天然河道水面线计算的几种方法探讨

摘要：介绍了明渠恒定均匀流法、天然河道水面线系统、HEC-RAS软件及SOBEK软件4种常用的水面线推算方法，并对不同河道进行了水面线推算，然后对计算结果进行了对比分析。结果表明：对于坡度较小且沿程顺直、断面规整的河道，若下游起始水位对上游河道水位影响较小，则可用明渠恒定均匀流法进行水面线推算；若下游起始水位对上游河道水位影响较大，则可采用天然河道水面线系统进行水面线推算；对于断面不规整的缓流河道，水位推算结果大体呈天然河道水面线系统、HEC-RAS软件、SOBEK软件的趋势；对于急流河道，HEC-RAS软件推算的水位比SOBEK软件推算的水位偏高。

关键词：明渠恒定均匀流法；天然河道水面线系统；HEC-RAS软件；SOBEK软件；水面线推算

Abstract: nullah constant uniform flow method, four kinds of water lines in the natural channel surface line system, HEC-RAS software and SOBEK software projection methods, and different river water surface line projections, then the calculation results of the comparative analysis. The results show that: if the downstream starting water level on the upstream river water level downstream starting water level For a slope smaller and straight along regular cross-section of the river, upstream water level of rivers, the available the nullah constant uniform flow method, the water line projections; greater impact, you can use the natural channel surface line system for the water line projections; sectional irregular slow flow of the river, the water level projection results in a substantially natural channel surface line> HEC-RAS software> SOBEK software trend; rapids river HEC-RAS software projected water level than SOBEK software projected high water level.Keywords: nullah constant uniform flow method; natural channel surface line system; HEC-RAS software; SOBEK software; surface line projections

前言

水面线推算是河道整治的基础工作，其推算结果直接影响到河道断面的规划设计，进而影响到河道整治的工程量和工程造价。按照弗劳德数(Fr)的不同，河道水流流态可分为三类：缓流(Fr1)和临界流(Fr=1)。平原河道水流一般为缓流，山区河道水流一般为急流，临界流只存在于局部河段。不同的流态有不同的水面线算法，开展不同条件下河道水面线计算方法的应用研究，对于河道水面线推算方法的合理选用、提高设计人员的工作效率都有很重要的作用。笔者对河道整治中经常采用的几种水面线推算方法进行了分析。

1 水面线推算的几种常用方法

1．1 明渠恒定均匀流法