泥石流动床下切侵蚀过程与机理实验研究

CORC > 成都山地灾害与环境研究所 > 中国科学院水利部成都山地灾害与环境研究所 > 成都山地所知识仓储（2009年以前）

题名	泥石流动床下切侵蚀过程与机理实验研究
作者	潘华利
学位类别	博士
答辩日期	2009
授予单位	中国科学院水利部成都山地灾害与环境研究所
授予地点	成都
导师	欧国强
关键词	泥石流沟道侵蚀侵蚀坑能量法下切侵蚀参数
其他题名	Experimental Study on the Process and Mechanics of Downcutting for Debris Flow Movable Bed
学位专业	自然地理学
中文摘要	泥石流沟道侵蚀作为一种特殊的侵蚀类型，侵蚀作用非常强烈，可掏刷暴露建筑、桥梁、堤防等工程的基础，危害非常严重。国内外在泥石流堆积方面的研究已取得较多成果，但对泥石流侵蚀的研究还甚少。因此，泥石流动床下切侵蚀过程与机理研究对于泥石流基本理论的发展以及防灾减灾工程的设计都有着重要的意义。本研究通过理论分析和室内水槽实验相结合，重点分析了泥石流动床下切侵蚀深度及临界条件和泥石流坝后侵蚀坑的形态及其极限深度和长度，并对泥石流沟道侵蚀过程中的产输砂特性进行了一定的探讨。与前人研究成果相比，取得了以下进步： 1.泥石流动床下切侵蚀深度及临界条件利用无限边坡理论对沟床泥砂体进行受力分析，推导建立了多因素表达的泥石流动床下切侵蚀深度计算公式以及沟床侵蚀临界坡度公式。泥石流动床下切侵蚀深度公式：沟床下切侵蚀临界坡度公式：开展了大量的室内水槽实验，并利用实验资料对公式进行了验证，计算值与实验值吻合良好，表明计算式合理可行。 2.泥石流坝后侵蚀坑形态及极限深度和长度 (1)泥石流坝后侵蚀坑形态根据水槽实验资料分析，泥石流坝后侵蚀坑在平面上呈椭圆形，纵剖面呈两端浅中间深的形态，并且侵蚀坑内上下游坡度不一致，下游坡度比上游坡度要缓。并根据分析，建立了侵蚀坑内上下游坡度与沟床纵坡及泥砂水下休止角之间的相关关系。 (2)坝后深度和长度的发展根据水槽实验资料分析了不同泥石流及沟床条件下，坝后侵蚀坑深度和长度随时间的发展过程。假设侵蚀坑内泥砂为“黑盒子”系统，并将侵蚀坑纵剖面形态概化为三角形，首次尝试利用能量法，根据泥石流进出侵蚀坑前后的能量之差及侵蚀坑形态变化之间的关系，建立了泥石流坝后侵蚀坑最大深度和长度计算式。并开展了大量室内水槽实验进行对公式进行了验证，计算值与实验值比较接近，表明公式合理可靠。泥石流坝后侵蚀坑极限深度计算式：泥石流坝后侵蚀坑极限长度计算式： 3.通过实验，引入下切侵蚀参数分析了泥石流动床下切侵蚀过程中的泥砂输移特性，重点分析了沟道输砂粒径组成的变化和沟道泥砂流出规模。实验结果显示，泥石流沟道侵蚀过程中的下切侵蚀参数与沟道坡度之间呈幂函数关系。同时，沟道侵蚀泥砂的流出规模与沟床纵坡、泥石流容重也呈幂函数关系，高容重粘性泥石流具有较强的输砂能力。
英文摘要	As one of the specific kinds of erosion types, the erosion effects of debris flow gully is extraordinary strong. It can erode and exposure the foundations of structures, bridges, embankments and so on with extremely sever harm. There are lots of researches on the burial of debris flow both at home and in abroad while few on the erosion of debris flow. Therefore, research on the process and mechanics of down cutting on debris flow movable bed is significant for the development of debris flow basic theories as well as the designation of prevention and mitigation engineering.By theoretical analysis and a series of flume experiments, the dissertation mainly discussed the depth and critical conditions of down cutting on debris flow movable bed as well as the shapes, maximum depth and length of scour pit below debris flow dam. In addition, this paper discussed the characteristics of sediment yield and transportation during the process of gully erosion. There are several results as follows compared with the formers:1. The depth and critical conditions of down cutting on debris flow movable bedAnalyzing the stresses of the sediment body on the gully bed by infinite side slope theory, equations with multi-factors for the depth and critical conditions of down cutting on debris flow movable bed were deduced and established.Equation for the depth of down cutting on debris flow movable bed:Equation for the depth of down cutting on debris flow movable bed:Great deals of indoor flume experiments were developed and the equations were validated by the experiment data. It indicated that the calculated values were similar to the experiment values. That is, the euations were resonable and feasible.2. The shapes, maximum depth and length of scour pit below debris flow dam(1) The shapes of scour pit below debris flow damBy analyzed the experiment results, the shape of scour pit below debris flow dam looked like elliptical shape on flat while appeared as deep in the middle and shallow at the ends on longitudinal profile. At the same time, the slope of upper and lower reaches in sour pit were not the same as the lower reach’s was slower than the upper reach’s. By regression analysis, the slope gradients in scour pit had following relationships with the longitudinal gradient of gully and the rest angle of sediment under water.the slope of upper reach: the slope of lower reach: (2) The maximum depth and length of scour pit below debris flow damThe process of the depth and length of scour pit had been analyzed by a series of flume experiment results. Presuming the sediment in the scour pit as a “black box” and generalizing the shape of longitudinal profile as triangle, equations for the maximum depth and length of scour pit were established firstly by analyzing the relationship between the energy differences of inflow and outflow and the changes of the shape of scour pit. Through the abundant flume data, the calculated values were similar to the flume values. Therefore, the theory analysis were reasonable and credible.Equation for the maximum depth of scour pit below debris flow dam:Equation for the maximum length of scour pit below debris flow dam:3. Except by using the downcutting parameter to analyze the yield and transportation during the process of debris flow gully erosion, the dissertation studied the changes of grain composition as well as the dimensions of sediments during the transportation. The results show that the relationship between the downcutting parameter and the longitudinal slope of gully is power exponent. Meanwhile, the relationship between the dimensions of sediments outflow and the longitudinal slope of gully and the density of debris flow are also power exponent. Otherwise, debris flow with heavy density and viscous has strong ability to transport sediments.
语种	中文
学科主题	灾害学
公开日期	2010-10-13
分类号	TQ1;X70
内容类型	学位论文
源URL	[http://ir.imde.ac.cn/handle/131551/2156]
专题	成都山地灾害与环境研究所_成都山地所知识仓储（2009年以前）成都山地灾害与环境研究所_山地灾害与地表过程重点实验室
推荐引用方式 GB/T 7714	潘华利. 泥石流动床下切侵蚀过程与机理实验研究[D]. 成都. 中国科学院水利部成都山地灾害与环境研究所. 2009.