理县打色尔沟泥石流演化历史及危险性评价

发布时间：2018-03-23 12:15

  本文选题：打色尔沟泥石流　切入点：演化历史　出处：《成都理工大学》2015年硕士论文

【摘要】：由于对泥石流活动规律认识的不足,加之西南山区受地形地势影响,人们常在一些地势比较开阔的老泥石流堆积扇上兴建城镇或工厂,泥石流复活后冲毁建筑物,填埋厂矿,往往造成惨重损失。而人口密集的理县老县城正是建设在打色尔沟沟口大规模多期次的古泥石流堆积扇上,若暴发类似历史规模的泥石流,后果不堪设想。泥石流演化历史的研究对岷江上游泥石流演化和现代泥石流分析有一定参考作用。而打色尔沟是否会发生历史规模大小的泥石流又是一个极具现实意义的重要的问题。本文在收集整理基础地质资料的基础上,对打色尔沟古泥石流堆积状况及震后泥石流状况进行调研,分析古泥石流的演化及现代泥石流的形成条件,用单沟泥石流评价模型对打色尔沟泥石流进行评价并预测未来泥石流规模。取得了如下主要成果:(1)对打色尔沟沟口古泥石流堆积体进行详细调查,从老到新做出Ⅶ期分期,并对各期次泥石流细部特征进行分析。古泥石流和川西高原构造运动存在一定对应关系,古泥石流堆积体中第Ⅳ、Ⅵ、Ⅶ期次分别与200ka BP、30-50ka BP、10ka BP川西高原新构造运动相对应。气候方面,理县黄土、冰川等分别揭示了气候变迁对古泥石流形成、变化的影响。(2)从演化历史角度预测打色尔沟泥石流未来发展规模:古泥石流受构造运动及冰期作用明显,但随着杂谷脑冰川的后退和川西高原构造运动的稳定,无法提供超过古泥石流发生时的水源和构造运动时大量的松散物质,因此打色尔沟泥石流未来发生的规模不会超过古泥石流规模。打色尔沟泥石流将从冰川泥石流转为暴雨型泥石流。(3)打色尔沟“7.6泥石流”是一次低频、特大、暴雨沟谷型泥石流,现在泥石流发展阶段为发展期。发育特征方面:打色尔沟沟道长,沟道宽窄相间,冲淤相间或叠加,泥石流堆积以沟道堆积为主。流域内松散固体物源较丰富,累计出沟量所占比例小,物源储备量仍很大。(4)采用刘希林单沟泥石流评价模型对打色尔沟泥石流危险性进行评价,评价结果是打色尔沟泥石流主沟和1#支沟、3#支沟、4#支沟为中度危险,6#支沟为高度危险。与理县泥石流危险区划的应用结果:理县泥石流危险度为0.6034,为Ⅲ级危险区(即显著危险)相一致。(5)通过物源估计法和雨洪法预测打色尔沟泥石流未来发生的规模,综合两种方法,预测的结果为主沟:3.775万方;1#:1.05万方;3#:1.335万方;4#:0.505万方;6#:1.32万方。
[Abstract]:As a result of the lack of understanding of the law of debris flow activities and the influence of topography on the mountainous areas of southwest China, people often build towns or factories on the old debris flow accumulation fans with relatively open terrain. After the debris flow is revived, buildings are destroyed and factories and mines are buried. Often causing heavy losses. And the old county town of Lixian, densely populated, is built on a massive and multi-stage ancient debris flow accumulation fan at the mouth of the Tasiergou gully. If a debris flow of a similar historical scale breaks out, The study of debris flow evolution history has certain reference value for debris flow evolution and modern debris flow analysis in the upper reaches of Minjiang River. On the basis of collecting and sorting basic geological data, The accumulation status of ancient debris flow in Tasiergou and the condition of debris flow after earthquake were investigated, and the evolution of ancient debris flow and the forming conditions of modern debris flow were analyzed. The single gully debris flow evaluation model is used to evaluate the debris flow and predict the scale of the debris flow in the future. The main achievements are as follows: 1) A detailed investigation of the ancient debris flow accumulation at the mouth of the Dasergou gully has been carried out, and from the old to the new stage 鈪，

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