泥石流堆积及其对主河河床演变和输沙特征影响的研究已有不少成果问世，但基于实地观测数据的具体演化过程的分析研究还不多见，以2008年至2010年蒋家沟入汇段小江河床地形断面监测和采样分析为基础数据，结合泥石流活动的观测资料，对蒋家沟入汇后泥沙物质的堆积及其再起动输沙特征进行了分析。蒋家沟入汇的泥石流固体物质主要堆积于入汇口以下500 m（主河宽10倍以内）的范围内，堆积量的多少与原堆积物被小江冲刷输移的量有关。泥石流物质在被小江输移的过程中沿途落淤而堵塞河道，常常引起主河小江的改道。泥石流物质的堆积使小江在入汇处形成节点，尽管近年来入汇口附近小江河床总体表现为冲刷的趋势，但下游冲刷速度较上游快，导致下游河床比降增大而上游减小，入汇口的节点特征更为突出。

Despite many research results of debris flow deposit and its influences on the evolution of main river bed and sediment characteristics, analysis on the specific evolution process based on field observational data are rarely seen. Taking the topographic monitoring data of the cross-section and samples of Xiaojiang river reach of the Jiangjia Ravine from 2008 to 2010, in association with the observation data of debris flow, we analyzed the characteristics of deposit and re-start transport of sediment after the Jiangjia Ravine debris flow converged into the main river. Results showed that solid sediment from the debris flow mainly deposited in the range of 500m lower of the confluent entrance (less than 10 times the width of the main river). The amount of the accumulation was related to the amount of the original deposit eroded and transported by the Xiaojiang River. During the transport, the sediment blocked the riverway and frequently changed the route of the main river. Deposit of the debris flow sediment gave rise to nodes at the confluent entrance. Although the riverbed of Xiaojiang River near the confluent entrance exhibited a trend of erosion in recent years, erosion in the downstream was faster than that in the upstream, which led to gradient increase of the riverbed in the downstream whereas decrease in the upstream, showing prominent node features at the confluent entrance. 