大渡河上游干桥沟泥石流发育特征与防治方法

通过野外调查与实地勘测，在查明泥石流的形成背景条件及灾害特征的基础上，分析了干桥沟暴发大规模泥石流灾害的成因，计算了泥石流运动特征参数，探索了泥石流沿沟道的演化过程及机理，提出了相应防治方法。研究结果表明:干桥沟为高频大规模泥石流，具有暴发频率高、成灾速度快、运动过程短、危害严重的特点；受沟道微地貌影响，泥石流沿沟道演化过程具有“小淤大冲、聚小成大”的特征，是形成大规模泥石流灾害的主控因素；受物源点活动趋势的控制，干桥沟常态工况下的泥石流的暴发规模和频率呈降低趋势，对沟口危害较小，但受泥石流聚小成大的演化规律影响，在极端暴雨工况下将暴发大规模以上灾害，危害县城安全。针对泥石流特征，提出“以固源、稳沟、拦挡为主，辅以消能、排导”的治理方法；同时对白呷衣滑坡变形进行监测，加强泥石流灾害的预警。

Characteristics and Countermeasures of Debris Flow of Ganqiao Gully in the Upper Dadu River

Based on investigation of the formation conditions and activity characteristics of debris flow by surveys, researches were conducted to examine the hazard causes and the motion parameters, and countermeasures for debris flow mitigation were also proposed. Analysis suggested that debris flows were characterized by high frequency, high speed, short process, large-size and severe risks. And the scale of disaster was influenced by microtopography of the gully. In normal situation, the frequencies and scales of debris flows can decrease gradually in Ganqiao gully, but, because of the evolutionary process which can amplify the scale of debris flow, large-size disaster can occur. In order to mitigate this debris flow, the countermeasures such as building check dams, channel, and warning system of Baigayi landslide wear put forward in this paper.