IMHE OpenIR  > 山地灾害与地表过程重点实验室
帕隆藏布流域冰碛土体起动泥石流力学机理试验研究
Alternative TitleExperimental Study on Mechnism of Moraine Soil Triggering Debris Flow in Palongzangbu Basin
朱云华
Subtype博士
Thesis Advisor陈宁生
2017
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline岩土工程
Keyword冰碛土体 泥石流 力学机理 降雨试验 融水试验
Abstract冰碛土在青藏高原的分布广、储量大,因冰川融雪或降雨引起的冰碛土体失稳起动泥石流灾害时有发生,对我国的社会稳定、工程建设及人民的生产生活造成巨大威胁及严重经济损失。目前国内外对冰碛土体起动泥石流的研究较为薄弱,本论文选取帕隆藏布流域的一条侧碛堤坡面作为试验点,进行野外泥石流起动试验,通过比较不同粘粒含量的坡面土体在模拟降雨及融水2种工况条件下的孔隙水压力及含水量的变化曲线,分析冰碛土体起动泥石流的过程及特征,并在蒋家沟野外泥石流起动试验的基础之上,并结合室内试验及分形理论,对冰碛土体起动泥石流的力学机理进行探讨。综合分析后得到以下成果:(1)冰碛土在粒度分布上具有良好分形特征。本文取样的冰碛土粒度分维为2. 044 ~ 2. 674,主要以二重分维为主。细颗粒含量,尤其是粒径小于0.01mm的颗粒含量与土样的粒度分维值较大相关,二者为多项式关系,而起动泥石流的冰碛土体的颗粒粒度分维与小于0.01mm的颗粒含量之间为线性关系。(2)冰碛土中粘粒含量过低时(<0.32%),无论是降水还是融水作用,均不能起动泥石流。坡面泥石流起动以掏蚀+坍塌型为主,对粘粒含量不高于3%的土体来说,大部分发生的是这类泥石流;而当粘粒含量较高时(>3%), 土体发生铲蚀+面蚀型起动。(3)不同水源条件下,冰碛土体起动泥石流的孔压变化形式不同。对于降雨型泥石流来说,土体内孔压值迅速增大,容易造成土体破坏,起动泥石流;而对于融水型泥石流来说,当土体内的孔压值呈小幅波动时,土体也可能发生失稳破坏,起动泥石流。(4)松散砾石土体失稳起动泥石流是孔隙水压力升高,粘滞阻力降低,拖曳力与渗流侵蚀共同作用的结果,其作用分别为26%、46%、7%、21%,而对发生铲蚀+面蚀型起动的冰碛土体来说,其作用比例分别为;16%、45%、6%、32%。(5)对于融水作用下的冰碛土体起动泥石流,是发生的掏蚀+坍塌型起动,其水力坡降增大到临界值以上,引发土体发生液态化流动,试验中土体起动需要的临界坡降为0.89。
Other AbstractThe distribution of moraine soil is wide and the volume of it is huge in Tibet. The disaster of moraine soil triggering debris flow often happened by glacial melting and rainfall, and caused heavy economic losses. Now the study about the mechanism of moraine soil triggering debris flow was still weak in China and abroad. By comparing the curves between pore water pressure and water content with different clay content in two consituations under artificial rainfall and Glaciermelt runoff, the characteristic and mechanism of moraine soil triggering debris flow was discussed, based on the mechanism of cohesive gravel soils triggering debris flow, laboratory experiments and theory of fractal dimension. The results were as follows.(1) Fractal dimensions of the samples are between 2. 415 and 2.674, and the soils are in one fractal dimension mainly, which means that the distribution of each gain-size group is continuous well. The tiny particles content, especially the content that the diameter was less than 0.01mm was quite relevant with fractal dimension,while the particle dimension of moraine and the particle less than 0.01mm was linear. (2)No matter the effect of rainfalling and glacial melting, the slope with moraine soil can not trigger the debris flow with lower clay content(<0.32%). The types of debris flow were happened much with the type of undercutting and collapsing. For the soil mass with less clay content(<3%), it happened oftenly. The type of debris flow of moraine is a shovelling and surface erosion. For the soil mass with higher clay content(>3%), that it the main type of debris flow triggering. (3)Under the different hydraulic condition, the influence of pore water pressure is different for moraine soil initiating debris flow.. For rainfall type of debris flow, the pore water pressure increases quickly and caused the failure of soil mass to triggering debris flow. While for glacial melting type of debris flow, the soil mass can trigger debris flow with narrow flucation of pore water pressure.(4)The mechanisms responsible for triggering a debris flow involved decreases in the static and dynamic resistance of the soil. During the process of the soil mass changing from a static to a mobile state, its cohesion decreased sharply. This would have reduced the soil strength and the kinetic energy during slipping, eventually triggering the debris flow. And the effects for the debris flow are 26%、46%、7% and 21% respectively. And that the effects for moraine soil are 16%、45%、6% and 32% respectively. (5)The types of debris flow were happened much with the type of undercutting and collapsing under the condition of simulating the glacial melting. When the hydraulic grandient increases beyond the critical value, the soil mess would mobilize. The critical hydraulid gradient for the slope is about 0.89. 
Pages104
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24608
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
朱云华. 帕隆藏布流域冰碛土体起动泥石流力学机理试验研究[D]. 北京. 中国科学院大学,2017.
Files in This Item:
File Name/Size DocType Version Access License
帕隆藏布流域冰碛土体起动泥石流力学机理试(6923KB)学位论文 开放获取CC BY-NC-SAView Application Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[朱云华]'s Articles
Baidu academic
Similar articles in Baidu academic
[朱云华]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[朱云华]'s Articles
Terms of Use
No data!
Social Bookmark/Share
File name: 帕隆藏布流域冰碛土体起动泥石流力学机理试验研究.pdf
Format: Adobe PDF
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.