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泥石流重力式拦砂坝坝基扬压力实验研究
Alternative TitleExperimental study on the uplift pressure of gravity check dam
张莉
Subtype硕士
Thesis Advisor游勇
2018
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline建筑与土木工程
Keyword重力式拦砂坝 扬压力 坝基渗透 颗粒级配 泥石流性质
Abstract扬压力是一种作用在泥石流拦砂坝坝基底部的重要的竖向荷载,其取值和作用机理是拦砂坝结构设计和稳定性检算的重要内容。目前专门针对泥石流拦砂坝扬压力作用机制和计算方法的研究较少,工程设计者往往凭经验对扬压力相关参数取值,取值范围变化较大,缺乏相应的科学依据和理论参考。因此,如何科学合理的确定扬压力的关键设计参数,了解扬压力在拦砂坝基底的作用机制和变化过程,是泥石流重力式拦砂坝设计和检算亟需解决的问题,以便能更好的为泥石流防灾减灾服务。本文选取坝基土性质和泥石流性质两大影响扬压力的关键因素作为控制变量,通过自制坝基渗透和扬压力测试装置开展了一系列不同条件下的坝基渗透模型实验,系统分析了拦砂坝坝基土颗粒级配和坝前泥石流性质对坝基扬压力大小,分布及变化特征等的影响,初步得到以下结论:(1)提出了一种基于坝基土颗粒级配判断渗透稳定性的方法,即:对于含黏粗粒土,小于5mm细颗粒含量30%0.14后,表现为泥沙一体沉积,不具有颗粒分选性;当0.06
Other AbstractUplift pressure, one of the most important vertical loads acting on the check dam foundation, whose action mechanism and calculation are the crucial points for dam structural design as well as stability calculation. So far, designers usually determine the relevant parameters without scientific basis via their experience as a result of lacking reference literatures on debris dam uplift pressure home and abroad. Thus, It is urgent to study the critical technological problems that how to determine the uplift pressure’s reduction coefficient more scientific and cognize it’s action mechanism and changing process more comprehensive. Then it will get to make a better service for disaster prevention and mitigation.In order to explore uplift pressure’s action mechanism and changing process, a special experiment apparatus was designed to simulate the seepage process under the dam foundation, then a series of indoor simulation tests basing different properties of foundation soils and debris flows were conducted in this thesis. According to the analysis of experimental data, the main conclusions are listed as follows:(1) A judging criterion of seepage stability for debris dam foundation soils basing on grain composition is proposed. For the foundation soils containing clay, when 30%10%, the foundation soils are prone to be more stable; when P5≥50%, foundation deformation, foundation liquefaction and contact erosion tend to occur easily; and when P5≤30%, the dam foundation soil is susceptible to seepage deformation.(2) The properties of foundation soils and debris flows mainly affect uplift pressure’s intensity and distribution. A linear attenuation distribution characteristic of uplift pressure along the dam axis is confirmed, and the rate of attenuation are positive correlated with the uplift pressure value at the dam heel. With the prolonged deposition time of debris flow, the resultant force of the uplift pressure gradually decreases, and the resultant point gradually moves to the front of the dam.(3) A calculated formula for the uplift pressure reduction coefficient basing on the permeability coefficient of foundation soils’ has been put forward as:Ky=0.0207lnk+0.2054, and the permeability coefficient is in the range of 4.91×10-5cm/s<k<2.61×10-2cm/s.(4) Based on the fine particle concentration of debris flow slurry Cvf, a method to judge the sedimentary characteristics of debris flow with different properties is proposed as: when Cvf<0.06, the debris flow is dilute and has obvious particle sorting characteristics in the deposition process; when Cvf>0.14, the debris flow is viscous and dose not have particle sorting characteristics in the deposition process; when 0.06
Pages93
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24784
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
张莉. 泥石流重力式拦砂坝坝基扬压力实验研究[D]. 北京. 中国科学院大学,2018.
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