【作者】 房殿荣；

【导师】 高丹盈；

【作者基本信息】 郑州大学 ， 水工结构工程， 2010， 硕士

【摘要】 黄河下游大堤是在原有民埝的基础上逐步加高而成的,普遍存在堤防质量问题,发生“冲决”、“溃决”的几率很大。因此,开展黄河下游堤防溃口土体冲刷试验研究,掌握溃口土体的冲刷特性,为防汛抢险和安全管理提供科学理论与技术支撑,具有主要的理论意义和实用价值。虽然国内外学者对溃口模型、理论模型和数值模拟做过不少研究,但是对于堤防溃口土体冲刷的试验研究尚未有统一的试验方法,更未开展系统的研究。因此,本文在分析黄河下游堤防土体基本物理力学特性的基础上,选取典型土质,开展土体冲刷模拟试验,测试各种性能参数指标,研究不同冲刷条件下冲刷量和颗分曲线随时间的变化规律以及堤防溃口破坏过程,主要研究内容如下：(1)结合本试验室试验条件,开发了一套简易且重复性强的试验设备,并利用此设备进行了32组土体冲刷试验。首次将MENSI-GS200激光三维扫描仪应用到水工模型试验中,研究了扫描方法和对扫描数据的处理方法。(2)通过不同冲刷条件下的32组模型的冲刷试验,研究了土质、干密度、流速、预制孔距堤顶距离和预制孔长度对冲刷量和颗分曲线的影响；获得了在不同冲刷条件下的冲刷量随时间变化的规律；分析了土体在不同条件下颗粒分析曲线的变化规律,研究粘粒含量和平均粒径随时间变化规律。结果表明：冲刷量的变化受流速、土质的影响较大,而密度对冲刷量变化的影响较小；流速和密度对粘粒含量和平均粒径变化的影响最为显著,土质次之,冲刷厚度对粘粒含量和平均粒径变化的影响最小。(3)通过对扫描后数据的处理,分析了口门区的变化特征、冲刷坑的变化过程和堤防溃口破坏过程；将堤防溃口破坏过程分为三个阶段,分别分析了其变化特征,探索了堤防溃口土体冲刷破坏过程中的影响因素。更多还原

【Abstract】 The Yellow River down-stream levee is formed gradually on the basis of the original China Dam, embankment quality questions are commonly existed, it is apt to happens "smash", "outburst".Therefore, it’s necessary to conduct dyke Burst soil erosion experiment and researching the lower Yellow River to master soil erosion characteristics, providing scientific theoretical and technical support for flood controling and security management, With the major theoretical and practical value. Although many researchers home and abroad have carried out the researches on Burst model, theoretical studies and numerical simulations,there haven’t formed a unified test method on soil erosion experimental studies, and not formed a systematic research. Therefore, acording to the analysis on basic physical mechanics properties of soil which was from the Lower Yellow River Dike, different representative soil was selected in order to carry out scouring experiment. Through testing various experiment parameters, the variation law with time of washing load and soil particle size distribution curve were researched, the failure process of Dyke Burst ware researched were researched.Main research subjects and results obtained from experiment are as follows:(1) Combining with the laboratory conditions, a set of simple and repetitive laboratory equipment was developed,and carried out 32 groups of soil erosion experiment by this equipment. Using MENSI-GS200 laser scanner in three-dimensional for the first time in the hydraulic model tests, the scanning method and data processing methods were studied.(2) Experiment on the 32 groups model in different erosion conditions, researched the impact of soil、dry density、velocity、the distance of Prefabricated and the length of pre-bore holes on erosion amount and the curve of grain size;obtained scouring variation with time under different conditions, analyzed clay content and average particle size variations with time.The results show that:The erosion amount changes badly which influenced by the flow velocity, kinds of soil, but the influence is smaller by density; The most significant influences are velocity and density on the change of clay content and average particle size, then is soil, scour location have a minimal impact on changes of the clay content and average particle size.(3) Changes features of entrance area, the change process of scour erosion process and the failure process of dike breach were anlyzed through scanning data processing, analyze changes features of entrance area, the change process of scour erosion process and the failure process of dike breach; So The failure process of dike burst is divided into three stages,discussed its variation and explore the affect factor of dike burst with the process of soil erosion damage in this paper.更多还原