【作者】 杨方社；

【导师】 王新宏；

【作者基本信息】 西安理工大学 ， 环境工程， 2004， 硕士

【摘要】 三门峡水库建成以来，潼关高程问题就一直是上下游各方关注的焦点问题，也是一个难点问题。2003年渭河的小水大灾以及近期渭河流域综合治理规划的制定，又一次使潼关高程问题成为各方研究的热点。因此，研究不同潼关高程对渭河下游冲淤及洪水位的影响具有迫切而重要的现实意义。 本文首先对以往的研究成果进行了简要的同顾和评述。然后以实测资料为基础分析研究了三门峡建库前后潼关高程的变化规律以及渭河下游河道的冲淤演变规律，分析研究表明：建库前渭河下游主槽处于动态冲淤平衡状态，滩地处于微淤状态；建库后，渭河下游河道发生严重淤积主要是由于潼关高程的抬升造成的；潼关高程的抬升主要是由于三门峡水库的不合理运用造成的，近期不利的水沙条件加剧了潼关河床的抬升速度和渭河下游的淤积。其次对泥沙沉速计算、水流挟沙力和恢复饱和系数的取值等问题进行了探讨，在此基础上对现有的泥沙数模学型进行了改进和完善。利用1969～2001年的实测资料对模型进行的率定和验证计算结果表明，各河段计算冲淤量与实测值吻合较好。最后用验证后的数学模型对不同水沙系列、不同潼关高程(328m、327m、326m)下渭河下游的冲淤趋势和洪水位的变化进行了预测计算，从定量上回答了潼关高程从328m降至327m(相当于潼关高程降1m)和潼关高程从328m降至326m(相当于潼关高程降2m)时，渭河下游14年之后各河段的减淤程度以及不同流量级洪水位的降低幅度，这些成果对于渭河下游防洪治理规划的制定具有重要的参考价值。更多还原

【Abstract】 A series of problems caused by the increasing riverbed elevation at Tongguan have been concerned by many departments along the upstream and downstream of the Sanmenxia dam since its construction in 1960. Recently, these problems are again concerned because of the planning of the Weihe river basin comprehensive regulation and the catastrophe caused by the small flood on the Weihe river in 2003. Accordingly, it is urgent and important to study the effect of different Tongguan riverbed elevations on aggradation and degradation as well as the flood elevation of the lower Weihe river.Firstly, past and present achievements are briefly reviewed in this paper. Secondly, based on practical field data, it is systematically analyzed and studied that the process and mechanism of Tongguan riverbed elevation as well as aggradation and degradation of the lower Weihe river bed before and after the construction of the Sanmenxia dam. By the analysis and study, it is showed that: 1) the lower Weihe river main channel was at a balanceable state between aggradation and degradation and floodplain of the lower Weihe river is a tiny aggradation state before the construction of the Sanmenxia dam; 2) the severeaggradation of the lower Weihe river bed is mainly caused by the increasing riverbed elevation at Tongguan after the construction of the Sanmenxia dam; 3) the main reason leading to the increasing riverbed elevation at Tongguan is the unreasonable operation of the Sanmenxia reservoir; 4) the rate of the riverbed aggradation at Tongguan reach and the lower Weihe river reach are speeded by adverse condition of incoming water and sediment recently. Thirdly, several problems are discussed, such as the calculation of the silting velocity of sediment, the sediment transport capacity, the coefficient of sediment resume saturation, etc. On the basis of these discussions, the mathematical model is improved. Lastly, the improved mathematical model of sediment transport is tested by practical field data of 1969~2001. It is showed that the calculated volume of silted and scoured sediment is well in accordance with the practical measured volume in the lower Weihe river. Finally, by using of the mathematical model, it is calculated and predicted the effect of the different Tongguan riverbed elevations as well as the different conditions of incoming water and sediment on the variance of the flood elevation and the tend of aggradation and degradation of the lower Weihe river bed. It is answered quantitively the lessening extent of sediment silt and the decreasing extent of the flood elevation of the lower Weihe river after 14 years on two different incoming water and sediment conditions with three different Tongguan elevations, respectively 328m, 327m and 326m. These results supply important references to the planning of flood control and comprehensive regulations of the Weihe river basin.更多还原