金沙江上游雪隆囊古滑坡堰塞湖溃坝堆积物粒度分维特征分析

Analysis of grain size fractal feature of outburst deposits induced by the Xuelongnang Paleolandslide-Dammed lake in the upper Jinsha River

本文依据分形理论,以金沙江上游雪隆囊古滑坡堰塞湖溃坝堆积物为研究对象,对其粒度分维特征进行研究。研究结果表明:溃坝堆积物具有很好的统计自相似性,随着采样区空间位置的不同,其粒度分维值的大小也有明显的变化,即上游段粒度分维平均值为2.52,中游段粒度分维平均值为2.28,下游段粒度分维平均值为2.06。且粒度分维值的大小与分选性的好坏密切相关,分选系数大则分维值大,反之,分维值则小。粒度分维与粒度分布以及粒度的粗细也有一定的内在关系,粒度分维值D既能够反映研究区溃坝堆积物粒度的分布也能够反映其溃坝堆积物颗粒的粗细。

The paper based on Fractal theory,taking the Jinsha River tour the ancient landslide dam Xuelongnang capsule deposits as the research object,research on the fractal dimension of its grain size. Research results show that： dam break deposit has good statistical self similarity,with the sampling area of the space location,the size of the fractal demension value is also significantly changed,that is,the average fractal demension of the upstream segment is 2. 52,the average fractal demension of the midstream segment is 2. 28,the average fractal demension of the downstream segment is 2. 06. The value of the fractal dimension is closely related to the size of the separation,the separation coefficient is large,and the fractal dimension is large,on the other hand,the fractal dimension is small. The granularity of the fractal demension and the size distribution of grain size and the thickness of the grain size also have some intrinsic relationship,the grain size fractal dimension value D can reflect the distribution of the dam break and the thickness of the particles in the dam break.