中文摘要：

李子凹沟和滑脚坡沟是著名高频泥石流沟蒋家沟中游流通段的两条支沟,流域条件极为相似,泥石流暴发频率高,堆积扇发育快。以这两条沟为对象,观察泥石流在堆积扇上的运动和停积过程,对不同特征的泥石流堆积体进行采样分析,并在每年雨季前后测量堆积扇地形及其纵横断面。对这两条支沟泥石流堆积扇2006～2008年的发育过程、平面形态、纵横剖面、堆积速度等进行分析,得出如下结论：（1）滑脚坡沟泥石流体颗粒较粗,容重大,泥石流整体堆积,呈垄岗状。李子凹沟泥石流粗大颗粒少,容重小,在扇体上漫流,堆积呈舌状。堆积扇的进一步发育主要靠垄岗状堆积-改道完成。（2）主沟堆积条件下,支沟泥石流堆积扇以淤高为主,且淤高幅度在扇体上下部分布均匀。（3）泥石流堆积扇发展到一定程度后,纵比降基本稳定,表现为剖面上发生持续且较为均衡的堆积。横剖面在主沟上游方向的坡度较小。

英文摘要：

The Liziwa Ditch and Huajiaopo Ditch are 2 tributary ditches in middle reaches of the Jiangjia Ditch,a famous ditch having debris flow of high frequency.These two ditches are extremely similar in conditions of drainage area,with high frequency of outbreaks of debris flow and rapid development of deposit fan.These two ditches were studied in this paper,process of movement,ceasing and accumulation of debris flow on deposit fan were observed,deposit body of debris flow with different features were sampled and analyzed,and terrain of deposit fan was measured before and after rainy season annually as well as its vertical and lateral section.By analysis of development process,planar shape,longitudinal and transverse section,accumulation rate of deposit fan in the 2 tributary ditches during 2006~2008,the following conclusions were obtained.Huajiaopo Ditch was larger in volume weight and grain size,and its accumulation was holistic and Lung Kong-shaped.Whereas Liziwa Ditch was smaller in volume weight and grain size,and debris flow overflowed on deposit fan and its accumulation was linguiform.Further development of deposit fan was completed by Lung Kong-shaped accumulation-course changing.On accumulation condition of the main channel,deposit fan in tributary ditch had mainly accretion,and extent of accretion was uniformly distributed at top and bottom of the fan.When debris flow fan developed to a certain extent,its vertical gradient was stable and smaller cross slope showed at the upstream direction of the trunk channel.