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小江流域典型泥石流堆积扇演变和风险评估
Alternative TitleEvolution and Risk Assessment of Typical Debris Flow Fans in Xiaojiang River
Language中文
李彦稷
Thesis Advisor胡凯衡
2016
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Name硕士
Degree Discipline建筑与土木工程
Keyword泥石流 扇形地 危险性评价 承灾体风险分析 遥感
Other Abstract

泥石流扇形地是泥石流流域的重要组成部分,也是山区人类生产生活的重要场所。泥石流扇形地风险性评估研究对泥石流扇形地土地资源开发、利用具有重要意义。本文选择小江流域泥石流暴发频繁的两条泥石流沟:蒋家沟和大白泥沟的扇形地为研究对象,利用1987~2014年陆地卫星影像数据,分析蒋家沟、大白泥沟泥石流堆积扇危害范围在近28年间的变化特征;通过野外调查、采样和小型水槽实验,结合解译的泥石流扇形地危害变化范围,分析气候、泥石流及其输沙特征对泥石流的扇形地危害范围的影响,并基于泥石流扇形地形态特征和泥石流扇形地危害频率建立了泥石流扇形地危险性评估模型;在前人提出的泥石流扇形地承灾体易损性分区基础上,结合泥石流危险性评估模型,计算了大白泥沟泥石流扇形地的风险变化。主要研究工作和结论如下:(1)解译了1988~2014年蒋家沟和大白泥沟流域的陆地卫星遥感影像数据,并结合野外调查对遥感解译结果进行修正,发现从1987到2014年蒋家沟和大白泥沟泥石流扇形地危害面积呈现退缩趋势。这与小江流域近28年来的气候变化特别是降水的减少呈现明显的正相关关系。同时,泥石流体本身的容重、颗粒组成及输沙特征不同也对泥石流扇形地危害范围有显著影响。粘性泥石流浆体较稀性泥石流浆体在堆积区形成的淹没范围小,但淹没深度深;含有较多大颗粒物质的泥石流,形成的泥石流扇形地危害范围小,但危害深度大。反之,则形成的危害范围大,危害深度小。(2)泥石流扇形地上距离泥石流出山口越远,与主流线夹角越大的位置,受泥石流危害越小。根据这一特点,在野外实地调查和模型实验的基础上,建立了以距扇顶距离、与扇主轴夹角和危害频率为变量的定量扇形地危险性分布模型。以大白泥沟为实例,通过DEM地形和多时段遥感数据获得大白泥沟扇形地网格单元的距扇顶距离、与扇主轴夹角和危害频率,计算了大白泥沟扇形地的危险性分布,并用植被指数的分布验证了该模型的合理性。(3)基于前人提出的泥石流扇形地承灾体易损性分区模型,将大白泥泥石流扇形地易损性分为重度易损区、重度易损区、轻度易损区和微小度易损区,并分别赋权重。采用遥感影像分析方法,将大白泥泥石流扇形地承灾体分为耕地、林地、建筑用地和交通用地四类,并通过野外调查,获得不同承灾体实际价值。综合本研究中提出的泥石流扇形地危险性定量计算模型和耕地、林地、建筑用地、交通用地四类承灾体的实际易损性,计算了大白泥泥石流扇形地不同时期堆积扇风险性分布,编制扇形地风险变化图。 

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Debris flow was one of the common geologic hazards in mountainous areas. As the essential component of debris flow, the debris-flow fans were the fundamental land resource for producing and living activities of human beings. Evaluating the dangerousness and risk of debris-flow fans, could not only direct the plan of land resource utility development in the fan area, but also provide a reference for the prediction and evaluation of the risk in debris flow ditches. This research set Jiangjia Ravine and Dabaini Ravine in Xiaojiang watershed, where the debris flow occured frequently as the study area, analyzed the characteristics and impact factors of debris-flow fan variation, and put forward a risk evaluation model of typical debris-flow fan areas, by means of field investigation, minitype flume experiment and Landsat data(1987~2014) analysis. The results stated as follows:(1) This research revealed that the range of dangerous area in Jiangjia Ravine and Dabaini Ravine debris flow fan was shrinking during the year 1987 to 2014, based on the remote sensing interpretation and field investigation, which showed a significant positive relationship with the precipitation. Meanwhile, the characteristics of debris flow could influence the dangerous range of debris flow fan: the slurry of debris flow with less great grain materials forms small debris-flow fan, but the thickness is huge; whiles, slurry with small unit weight forms large debris-flow fan, associated with large dangerous area.(2) In the debris flow fan area, the farther from mountain-pass and the larger angle with flow direction was, the less threaten from debris flow would be. According to these characteristics, this research constructed a quantitative distribution model of fan dangerousness with variables of distance to the fan-top, angle with flow direction and endangered frequency, based on field investigation and model validation. Take the Dabaini Ravine as an example, this research calculated the dangerousness distribution of the debris flow fan in Dabaini Ravine and validated the rationality of the model by the analysis of investigation indexes distribution, with the distance to the fan-top, angle with flow direction and endangered frequency of ground grid cell in ofdebris flow fan, Dabaini Ravine acquired from DEM and multi period RS data.(3) Based on the vulnerability and regionalization model of hazard-bearing body put forward by former researchers, this research divided the Dabaini Ravine into severe vulnerability, moderate vulnerability, mild vulnerability and minor vulnerability. Through analysis of remote sensing images, this research divided the hazard-bearing body into farmland, forest, building land and transportation and acquired the actual values of different hazard-bearing bodies by field investigation. Comprehensive analyzed the dangerousness model of debris flow fan and vulnerability of hazard-bearing bodies, this research calculated and plotted the risk distribution of depositional fans in different phrases. 

Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/18985
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
Recommended Citation
GB/T 7714
李彦稷. 小江流域典型泥石流堆积扇演变和风险评估[D]. 北京. 中国科学院大学,2016.
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