四川都江堰龙池“8.13”八一沟大型泥石流灾害研究

2010年8月13日都江堰龙池八一沟在强降雨(75 mm/h)下导致强大雨水启动沟道及两侧松散堆积物后,冲毁各支沟内的拦挡坝,最终溃决形成规模巨大的过渡性泥石流。在八一沟大型泥石流灾害现场调查的基础上,首先对形成泥石流的地形、水源、物源3个基本条件进行了论述;其次分析了八一沟泥石流的特征和成因;再次计算了泥石流的动静力学参数:容重1.88 g.cm-3左右,泥石流的洪峰流量达1 082 m3.s-1,泥石流的屈服应力在6 700 Pa以上,一次泥石流固体总量为116×104m3,堆积扇上巨石的冲击力为2 449 t;最后分析了泥石流的发展趋势:八一沟流域内还存在大量崩滑体及沟道松散堆积体,在强降雨作用下,很容易再次启动,形成泥石流,造成灾害。

Research On The Disaster Of Debris Flow Of Bayi Gully,Longchi,Dujiangyan On August 13,2010

Based on field investigation and analysis,the formation conditions of the debris flow occurred in Bayi Gully,LongChi,Dujiangyan,like topography,water source and sediment source,were analyzed.The characteristics and formation of debris flow were elaborated and dynamic parameters were calculated,which were the density of 1.88 g·cm-3,discharge of 1 082 m3·s-1,and yield stress of debris flows more than 6 700 Pa.The total volume of sediment in debris flows were estimated at 116×104 m3,the large boulder involving in debris flows in depositional fans have powerful impact force.Finally,the development trend of the debris flow was predicted.Because there are a lot of collapse and landslide in the drainage basins,so it have maximum possibility of happening large-scale debris flow in continuous heavy rainfall.