IMHE OpenIR  > 山地灾害与地表过程重点实验室
Alternative TitleThe control effect of Multi-herringbone water-separation system to debris flow and its design method based on experimental research
Thesis Advisor韦方强
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline岩土工程
Keyword泥石流 多级鱼脊型水石分离系统 粗颗粒调控效应 结构设计 实验研究
Abstract泥石流拦砂坝(包括实体坝、开口坝和格栅坝等)是常用的泥石流防治工程类型之一,但在应用中常因堵塞和淤积而导致拦砂坝的拦挡功能削弱甚至丧失。为了解决这一问题,鱼脊型水石分离结构被设计出来用于防止泥沙石块堵塞导致的淤积。实验研究表明鱼脊型水石分离结构能克服已有透水型拦砂坝易堵塞而难持续发挥拦砂功能的问题。但是,由于受地形等条件的限制,储存分离出的粗颗粒的停淤场容量有限,单个水石分离结构难以发挥其作用,需要进行多级结构的配置,综合调控泥石流的物质和能量流动,逐级降低其破坏能力,从而达到减灾目的。基于已有的研究基础和实际需求,对鱼脊型水石分离结构开展了进一步的研究,定义了多级鱼脊型水石分离系统的概念,对其功能特征进行分析,提出了表征其功能特征的一套指标体系,通过实验验证了多级鱼脊型水石分离系统对泥石流物质和能量的调控效果,得出了主要功能指标参数与结构配置参数之间的定量经验关系,探讨了多级鱼脊型水石分离系统主要系统参数的确定方法,结合已有的研究成果,综合提出了完整的多级鱼脊型水石分离系统设计方法。主要研究成果如下:(1)多级鱼脊型水石分离系统是由多个鱼脊型水石分离结构有机配置而成的系统工程,属于透水型拦砂坝泥石流防治系统工程。通过逐级选择性地分离拦截不同粒径的粗颗粒,调控泥石流的物质和能量流动(如减小排泄物颗粒粒径、减少泥沙排泄量、降低泥石流浓度、降低泥石流冲击力等),降低泥石流的破坏力,达到减灾目的。(2)采用了颗粒平均粒径、分选系数、粒径段分离比、粗颗粒分离率、固体物质总分离率、有效分离率、泥沙储存率、容重变化率等12个指标来描述多级鱼脊型水石分离系统的功能特征。这些指标分别从固体物质颗粒分布特征、固体物质量、泥石流性质和泥石流能量的变化特征等方面来描述多级鱼脊水石分离系统对泥石流的粗颗粒调控效应。(3)从能量调控的角度,以最小设计分离粒径作为控制泥石流冲击力的调控目标,通过结构塑性分析法分析建构筑物抗冲击破坏条件,由此反算出所需调控的最小颗粒粒径;从物质调控的角度提出了以分离物分选性和调控后流体容重作为调控目标,并推导出了调控后的流体容重的理论计算公式,通过实验数据验证了该公式准确性和可行性。(4)通过模拟实验,证实了多级鱼脊型水石分离系统具有逐级持续性分离粗颗粒的功能。从上游至下游分离物的平均粒径逐渐变小,分选性逐渐变好;排泄物料的平均粒径变小,可输移性变好;通过逐级调控,流体容重逐渐减小,携带的能量值也逐渐减小。通过对实验数据的统计回归分析结合类推法、理论分析等方法,得出了物质分离率、粗颗粒分离率、有效分离率及调控后流体容重与级数、设计分离粒径组合、输入固体物质颗粒级配之间的定量经验关系,并分析了系统级数和设计分离粒径组合对系统调控效应的影响。(5)提出了多级鱼脊型水石分离系统主要参数的确定方法,采用传统试算法进行参数的初步配置,结合多目标模糊决策模型,对符合条件的初步配置方案进行比选优化,确定相对最优配置方案。在此基础上,提出了多级鱼脊型水石分离系统设计流程,并以实例加以运用。本研究的创新性主要体现在如下两个方面:(1)提出了采用鱼脊型水石分离结构的多级配置来实现泥石流减灾,并从物质调控和能量调控两方面来分析多级鱼脊型水石分离系统的调控效应,建立针对性的调控效应表征指标,通过实验研究确定主要调控效应指标与结构配置参数之间的定量关系; (2)提出了鱼脊型水石分离结构的多级配置方法。采用试算法+多目标模糊决策法来确定多级鱼脊型水石分离系统关键参数的相对最优配置方案,并在此基础上提出了多级鱼脊型水石分离系统的设计方法。
Other AbstractDebris dams (including solid dam and open type dam) are prevalent structure countermeasures for debris flow prevention and mitigation, but the function of sediment control by open type dams are often weakened or even lost by clogging and deopsition of the openings in application. In order to solve this problem, herringbone water-sediment separation strcuture (HWSS for short hereinafter) was invented and proved to be effecient in overcome the issues mentioned above. However, it is limit in sediment control and storage for single HWSS due to the constraint of topographic condition and structure demensions. Therefore, mutiple HWSS system (MHWSSS for short) is needed to gradually and continuously separate coarse sediment carried by debris flow, control its movement and dissipate energe to decrease the damage capability. Based on previous study and practical neccessity, this dissertation promoted further study on MHWSSS. Firstly, take out therotical study on MHWSSS including giving an explicit definition of MHWSSS, analyzing its function charateristics, establishing a series of evaluation idicactors and proposed therotical method to decide the targets for sediment control. Then carry out a set of model tests to verify the control effect of MHWSSS, analyze the relationship between functional indicators with system structural parameters and particle size distribution. Depending on therotical analysis and experiment results, propose the decision method for key seystem parameters and put forward the whole design proccedure for MHWSSS's design. Main achievments of this study are summed up as follows: (1) MHSSS is a systematic engineering that consists of several HWSSs, which belongs to open type dam system. By separating coarse debris structure by structure, it can control sediment discharge and dissipet energe carried by debris flow gradually and continously, such as decrease the mean diameter of discharged particles, reduce the amount of sediment discharge, lower the sediment concentration of debris flow and bring down debris fow impaction) and thus decrease the destructive power of debris flow for better debris flow mitigation. (2) Based on the characteristic of the control function of MHWSSS, a set of parameters, including medium diameter, sorting coeficient, separation ratio, coarse separation rate, total separation rate, effective separation rate, sediment storage rate, changing rate of fluid density and so on, are used to desccribe the control effect of MHWSSS in four aspects: characteristic of solid particle size distribution, volume of solid material, fluid physical property and energe feature.(3) From the energe regulation aspect, the minume design diameter can be backcalculated from the analysis of arctechture failure condition to debris flow impact; sorting coefficient of the separated particles and fluid density after regulated by MHWSSS are chosen to be other objective parameters from the perspective of sediment control. Calculation formula for regulated fluid density was derived and verified by experimental data.(4)According to model tests, sorting property of separated material increases from upstream to downstream while average diameters for both separated material and the disharged decrease. Fluid density and energe value are both reduced. All these indicate that MHSSS can play the control effect gradually and continuously. Regressive analysis and analogical method reveal quantitative empirical relationships among main parameters and structure numbers, combination of design separation diameters and grain size distribution. Structure numbers influence the whole system stability while combinations of design separation diameters influence the synergitical work among structures.(5) Put foward the design method for main system parameters and the whole procedure for the MHWSSS design. By Analyzing basic principle for design of main system parameters, traditional iterative calculation method was adopted for preliminary decision of system parameters. Multi-objective fuzzy decision model was used for scheme comparision and optimization. Based on this, intergral design method for MHSSS was proposed and practise it with an example.The innovations of this research can be concluded in two aspects:(1) We proposed the idea of using MHWSSS instead of HWSS for better debris flow migtigation, analyzed its control effect from the perspective of material control and energe dissipation, established a set of parameters to depict the control effect and got quantive emprical relationships between system parameters with those paramters according to model tests.(2)Two-step method was used to decide main system parameters, that is, iterative calculation method for preliminary decision and multi-objective fuzzy decision model for scheme comparation and optimization. On this basis, complete design method was proposed for MHSSS. 
Document Type学位论文
Recommended Citation
GB/T 7714
谢湘平. 基于粗颗粒调控效应的多级鱼脊型水石分离系统设计方法实验研究[D]. 北京. 中国科学院大学,2017.
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