基于FLO-2D的溃决型泥石流模拟研究

Modeling of dam-breaking debris flow using FLO-2D model

2013年7月10日华溪沟引发降雨量为100年一遇的溃决型泥石流("7.10"泥石流),造成岷江堵塞并形成堰塞湖,造成巨大经济损失和人员伤亡。为了研究溃决型泥石流危险性,探讨不同降雨频率下暴发泥石流的结果,利用FLO-2D软件对华溪沟在不同降雨频率下溃决与非溃决条件进行了数值模拟,并把100年一遇的模拟结果与实际野外调查情况做出对比。结果显示溃决条件下冲出量、堆积范围面积、平均堆积深度比非溃决条件下超出1倍;溃决时冲出量比实际调查值少5.58万m3。数值模拟结果表明模型的误差在允许范围内,模拟结果与原型相比准确度为88.61%,模拟效果较好。溃决型泥石流规模比非溃决时相比甚大,因此在进行灾害防治设计和危险性评价时应特别注意。

On July 10,2013,Huaxi debris flow was caused by a heavy rainfall with 100 years return period.The debris flow of Huaxi Gully was analyzed as a typical dam-breaking debris flow case,which transported a huge volume of sediment to lower stream and blocked the Minjiang River,resulting in huge economic losses and casualties. In order to analyze the hazard of this type debris flow and the runout of debris flow for different rainfall frequency,this paper simulates the dam-break and non-break debris flows of Huaxi Gulley for different return periods by FLO-2D model. Then we use the FLO-2D run-out modeling results for the 100 years frequency to contrast with the field investigation. The results show that the runout volume,area and average depth under dam-breaking are twice as much as that under non-breaking scenario. The accumulation volume under dam-break is 5. 58 × 104m^3 less than the actual survey. The accuracy of simulation results is 88. 61%,which indicate that a good result to simulate debris flow could be simulated by FLO-2D.