基于桥墩水痕与等流时线法的桥梁水害预警

针对现行中小流域桥梁水害预测方法存在误差大,外业强度大,缺乏水文资料难预测及重结果不重过程等弊端,提出一种用历史桥墩水痕推求流域概化汇流曲线的新方法,预测桥位断面洪峰流量大小的同时,对洪峰流量抵达桥下的具体时间进行了预测。为弥补等流时线法固有缺陷,采用下游流域面雨量过程作为实测降雨过程来对桥位断面汇流过程进行计算,利用洪峰流量减小系数和洪峰时间延迟系数来考虑河槽调蓄对洪峰流量大小以及抵达桥下时间的影响。实例证明,该法具有较高的精度,能够满足实际生产的需要,减少了野外勘测的工作量,使洪水预警工作变得更加简单和有效。

Water Hazard Early-warning of Bridge Based on Pier Water Mark and Isochronal Method

According to the drawbacks of existing water hazard prediction methods for small and medium bridges,such as big error,large outwork strength,difficult prediction with little hydrographic information,only emphasizing results and so on,this paper presented a new method to deduce the generalized conflux curve of the river basin by the historical pier water mark,which can not only predict the flood peak discharge but also the specific time when the flood peak reach the bridge.In order to remedy the defect of the isochronal method,this paper used the precipitation process of the lower basin area as the measured precipitation process to speculate the flood hydrograph caused by the rainstorm and applied peak discharge reduction coefficient and peak time delay coefficient to survey the influence of adjusting channel storage.The method presented in this paper has proved of high accuracy by practice and can meet actual production needs,which can greatly reduce the field work amount and simplify the flood prediction process so as to improve work efficiency.