通过对2011年7月3日的茂县棉簇沟泥石流灾害的现场调查,从物源、地形和水源条件入手,分析了灾害特征与形成演化过程。强降雨是本次泥石流的诱发因素,沟道内复杂的地形地貌特征为泥石流提供了演化和规模放大条件:(1)泥石流导致堰塞湖溃决,为泥石流提供了近1×104m3的水源,增强了泥石流的水动力条件,增加了沿途冲刷量;(2)沟道内多处基岩卡口和跌水放大了本次泥石流的规模和速度;(3)沿途固体物质补给使泥石流容重逐步增大。此次泥石流造成沟道微地貌改变,今后泥石流暴发的可能性和频率将会大大增加,高频率、中小规模泥石流将是今后该沟泥石流活动的特征。 更多还原
 

The formation and evolvement process of this debris flow was analyzed based on the field investigation on the material sources, rainfall, and topography conditions. The rainfall was the inducing factor; however, the topography in the gully was the main reason which causes this catastrophic debris flow: (1) the dammed lakes formed in the earthquake were broken which increased the water supply, strengthened the dynamic force, and aggravated the erosion quantity finally. (2) the narrow sections and the drops amplified thepeak flow and velocity of the debris flow in the gully. (3) the solid material supplies the debris flow and enlarged the density along thegully. The possibility and frequency of debris flow will be much higher in heavy rainfalls in the future, but the scale will be less than thisgiant debris flow because of the microtopography had been changing. Suggestions were proposed: the warning system, control engineering should be built and disaster prevention and reduction awareness of local people also should be improved.