西藏东南冰湖溃决泥石流形成机制研究
文献类型：学位论文
| 作者 | 刘晶晶
|
| 学位类别 | 硕士 |
| 答辩日期 | 2008 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 程尊兰 |
| 关键词 | 西藏东南部 冰湖溃决 泥石流 形成机制 |
| 其他题名 | Debris-flow dam break and charactistics of the induced flood in the Southest of Tibet |
| 学位专业 | 岩土工程 |
| 中文摘要 | 本文是在国家自然科学基金（编号：40771024）的资助下，通过西藏近50年来发生的17次冰湖溃决事件的分析和对藏东南部然乌至培龙段典型的现场考察，试图找到冰湖溃决的机制。并对然乌至培龙段的危险冰湖进行评价。 本研究总结分析了西藏的冰湖和溃决事件的基本情况，探讨了冰湖溃决事件的时空分布特征，并选择然乌至培龙段的3个典型冰湖作为重点研究对象。对然乌至培龙段冰湖进行了卫片分析和实地考察，收集了大量第一手资料；分析了光谢错的溃决原因和过程；重点研究气候变化与冰川消长对冰湖溃决的影响；通过对土样的土力学特征分析，提出了冰湖溃决的可能破坏形式；结合堵塞坝模型试验，分析了冰湖终碛堤溃口的形成和洪水特征，并通过实例选择适当的洪峰流量公式。最后建立了冰湖溃决的危险性评价指标，并对三个典型冰湖进行了危险性评价。 本研究的主要创新在于： （1）揭示了冰湖溃决与气候异常的对应关系； （2）运用土力学原理提出冰碛湖溃决的可能公式； （3）揭示了冰湖溃决洪水引发的泥石流沿程变化规律。 通过现有资料，本文得出如下初步绪论包括： （1）溃决事件同温度关系明显，而与降水关系不大。冰湖溃决事件与气温异常有着明显的对应关系。发生溃决事件当年的前期积温增长更快，这可能导致冰川消融更快，冰川发生冰崩、冰滑坡机率增加。 （2）根据土体性质，级配良好的冰碛的可能破坏形势介于管涌和流土之间；而级配不良的冰碛容易发生管涌。光谢错冰川终碛、康窄错冰川表碛和多依错冰川表碛和侧碛都可能发生管涌破坏。 （3）溃口通常在坝体顶部形成，发生的溃决事件中，溃口多呈梯形，顶宽为坝高的3-4倍。 （4）可以用指数函数描写泥石流颗粒级配，泥石流容量越大，其颗粒分布指数越小。据此可以根据不同断面的样本推测冰湖溃决泥石流容重的沿程变化情况。 |
| 英文摘要 | This study is supported by the National Natural Science Foundation(Grant No.40771724). Based on ivestigation of glacier lakes in Tibet, this paper conducts a case study in the area along the Ranwu-Peilong Highway in the Southeast Tibet to explore the mechainism of break of the glacier lakes. First, we've summarize the characteristics and distribution of glacier lakes and lake-break events in Tibet. Then we conduct a case study for 3 typical glacier lakes along the Ranwu-Peilong Highway. We have collected a great deal of first-hand data on these lakes by field surveys and analysis of satellite images and maps. Second, we've explored the factors and processes related to break of Guangxiecuo Lake in Midui Valley.In Particular, the influences of the change of climate and ebb and flow of glacier are discussed in details. Third, we've analyzed the soil properties of different moraines and proposed several patterns of dam failures. Fourth, we've analyzed the formation of flood due to the dam failure and find the calculation of the peak discharge by combining field surveys with simulation experiments. And the debris flow resulting from the flood is also discussed. The following conclusions and novel understandings can be drawn from the study: (1) the break of glacier lake relies more on the temperature than the precipitation; a remarkable relation can be found between the temperature abnormity and the occurrence of lake break. Specifically, the break immediately follows the year with high rate of temperature accumulation; (2) The structure of soil determines the failure of moraine. The moraine with well-assembled grains is under the threat of pipng and soil flowing while the moreaine with poorly-assmbled grains is sensitive to pinping. Pinping is the most possible pattern of moraine dam failure in the study area; (3) Fairlure ofhter occurs at the to of the dam and the breach is usually of trapezoid width 3 or 4 times the height of the dam. (4) The exponential function is found fit for the grain size distribution of debris flow, with exponmet decreaing as the density increasing. Then the variation of exponment reflects the density variation of break-induced debris flow along the channel. |
| 语种 | 中文 |
| 公开日期 | 2013-05-03 |
| 分类号 | X43 |
| 源URL | [http://192.168.143.20:8080/handle/131551/5268]  |
| 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 | 刘晶晶. 西藏东南冰湖溃决泥石流形成机制研究[D]. 北京. 中国科学院研究生院. 2008. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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