高原水库坝基松散介质渗透—淤堵试验及机理研究

发布时间：2018-05-27 05:11

本文选题：高原水库 + 松散坝基　；参考：《吉林大学》2014年博士论文

【摘要】：西藏高原高山宽谷河流区是当地重要的农业区，由于其分布有深厚粗大的强渗透性冲洪积层，因此在这类地区兴建水库工程时，坝基渗漏问题常常存在规模大、投入高、设计施工技术复杂、防渗效果差等问题。在对以往的资料进行查阅时，发现不同地区很多水库，在没有增加任何附加防渗处理的情况下，经过几年的运行，，坝基土体出现渗透性降低、渗漏问题明显减弱等现象，且后期的水库蓄水位可以达到设计要求。对此现象，作者所在课题组做了初步的探索、研究，发现坝基渗漏减弱过程中有淤堵现象的发生，且此现象对坝基土体的渗透性有重要影响。为此结合国家自然科学基金面上项目“淤堵作用对高原水库坝基松散介质渗透性的影响及机理”（No.41072197），针对松散坝基土体的特殊性质，结合土质学、土力学、泥沙动力学、水动力学等多学科，利用自行研制的渗透-淤堵试验装置开展一系列室内渗透-淤堵模拟试验和现场渗透试验，并结合图像分析、分形分维计算及数值模拟等方法对渗透-淤堵现象进行细观分析，系统地研究高原水库坝基松散介质渗透-淤堵的整个过程。论文共分七章，第一章介绍了选题依据和研究意义，总结了工程中常见的淤堵现象、淤堵试验、研究方法、机理分析等方面的国内外研究现状及目前的研究不足，给出了论文的研究内容与技术路线，并提出了创新之处。第二章以卓玉水库上坝址线为研究对象，进行了野外实地调查取样，并开展了现场试坑双环注水试验。第三章以粗粒土为研究对象，开展渗透-淤堵试验。第四章以松散坝基土体为骨架颗粒开展了天然试样和击实试样的渗透-淤堵模拟试验。第五章以室内试验得出的结论，开展渗透-淤堵现象的细观分析与计算。第六章结合渗透-淤堵试验的宏观分析计算和细观分析计算，对渗透-淤堵机理进行分析，并利用数值模拟方法，建立了三维颗粒流渗透-淤堵数值模型，模拟了渗透-淤堵的全过程。第七章对论文进行总结，并提出今后的研究和改进建议。论文探讨了淤堵作用对坝基松散介质的减渗效应，明确了淤堵作用使土体渗透性降低的机理，提出坝基防渗设计的新理念与新思路。这将为解决高山宽谷河流坝基渗漏问题，实现人工淤堵减渗新方法奠定理论依据。限于作者理论水平和实践经验有限，难免会有错误和疏漏，不当之处敬请各位专家批评指正。
[Abstract]:The high mountain and wide valley river area of the Tibet Plateau is an important agricultural area in the region. Because of its deep and coarse strong permeable flood accumulation layer, the seepage problem of dam foundation often exists in large scale and high investment when constructing reservoir projects in this kind of area. The design and construction technology is complex and the seepage control effect is poor. When we look up the previous data, we find that many reservoirs in different regions, without adding any additional seepage control treatment, after several years of operation, the seepage of the dam foundation soil is reduced, the seepage problem is obviously weakened, etc. And the reservoir water level in the later stage can meet the design requirements. To this phenomenon, the author has made a preliminary exploration in the research group, and found that the phenomenon of silt blockage occurred in the course of dam foundation leakage weakening, and this phenomenon has an important influence on the permeability of dam foundation soil. Therefore, in connection with the project of National Natural Science Foundation of China, "the influence and Mechanism of silting on the permeability of loose medium of Dam Foundation in Plateau Reservoir" No. 41072197, in view of the special properties of soil mass of loose dam foundation, combined with soil geology, soil mechanics and sediment dynamics, In this paper, a series of indoor osmo-blockage simulation tests and field permeation tests were carried out by using the self-developed osmosis-silt test apparatus, and combined with image analysis. Fractal dimension calculation and numerical simulation are used to analyze the phenomenon of osmo-silting and the whole process of permeation and blockage in loose medium of dam foundation of plateau reservoir is systematically studied. The paper is divided into seven chapters. The first chapter introduces the basis and significance of the research, summarizes the common silting phenomenon, blockage test, research methods, mechanism analysis and other aspects of domestic and foreign research status and lack of current research. The research content and technical route of the paper are given, and the innovation is put forward. The second chapter takes Zhuoyu reservoir's upper dam line as the research object, carries on the field investigation sampling, and carries on the field test pit double loop water injection test. In the third chapter, the permeation-silt test is carried out with coarse grained soil as the research object. In chapter 4, the seepage-silt simulation tests of natural and compacted samples are carried out with loose dam foundation soil as skeleton particles. In the fifth chapter, the microscopic analysis and calculation of osmotic-silt phenomenon are carried out based on the conclusions of laboratory tests. In chapter 6, the mechanism of osmotic blockage is analyzed by combining the macroscopic analysis and meso-analysis of permeation-silting test, and a three-dimensional numerical model of permeation-silting is established by using numerical simulation method. The whole process of permeation and blockage is simulated. Chapter seven summarizes the thesis and puts forward some suggestions for future research and improvement. The paper discusses the effect of silting on the loose medium of the dam foundation, clarifies the mechanism of the silting action to reduce the soil permeability, and puts forward a new idea and new idea of the seepage control design of the dam foundation. This will lay a theoretical foundation for solving the seepage problem of the dam foundation and realizing the new method of artificial silting and seepage reduction in high mountain and wide valley rivers. Limited to the author's theoretical level and practical experience, mistakes and omissions will inevitably occur.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TV223.6

【参考文献】