公路黄土坝式路堤汛限水位及涵洞泄洪力设计计算方法

为了构建简单易行且符合实际设计需要的公路黄土坝式路堤汛限水位及涵洞泄洪力计算方法，在已有坝式路堤水位研究成果的基础上，利用其合理的水量平衡原理及水位关系理论，分析归纳出理想均值水位和汛限水位的方法理论基础；同时为避免不合理的具体库型对坝式路堤的影响，引入水利方面处理库型的方法，利用蒸发渗流理论得到水位与总损失量关系曲线以确定理想均值水位，再借鉴水利方面测量库容方法构建水位库容关系曲线，继而确定汛限水位，从而构建得出设计需要的坝式路堤汛限水位及涵洞泄洪力计算方法步骤。最后采用已建的坝式路堤对该计算方法进行验证，并与已有文献进行对比分析。结果表明：坝式路堤涵洞设计方法套用现行公路手册是不合适的，与实际情况不符，即绝大多数坝式路堤不需要设计涵洞，提出了构建水位-总损失率关系曲线以确定理想均值水位，构建水位-库容关系曲线以确定汛限水位，利用调洪公式进行涵洞设置与否及泄洪力设计的三步骤设计法；在水量平衡原理和已有研究成果基础上，引入水利方面处理库型库容方法能避免库型影响，使库容测量能够切实可行；构建的设计计算方法用于天巉线K168＋740～K168+880坝式路堤时，得出的汛限水位为16.60 m，路堤历史最高水位为15.47 m，汛限水位偏大，该方法用于实际工程设计时偏于保守。所构建的方法可为公路坝式路堤设计、水利淤地坝设计提供借鉴。

Design and Calculation Method of Highway Loess Dam-like Embankment Flood Limit Level and Culvert Flood Discharge Capacity

The objective of this study is to obtain a simple calculation method for the highway loess dam-like embankment flood limit level and culvert flood discharge capacity. Based on the existing research results of the water level of the dam-like embankment, the principle of water balance and water level relation theory are used to analyze and summarize the theoretical basis of the ideal average water level and flood limit level. To prevent the effect of unreasonable and specific reservoir types on the dam-like embankment, the relation curve of the water level and total loss is obtained by combining the method of hydraulic engineering treatment and theory of evaporation seepage to determine the ideal mean water level. Subsequently, the measurement methods of reservoir capacity in hydraulic engineering are used to determine the relation curve of water level and reservoir capacity. Consequently, we can formulate the calculation method for the dam-like embankment flood limit level and culvert flood discharge capacity. A built dam-like embankment is used to validate the calculation method, and the existing literature is compared and analyzed. The results show that the design of the culvert of the dam-like embankment is not suitable when the current road manual is directly copied, which is not consistent with the actual situation. Thus, most of the dam-like embankments do not need designing of culverts. The three steps of the design method proposed in this paper are:"set up the relationship curve of the water level and total loss rate to determine the ideal mean water level", "set up the relationship curve of the water level and reservoir capacity to determine the limited water level", and "use the formula of flood regulation to determine whether the culvert is set up or not and obtain the design flood discharge capacity". Based on the principle of water balance and the existing research results, a method for dealing with the reservoir types and capacity in hydraulic engineering is introduced. This method can avoid the influence of the reservoir types and make the measurement of the reservoir capacity practical and feasible. When the obtained design calculation method is applied to Tianchan line K168+740-880 dam-like embankment, the flood limit level is 16.60 m, whereas the highest level in the history of embankment is 15.47 m. When the method is applied to practical engineering design, the obtained flood limit level is slightly larger and conservative. The method proposed in this paper can be used for reference in highway dam-like embankment design and check dam in hydraulic engineering design.