现行淤地坝设计洪水计算方法的适用性对比分析

Comparative Analysis of Applicability of Current Calculation Methods of Design Flood for Check Dams

[目的]洪水是导致淤地坝水毁最根本的原因,深入探讨淤地坝设计中洪水分析计算方法,以期对其发展提供有益参考。[方法]梳理现行淤地坝设计洪水计算方法,对比分析各种方法的适用特点。对理论性较强的推理公式法在淤地坝设计洪水计算中的适用性进行分析,总结其各类参数的物理意义,提出其运用要点。选取典型算例,研究比较各方法的计算特点及适用性。[结果]洪水调查法可靠可行但受洪水资料条件限制,经验公式精度和应用具有地区局限性,两种方法均不宜较大范围应用;推理公式法具有一定理论基础和计算精度,且简单实用,具体运用中应注意淤地坝处于特小流域的特点,在计算流域特征值L和J时应判明最远流程中的坡面部分,在计算暴雨递减指数n时应选取由10—60 min的点暴雨n_(1)值,产汇流参数中μ偏大,m偏小,应在合理范围内相应的倾斜取值。[结论]推理公式法应当作为淤地坝设计洪水分析计算中的首选方法,需关注淤地坝处于特小流域的特点,把握应用推理公式法的运用要点。

[Objective]Flooding is the most fundamental cause of check dam damage.Discussion regarding the analysis and calculation method used for designing check dams to withstand flood damage was conducted in order to provide a useful reference for further development.[Methods]Current calculation methods for designing check dams to withstand flood damage were reviewed,and the applicable characteristics of various methods were compared and analyzed.The applicability of a theoretically strong reasoning formula method for a flood design calculation applicable to check dams was determined.The physical meanings of various parameters were summarized,and then the main points of their application were put forward.A typical example was selected to study and compare the calculation characteristics and applicability of two methods.[Results]The flood survey method was reliable and feasible,but limited by the conditions of flood data.The accuracy and application of the empirical formula had regional limitations.Neither of the methods were suitable for large-scale application.The reasoning formula method had a certain theoretical basis and calculation accuracy,and was simple and practical to implement.For a specific application,attention should be given to the characteristics of check dams located in very small watersheds.For the calculation of the basin eigenvalues L and J,the part of the slope in the furthest flow should be determined.The value of point rainstorm n_(1) should be selected from the range of 10 minutes to 60 minutes for the calculation of rainstorm decline index n.μwas too large and m was too small for the runoff generation and confluence parameters,and the corresponding slope values should be selected within a reasonable range.[Conclusion]The reasoning formula method should be the preferred method for the analysis and calculation of flood design characteristics for check dams.Attention must be given to the characteristics of check dams located in very small watersheds in order to grasp the key points in applying the reasoning formula method.