三明市后山冲沟泥石流易发性评价及预报

2019年5月15—17日和6月7—10日三明市区持续强降雨,其中5月16日24 h降雨量为50年一遇,受强降雨影响,市区东侧后山产生大量浅层滑坡,冲沟内松散固体物源增加,后山冲沟山洪暴发;若在100年一遇甚至200年一遇暴雨作用下,冲沟内产生的浅层滑坡数量及能够参与泥石流活动的松散固体物源量都将会大幅度提高,很可能暴发由浅层滑坡诱发的沟谷泥石流.根据直接指标评价法对三明市区后山20条冲沟的泥石流易发程度进行评价:除了碧桂园后山冲沟为不易发外,其余19条冲沟的泥石流易发程度均为轻度易发;通过19条轻度易发泥石流冲沟的地形数据和2019年5—6月两次降雨过程数据,对浅层滑坡诱发沟谷泥石流降雨预报模型进行验证,结果表明模型预报结果与实际相符;并利用该预报模型给出三明后山冲沟泥石流预报临界降雨值,为该区泥石流预测预报和监测预警指标选取提供参考.

Susceptibility assessment and prediction model of gully debris flow in Sanming Houshan

Heavy rainfall continued in Sanming City from May 15-17, and June 7-10, 2019, and the 24-hour rainfall on May 16 was once in 50 years. Affected by the heavy rainfall, a large amount of shallow landslides was generated, loose solid sources increased , and flash floods occurred in the gully of urban houshan basin; if the rainstorm occurs once in 100 years or even 200 years, the number of shallow landslides and the amount of loose solid sources that can participate in debris flow activities will be greatly increased, and it is likely that debris flows caused by shallow landslides will occur. According to the direct index evaluation method,Debris flow susceptibility of 20 gullies was evaluated: except country garden gullies,the debris flow of the remaining 19 gullies is mildly susceptible; Verifying the prediction model of debris flow caused by shallow landslides through 19 gullies topographic data of mildly prone to debris flow and two rainfall process data from May to June 2019, the results show that the model prediction results are consistent with the actual; Using this prediction model, the critical rainfall values of the gully debris flows are given, which provides a reference for the prediction and monitoring of debris flow in this area.