四川省会理地区糯乍沟泥石流特点及其防治

四川省会理地区"8.30"地震震源浅,强度大,诱发了大量滑坡、泥石流等次生山地灾害,潜在危险性大。糯乍沟位于会理县最南端,为金沙江一级支流,由于地震产生大量崩塌、滑坡和岩土体松动,为泥石流暴发提供了丰富的松散固体物质;右支沟流域汇水面积大,为泥石流提供了充足的水源及动力条件。通过文献分析和野外勘查,结果表明,金沙江强烈的深切作用传导进入糯乍沟,进一步加剧沟床下切及溯源侵蚀,使沟内滑坡失去前沿阻力,失稳概率大增;对该沟的危险性及发展趋势进行了评估,建议在上游崩塌滑坡等隐患点修建谷坊、拦砂坝等土木工程,左支沟坡面侵蚀严重区种植水保林,两者有机结合,可有效控制该沟泥石流的发生。

Characteristics and Countermeasures of Nuozha Debris-flow in Huili County,Sichuan Province

With a shallow epicenter and extraordinary intensity,numerous secondary mountain hazards,including landslides and debris-flows,were triggered by the "8·30" earthquake occurred at Huili County,Sichuan Province.Nuozha gully,one of the tributary of Jinsha River,located in the southernmost of Huili County.The gully experienced a large number of rock-falls,landslides and collapsed slopes induced by the earthquake,which offered sufficient loose materials for the debris-flow.Furthermore,the right branch of the gully has a very large catchment area,which provides the energy and water source for possible outburst of debris-flow.Based on historic documents and field scouting,the downward and headwater erosion of Nuozha Gully,enhanced by downward erosion of Jinsha River,were the leading factors for reduced slope front resistance,resulting in unstable slopes and increasing failures in the upstream.The risks and trends of geohazards were assessed for the gully.Geotechnical engineering,including check dams,debris dam,as well as ecological measures like forest planting,were recommended for controlling debris-flow of Nuozha gully.