金沙江上游特米大型古滑坡成因及稳定性研究

发布时间：2018-05-19 04:13

本文选题：金沙江上游 + 古滑坡　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：金沙江上游河段地形落差大、水力资源丰富,规划建造多座大型水电站,是我国水电站分布较集中地区。区域内分布有大量古滑坡,其中多数沿金沙江分布。开展古滑坡的形成时期、成因机制等的研究,对区域内水利工程的建设至关重要。大型古滑坡与古地震往往存在一定的相关性,利用古滑坡对古地震参数进行反演是获取古地震参数的有效途径,为现今地震危险性评估和大型工程建设提供参考依据。由于水库建成蓄水后水位上升,古滑坡残留堆积体稳定性降低,对滑坡残留堆积体进行稳定性评价成为水库建设的迫切性问题。特米古滑坡位于金沙江上游四川巴塘和西藏芒康交界河段,是金沙江上游河段分布的众多古滑坡中较为典型的古滑坡之一,距巴塘县城约12 km,滑坡规模巨大。本文在详细的野外地质调查基础上,综合运用遥感解译、室内实验、数值模拟、类比分析等手段,对特米滑坡的成因机制、诱发其发生的古地震参数、残留堆积体在不同工况下稳定性等进行研究。论文取得了如下认识与成果:(1)特米滑坡为大型岩质古滑坡,发生时间约7 200 BP,巨大的滑坡体堰塞金沙江后形成大面积堰塞湖,滑坡体积约为2 110×104 m3,现阶段为残留滑坡堆积体,包括左岸残留堆积体和右岸残留堆积体两部分。(2)原始斜坡稳定性受控于区域内特殊的地质环境条件,地震作用是其发生的触发因素。触发其发生的地震震级为7.0-7.6级,震中距8-30 km,震中位于雄松-苏哇龙段裂上,大致位于特米滑坡下游金沙江沿岸水磨沟到基里一带。(3)特米滑坡发生并堰塞金沙江过程分为以下5个阶段:①地震作用斜坡岩体松动→②后缘拉裂、前缘剪切→③高速下滑→④前缘越过河床、冲向对岸受阻爬高→⑤坡体物质堆积并堰塞金沙江。(4)现阶段特米滑坡残留堆积体在自然工况和地震工况(本文数值模拟所使用地震强度,下同)下处于稳定状态。巴塘水电站建成并达到正常蓄水水位后,在自然工况下可能会发生局部失稳;地震工况下,堆积体前缘会发生失稳破坏,但堆积体不会整体失稳。为保证巴塘水电站的顺利建设以及正常运营,需要对特米滑坡残留堆积体采取一定治理措施。
[Abstract]:The upper reaches of Jinsha River are characterized by large topographic difference and abundant hydraulic resources. Many large hydropower stations are planned and built in China, which is a concentrated area of hydropower stations in China. There are a large number of paleo-landslides in the area, most of which are distributed along the Jinsha River. It is very important for the construction of water conservancy projects in the region to carry out the research on the forming period and the mechanism of the ancient landslide. There is a certain correlation between large ancient landslides and ancient earthquakes. Inversion of ancient seismic parameters with ancient landslides is an effective way to obtain paleoseismic parameters, which provides a reference for seismic risk assessment and large-scale engineering construction. As the water level rises after the reservoir is built and impounded, the stability of the ancient landslide remains is reduced, so it is urgent to evaluate the stability of the landslide residual accumulation. Temigu landslide is located at the junction of Batang, Sichuan, and Mangkang, Tibet, in the upper reaches of Jinsha River. It is one of the typical ancient landslides in the upper reaches of Jinsha River, about 12 km away from the city of Batang County. The landslide scale is huge. On the basis of detailed field geological survey, this paper synthetically uses remote sensing interpretation, laboratory experiments, numerical simulation, analogy analysis and so on, to analyze the origin mechanism of Termi landslide and to induce its paleoseismic parameters. The stability of residual deposits under different working conditions was studied. The results of this paper are as follows: (1) Themi landslide is a large ancient rock landslide with a time of about 7 200 BP, and a large area of barrier lake is formed after the huge landslide Weir plugs the Jinsha River. The volume of the landslide is about 2 110 脳 10 4 m 3. At the present stage, it is an accumulation of residual landslide. The stability of the original slope is controlled by the special geological conditions in the region, and the earthquake is the trigger factor. The magnitude of the earthquake that triggered the event was 7.0-7.6, with a epicentral distance of 8-30 km. The epicenter was located on a crack in the Xiongsong-Suwalong section. The process of Temi landslide is divided into five stages, I. e., the following five stages: the rock mass is loosened and cracked in the rear margin of the slope caused by the earthquake in the following five stages, I. e., the lower reaches of the Temi landslide, along the coast of the Jinsha River from the Shuimogou to the Jiali area. The front edge shearing 3 high speed glide and 4 front edge cross the riverbed, At this stage, the residual accumulations of TMI landslide are in stable state under the natural and seismic conditions (the earthquake intensity used in the numerical simulation in this paper is the same). After the Batang Hydropower Station is built and reaches the normal water level, the local instability may occur under the natural condition, and under the earthquake condition, the front edge of the accumulation body will lose stability, but the accumulation body will not be unstable as a whole. In order to ensure the smooth construction and normal operation of Batang Hydropower Station, it is necessary to take some measures to control the residual accumulation body of TMI landslide.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.22

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