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汶川地震后,由地震引起的堰塞体溃决所导致的溃决型泥石流频繁发生,其规模和危害程度远超非溃决型泥石流。为了预测溃决型泥石流冲出特征值与威胁范围,基于FLO-2D数值模拟,以牛圈沟为例,考虑沟道内堵点溃决,对不同降雨频率下的牛圈沟泥石流进行数值模拟并得到其堆积范围及沿程流速、泥深值。采用泥深及泥深与流速乘积值之间关系的方法进行强度划分后,与暴发的重现周期相互结合进行泥石流危险性评价,以此为牛圈沟防灾减灾提供科学参考。对比牛圈沟“9.26”溃决型泥石流与“8.14”非溃决型泥石流实际情况与模拟结果,进行精度验证,结果显示模拟精度较高,与实际较为接近,同时溃决/非溃决型泥石流的冲出量比值能达2.88倍,因此在灾害防治时需要特别关注溃决型泥石流。
After the Wenchuan earthquake, the collapse-type debris flow caused by the earthquake caused by the damming body frequently occurred, and the scale and harm degree far exceeded the non-collapse debris flow. In order to predict the characteristic and threat range of outburst debris flow, based on FLO-2D numerical simulation and taking Niuogou as an example, considering the blockage in the channel, the numerical simulation of the Niuogou debris flow at different rainfall frequencies Accumulation range and along the flow rate, mud depth value. After the intensity is divided according to the relationship between the depth of mud and the product of mud depth and velocity, the risk of debris flow is evaluated by combining with the recurrence period of outbreak, so as to provide a scientific reference for disaster prevention and mitigation of Niu’ougou. Contrasting the actual situation and the simulation results of the “9.26” ulcer-type debris flow and the non-ulcer-type debris flow in the Bentougou “9.26 ” area, the accuracy verification shows that the simulation accuracy is high, and it is close to the actual value, Debris flow out of the ratio of 2.88 times, so in the disaster prevention and treatment need to pay special attention to the collapse of debris flow.