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“5·12”汶川地震导致唐家山高速滑坡堵江,形成唐家山堰塞湖.经过6月10日正常泄流后,堰塞坝体右岸还存在唐家山残留山体稳定性以及附近大水沟、小水沟泥石流等潜在危害.现场实地调查显示,受地震影响,大水沟、小水沟及无名沟沟域内崩塌和滑坡发育,形成了极为丰富的松散物源,具备发生坡面和沟谷泥石流的所有条件,也成为唐家山堰塞湖成功泄水后,仍对堰塞湖正常利用起控制作用的严重地质灾害隐患点之一,“6·14”和“9·24”2次大规模泥石流又导致通口河分别堵江断流4和17h.在查明唐家山堰塞体右岸3条冲沟内松散物源分布及稳定性的基础上,重点结合“9·24”泥石流发育状况,对大水沟、小水沟和无名沟泥石流的发育特征及其动力学特性,尤其是在不同降雨频率下一次冲出泥石流时唐家山堰塞坝体泄水槽的堵江状况及溃决模式进行了系统分析.分析结果表明:3条冲沟形成泥石流堵江后,一次全溃决的可能性很小,其溃决模式为“扇缘部位首先过流→水流挤压左岸并淘刷左岸堰塞体→逐级冲开堆积扇”.这一模式对震后地震灾区泥石流的研究具有指导和借鉴意义.
After Wenchuan earthquake caused the Tangjiashan high-speed landslide to block up the river and form the Tangjiashan dammed lake, after the normal drainage on June 10, the stability of the residual hill body of the Tangjiashan remained and the nearby large Ditches and small gully debris flow etc. The field survey shows that due to the earthquake, the collapse and landslide development in Dashuogou, Xiaanshuiou and Anonymous Gully areas formed a very rich source of loose material, with the occurrence of slope And gully debris flow all conditions, but also become a Tangjiashan barrier lake after the successful drainage, still on the normal use of dammed lake play a controlling role in the serious geological hazards one of the hidden points, “6 · 14” and “9 · 24 ”2 large-scale debris flow led to Tonghe River blocking the river flow 4 and 17h respectively.On the basis of ascertaining the distribution and stability of loose material sources in the right gully of Tangjiashan weir, “9 · 24” debris flow development status, development characteristics and dynamic characteristics of Dashuogou, Xiaoshuiou and Wuzigou debris flow, especially at the different rainfall frequency out of the debris flow Tangjianshan dam body discharge The situation of the water blockage and the pattern of collapse are analyzed systematically : 3 gully debris flow debris flow blocking the river, the possibility of a total collapse is very small, the collapse mode is “fan edge parts of the first flow over the left squeeze the flow of water and scour the left bank barrier body → step by step open accumulation Fan. ”This model is of guidance and reference for the study of debris flow in post-earthquake earthquake-stricken areas.