四川汶川县映秀镇红椿沟“8.14”特大泥石流形成条件与运动特征分析

Formation conditions and the movement characteristics of “8.14” giant debris flow in Yingxiu Town,Wenchuan County,Sichuan province

2010年8月14日,汶川县映秀镇强降雨导致红椿沟暴发特大泥石流灾害,冲出固体物质80.5×104m3,泥石流堰塞堵断岷江主河道,导致河水改道冲入映秀新区,淤埋了沟口213国道公路400m,掩埋了在建映(秀)-汶(川)高速公路引线路基及多个桥墩,造成17人失踪。据灾后调查,红椿沟泥石流为近几年暴发的较典型泥石流沟,地震诱发的集中物源特别丰富,暴发泥石流时一次冲出固体物质量巨大,沟内多点堵溃、拉槽下切集中启动物源的特征十分明显;本文重点分析了形成泥石流的三大条件及泥石流启动机理,反算运动特征参数,预测其发展趋势。

A rainstorm triggered debris flow hazard occurred in Hongchun valley, Yingxiu town on August 14,2010. This event transported 805,000 m3 material sediment to the watercourse of the Minjiang River and produced a natural dam,resulting in a flash flood in the new Yingxiu town. It buried the national highway 213 out of the vallay for 400m and the roadbed and many piers of the Yingxiu-Wenchuan road that wad on building. 17 people were missing. The Hongchun vallay debris flow was one of the typical debris flow gullies occurred in the last years according to the survey after the hazard. The centralized provenance was particularly rich after the earthquake, the flow solid matter volume was huge once as the debris flows in progress and the character of multi-point dam-breaking and pull trough incised to start the provenance was very obvious, what was found in the survey. This paper is selective analysis. The three conditions for the formation of debris flow debris flow movement mechanism is analyzed and the motion characteristic parameters is inversed,forecasting the trend of its development.