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泥石流梁式格栅坝拦砂与调控性能实验研究
Alternative TitleExperimental study on characteristics of trapping and regulating sediment with beam dam in debris flow hazard mitigation
孙昊
Subtype硕士
Thesis Advisor游勇
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梁式格栅坝 泥石流 水槽模型实验 拦砂与调控 自清淤
Abstract梁式格栅坝是一种常用的透过型泥石流拦砂坝,在公路、铁路等线型工程以及风景区泥石流防治中有较好的应用。目前国内外关于梁式格栅坝可参考的文献资料较少,设计者多凭借经验来确定相关参数,缺乏相应的科学依据。因此,如何科学合理的确定梁式格栅坝的设计参数,了解其拦砂与调控特性与规律,是为梁式格栅坝的推广应用而亟需解决的关键问题,使其更好地为防灾减灾服务。本文选取泥石流容重、横梁间距和沟道纵坡为主要影响因素,通过室内水槽模型实验,系统分析研究了梁式格栅坝的拦砂与调控性能,并探讨了沟内常流水和后期洪水作用下的库内自清淤特征,初步得到以下结论:(1)提出了一种考虑多因素的闭塞临界条件的综合判据。当,梁式格栅坝表现为全闭塞;当时,梁式格栅坝表现为部分闭塞;当时,梁式格栅坝表现为未闭塞;临时闭塞时的F值一般大于6.0。(2)分析得到库内淤积形态主要包括四种类型:倒勾形淤积、凹曲形淤积、溃口型淤积和直线形淤积,淤积形态类型不同,其淤积过程和机理也差异明显。(3)通过多元非线性回归分析,得到了泥石流梁式格栅坝拦沙率与相对开度和泥石流体积浓度的计算式:。(4)基于量纲分析原理,分析得到了综合考虑泥石流性质、坝体结构参数以及泥石流运动状态等因素的调节特性指标(容重衰减率和峰值流量削减率)的计算式,并根据实验结果通过最小二乘法确定了其中参数,计算结果与实验结果吻合度较好。容重衰减率:峰值流量削减率:颗粒分选效率:(5)在常流水和后期洪水冲刷侵蚀作用下,临时闭塞时的自清淤效果最为显著,其次是部分闭塞,全闭塞时的自清淤效果相对较弱,而未闭塞时坝体对清淤侵蚀基准面没有限制。但临时闭塞在洪水冲刷侵蚀下可能演化为稀性泥石流而再次致灾。清淤效果主要取决于闭塞体的侵蚀演化过程,闭塞体侵蚀打开越大,其清淤量也越大,且侵蚀清淤具有一定的随机性。(6)沟内常流水侵蚀作用下,临时闭塞时的清淤量可达原始淤积总量的6.9~20.2%,部分闭塞时则为6.4~7.8%,而全闭塞时则减少至3.3~4.6%。后期洪水侵蚀作用下,临时闭塞时第一期洪水的清淤量可达原有库内淤积总量的9.6~23.1%,而第二期洪水的清淤量仍可达20%以上,甚至可达30%;部分闭塞时第一期洪水清淤量约6.8~11.8%,而第二期洪水清淤量也有5.1~9.9%,洪水行至下游可能演化为高含沙水流;全闭塞时第一期洪水清淤量减小至6.2~6.7%,而第二期洪水清淤量则减小至2.1~5.1%。
Other AbstractBeam dam, which is one of open-type dams, has high-performance applications and potentials in preventing and controlling debris flows along highways or railways. So far, designers usually determine the relevant parameters without scientific basis via their experience as a result of lacking reference literatures on debris flow beam dam home and abroad. It is urgent to study the critical technological problem that how to determine the beam dam’s design parameters more scientific and how to assess its characteristics of trapping and regulating. Then it will get to make a better service for disaster prevention and mitigation.In order to explore the characteristics of trapping, regulating and self-empting, a series of flume model experiments on debris flow passing through beam dam is conducted in this thesis. According to the analysis of experimental data, the main conclusions are listed as follows.(1) A further criterion of blocking performance of beam dam which considers multi-factors interaction is proposed. When, beam dam shows as total-blocking; when, dam behaves as part-blocking; when, dam presents as non-blocking.(2) Four types of deposition features including inverted-hook type deposition, concave-type deposition, blocking-burst type deposition and linear-type deposition, has been discussed. And trapping mechanism makes a difference in deposition features.(3) A calculated formula for trapping sediment performance of beam dam with debris flow bulk density and spacing of transverse beams has been put forward.(4) Based on the principle of dimensional analysis a formula for determining regulative performance quantitatively considering the effects of debris flow property, structure parameter of beam dam and fluid motion state has been deduced. And coefficients of these formulas are obtained by means non-linear regression analysis. The deviation between calculated data and experimental results is allowable.a) Empirical formula for reducing rate of sediment concentration of debris flow: b) Empirical formula for reducing rate of peak discharge of debris flow: c) Empirical formula for efficiency of particle separation of debris flow: (5) Self-empting when temporary blocking is most efficient, next is part-blocking, and total-blocking by either flood or perennial run-off erosion. Meanwhile, it is not limited the base level of erosion when non-blocking. Flood may evolve to diluent debris flow after passing the beam dam and threaten the safety of downstream although it has competent self-empting. Besides, the efficiency of self-empting largely depends on evolution of blocking. The more the blocking be eroded, the more high-performance self-empting.(6) Self-empting volume under perennial run-off eroding amounts to 6.9~20.2% of total deposition volume when temporary blocking, decline to 6.4~7.8% when part-blocking and 3.3~4.6% when total-blocking. When temporary blocking self-empting volume under first flood eroding amounts to 9.6~23.1%, and more than 20% under second flood eroding; when part-blocking under first flood eroding it amount to 6.8~11.8%, and 5.1~9.9% under second flood eroding; when total-blocking under first flood eroding it amount to 6.2~6.7%, and reduce to 2.1~5.1% under second flood eroding. 
Pages80
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24619
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
孙昊. 泥石流梁式格栅坝拦砂与调控性能实验研究[D]. 北京. 中国科学院大学,2017.
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