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金沙江上游新构造运动活跃,崩塌、滑坡、堰塞湖等地质灾害广泛发育,是古、今堰塞湖多发的地区.以金沙江上游雪隆囊大型古滑坡堰塞湖溃坝堆积物为例,对溃坝堆积物的粒度特征及其与沉积环境的关系进行了研究.并对雪隆囊滑坡堰塞湖溃坝堆积物的粒度进行了测试.结果表明:1)从溃坝堆积体的上段→中段→下段,粒度频率曲线分别为单峰、多峰、双峰,粒径有明显的细化趋势(粗→细);2)溃坝堆积物的分选系数从上段→中段→下段依次减小,表明分选性逐渐变好;3)溃坝堆积物的粒度累积曲线上游段为两段式,中、下游段为三段式,水动力条件从上段→中段→下段依次减弱.以上这些特点综合反映了该研究区内水动力条件由溃坝堆积体上游到下游在逐渐减弱.
Jinsha River upstream of the new tectonic activity is active, collapse, landslides, dammed lake and other geological disasters, extensive development, is the ancient, nowadays dammed lake prone area.A large ancient landslide in the Jinsha River large ancient landslide barrier dam lake deposits In this paper, the grain size characteristics of the dam-breached dam and its relationship with sedimentary environment were studied, and the grain size of the dam-damaged sediment in the Sebu-Sheng Lake was tested. The results show that: 1) The upper part → the middle part → the lower part, the granularity frequency curves are unimodal, multimodal and bimodal, and the particle size has obvious thinning tendency (coarse → thin); 2) 3) The upstream section of the grain-size accumulation curve of the dam-damaged sediment is of two-stage type, the middle and lower reaches are three-stage, and the hydrodynamic conditions are weakened from the upper section to the middle section to the lower section These above characteristics reflect that the hydrodynamic conditions in this study area are gradually weakened from upstream to downstream of the dam body.