sectional area and lower flow velocity.