IMHE OpenIR  > 山地灾害与地表过程重点实验室
漂木在泥石流中输移和堵溃特征试验研究
Alternative TitleExperimental studies on characteristics of the transport and block break of driftwoods in debris flow
王道正
Subtype硕士
Thesis Advisor陈晓清
2017
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline建筑与土木工程
Keyword泥石流 漂木 输移特征 堵溃系数 流量放大效应
Abstract泥石流中携带的漂木往往具有很大的冲击破坏力,并且在沟道突缩处极易堵塞沟道形成不稳定的堆积坝,导致后续泥石流淤积,当上游淤积到一定程度后,在后续泥石流的冲击作用下,漂木堆积坝突然溃决,流量瞬间增大,形成更大规模的泥石流,使泥石流的冲击破坏能力进一步增强,造成严重的次生灾害。针对泥石流中含有大量漂木所存在的问题,本文以野外考察、理论分析、室内模型试验相结合的方式,对泥石流中漂木的分布特征和来源、漂木在沟道中的稳定性、泥石流中漂木的输移特征及其对泥石流流量的影响进行了研究,取得了一下研究成果:1. 归纳总结了漂木物源的分布特征通过野外调查,漂木主要有三种来源:①原本存在于沟道内的枯木;②植被良好的地区来自沟床或岸坡上的树木;③沟沟道两岸斜坡上树木。2. 通过试验数据,分析了泥石流中漂木输移和堵塞特征(1)漂木在泥石流表面运动过程中会发生旋转使其长轴方向趋于平行于泥石流流向,这一现象随泥石流容重的减小越明显。(2)漂木在泥石流终输移过程有三种模式:单根分散式输移、成群式输移以及介于二者之间的输移模式。(3)根据其形成机制以及堆积形态漂木堆积类型有关键漂木横向拦截型、交叉错位咬合堵塞型和盲区拦挡型三种类型,拦截率随漂木数量的增加而增加,随漂木长度的增大而增大。3. 通过试验数据,分析了漂木对泥石流峰值流量和堵溃系数的影响(1)漂木的存在改变泥石流流量的过程线,由于发生堵溃现象,流量过程线由原来相对平缓变为相对尖窄,三种泥石流容重下,粘性泥石流比稀性泥石流更容易发生堵溃现象,但堵溃规模相对较小,流量放大效应较小。(2)漂木从遇到障碍物堵塞到溃决过程经历四阶段:漂木最初堵塞阶段、漂木累积阶段、漂木临时堵塞体形成阶段、堵塞体溃决阶段;并定义堵溃系数和流量放大率来表征漂木堵溃特征,根据试验结果发现流量放大率随着漂木长度的变化先增大后降低,随着漂木量的变化也是先增大后降低,并得出了漂木泥石流堵溃系数的经验公式和流量放大率和堵溃系数之间的指数对应关系。 
Other AbstractDriftwood in the debris flow often has a great impact destructive power, and it is easy to block the channel to form a temporary unstable dam, resulting in subsequent debris flow siltation, when the upstream siltation to a certain extent, under the impact of subsequent debris flow, driftwood accumulation dam can suddenly broke, the flow of an instant increase in the formation of a larger scale debris flow, so that the impact of debris flow damage capacity to further enhance, resulting in serious secondary disasters. For the debris flow contains a large number of driftwood problems, In this paper, based on field investigation, theoretical analysis and the indoor model test, the distribution characteristics and the origin of the driftwood in the debris flow, the stability of driftwood in the channel, the transport characteristics of driftwood and the impact on discharge of debris flow are summarized and discussed, and draw the following conclusions:1. The distribution characteristics of the driftwood were summarized.Through the field investigation, for the driftwood source mainly summed up the three main sources of material: ① originally existed in the channel;② in the well- vegetation areas from the ditch bed or the potential amount of driftwood on the slope; ③ the potential amount of driftwood on the slopes of the two sides of the channel according to the survey results show that the number of channels remaining in the channel is the main source of the driftwood. 2. Through the experimental data, the characteristics of transportation and blockage of drift wood in debris flow were analyzed.(1) Through experiment phenomena found that the driftwood will rotate in the process of downstream movement of the debris flow surface to make its long axis direction parallel to the upstream debris flow and flow to the downstream with a steady angle with the fluid. This phenomenon is more obvious as the debris flow density decreases. (2) There are three modes of driftwood transport in the debris flow: a single decentralized transport, a group of transport, and between the two transport modes. (3) According to its formation mechanism and the accumulation form, there are three types: The first one is horizontal intercepting type, the second one is staggered type and the third one is dead zone type. The interception rate of driftwood increases with the increase of the number of driftwood, and increases with the increase of the length of the driftwood.3. Through the experimental data, the influence of the driftwood on the peak flow and the clogging coefficient was analyzed.(1)The existence of the driftwood has a certain impact on the flow, it can change the process flow of debris flow. The flow process line changes from the original relatively flat to relatively narrow. Three kinds of debris flow density under the analysis of test results found that viscous debris flow is more prone to clogging than dilute debris flow, but the scale is relatively small. (2)Driftwood from the encounter obstacles to the process of blocking into four stages: initial plugging stage of the driftwood, the accumulation stage of the driftwood, the stage of the formation of the temporary plugging of the driftwood, the clogging stage, and with the clogging coefficient represents the degree of blockage of the driftwood to the channel. The experimental results show that flow magnified-scale rate increases first and then decreases with the length of the driftwood increases, and increases first and then decreases with the number of driftwood increases. Under this test conditions, through the analysis of the test results, preliminary determine the variation rule of the clogging coefficient and the influencing factors of the debris flow in the channel when the driftwood exists, obtain the empirical formula of the clogging coefficient of the driftwood debris flow and the relationship between the flow magnified-scale rate and the clogging coefficient. 
Pages76
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24620
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
王道正. 漂木在泥石流中输移和堵溃特征试验研究[D]. 北京. 中国科学院大学,2017.
Files in This Item:
File Name/Size DocType Version Access License
漂木在泥石流中输移和堵溃特征试验研究.p(24550KB)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
[王道正]'s Articles
Baidu academic
Similar articles in Baidu academic
[王道正]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[王道正]'s Articles
Terms of Use
No data!
Social Bookmark/Share
File name: 漂木在泥石流中输移和堵溃特征试验研究.pdf
Format: Adobe PDF
All comments (0)
No comment.
 

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