人工坝溃决洪水峰顶流量计算公式应用于滑坡堵江坝的可行性探讨

Discussion on the Possibility of Applying Peak Discharge Computation of Outburst Flood for Man-made Dams to Natural Dams

滑坡堵江事件在山区广泛发育,堵江形成的天然坝的稳定性一般不高,在暴雨、地震等诱发因素的作用下可能发生溃决,溃坝洪水对下游河道及沿江两岸的各种设施及居民生命造成巨大威胁,因此溃坝洪水计算意义重大,而峰顶流量和洪水演进过程中洪峰高度的变化直接决定了溃坝洪水的灾害程度。利用谢任之教授提出的人工坝溃决洪水计算方法,根据滑坡天然坝体溃决的实际情况,合理地分析溃口形态,调整了溃口宽度的取值方法,并将其应用于滑坡堵江天然坝瞬时溃决洪水峰顶流量计算中,经历史溃坝实例验证计算结果可靠,为天然坝溃决洪水峰顶流量计算提供了新的思路和方法,也为溃坝洪水灾害评价提供了重要依据。

Landslide damming of river is very common in mountainous regions, and the stability coefficients of natural dams are rather low, so they are prone to break under the induction of rainstorm, earthquake and other factors. The successive outburst flood will destroy all sorts of installations, even seriously threaten the safety of residents in downstream watercourse and banks, so it is of great significance to carry out outburst flood computation. Among those factors which affect the degree of flood disaster, peak discharge and flood peak are two important index. In this paper, peak discharge under the case of instantaneous break of natural dam is discussed taking advantage of computation method of man-made dam proposed by Prof. Xie Renzhi. Based on the actual breach condition of natural dam, the shape of break section is reasonably analyzed, the width of break section in computation formula is modified. The result is proved to be reliable by survey of dam breach flood in history. All these provide a new way for outburst flood calculation and also provide theoretical foundation for outburst flood disaster evaluation of natural dams.