丹巴县江口沟泥石流发育特征及沟口危险区范围预测研究

发布时间：2018-04-03 01:30

本文选题：江口沟泥石流　切入点：发育特征　出处：《西南交通大学》2015年硕士论文

【摘要】：泥石流是一种常见的山地地质灾害,由于其暴发突然、运动迅速,常对人类生产生活构成严重威胁。泥石流堆积区是其淤积泛滥的部位,然而由于其地势相对平坦,许多山区的城镇安置在泥石流堆积区上,这为许多泥石流灾难的形成埋下了隐患。由于对泥石流危险区范围预测不足,近年来在我国西南部相继发生的多起大型泥石流灾害(如2009—2013年间在汶川、北川、绵竹等地暴发的文家沟、红椿沟、七盘沟等泥石流)不仅损毁了沟口堆积区的灾后重建成果,更对灾区人民的生命财产造成了重大损失。目前国内外对泥石流的危险区预测一般是利用基于统计学的经验公式或数学模型进行,但预测结果常常与实际差别较大,因此,探索出一种客观、可信的泥石流危险区范围预测技术显得非常必要。泥石流的数值模拟技术不仅可以反演、再现泥石流的运动发展过程,还能对泥石流灾害进行预测,为防灾减灾工作提供指导借鉴,近年来逐渐受到国内外学者的重视。论文通过现场勘查测绘,从区域地质环境条件和泥石流发育特征综合研究了江口沟泥石流的形成条件；在此基础上对泥石流的运动特征和动力特性进行了计算；最后将大型计算流体动力学软件CFX引入到泥石流危险范围预测领域,对江口沟泥石流治理前后的危险区范围进行了三维流场数值模拟。主要结论有：(1)阐述了研究区区域地质背景,从地形条件、物源条件、水源条件三个方面研究了江口沟泥石流的形成条件。根据“雨洪法”计算确定了泥石流动力学参数,调查分析了江口沟泥石流暴发历史和暴发频率。(2)建立了江口沟泥石流堆积区三维流体模型,使用大型计算流体动力学软件CFX对泥石流在堆积区的运动过程进行了三维流场数值模拟,得到了泥石流在堆积区堆积泛滥的完整过程和较准确的危险范围。(3)提出了“拦渣坝+防护堤+排导槽”的综合治理措施,并对治理后的泥石流运动过程和危险区范围进行了模拟,模拟结果证明了治理工程的可行性。基于CFX的泥石流数值模拟技术能够克服主观人为因素对危险范围预测精度的影响,得到较为准确的泥石流危险区范围,为泥石流治理工程设计提供指导借鉴。相信采用该方法对我国西南部广大受泥石流威胁的地区进行拓展研究,应能在城镇建筑选址、山区铁路选线等领域起到预防预测、避规风险的作用。
[Abstract]:Debris flow is a common geological disaster in mountainous areas. Because of its sudden and rapid movement, debris flow often poses a serious threat to human production and life.Debris flow accumulation area is the site of its siltation and flooding. However, because of its relatively flat topography, many towns in mountainous areas are located in debris flow accumulation areas, which has buried hidden dangers for the formation of many debris flow disasters.Due to insufficient prediction of the scope of debris flow risk areas, there have been many large debris flow disasters in the southwest of China in recent years (such as Wenjiagou and Hongchun gully, which broke out in Wenchuan, Beichuan, Mianzhu and other places between 2009-2013, etc.)The debris flow in Qipangou not only damaged the post-disaster reconstruction results in the gully mouth accumulation area, but also caused great loss of life and property to the people in the disaster area.At present, the prediction of debris flow risk areas at home and abroad is usually carried out by using empirical formulas or mathematical models based on statistics, but the results of prediction are often quite different from the actual ones. Therefore, an objective method is explored.It is necessary to predict the range of debris flow hazard area.The numerical simulation technology of debris flow can not only invert and reproduce the development process of debris flow, but also predict the debris flow disaster and provide guidance for disaster prevention and mitigation. In recent years, scholars at home and abroad have gradually attached importance to it.In this paper, the formation conditions of debris flow in Jiangkou gully are studied synthetically from the regional geological environment condition and debris flow development characteristics, and the motion and dynamic characteristics of debris flow are calculated on the basis of field surveying and mapping.Finally, the large-scale computational fluid dynamics software CFX is introduced to predict the hazard range of debris flow, and the three dimensional flow field of the dangerous area before and after the debris flow control in Jiangkou gully is numerically simulated.The main conclusions are as follows: (1) the regional geological background of the study area is expounded, and the formation conditions of debris flow in the estuary are studied from three aspects: topographic condition, provenance condition and water source condition.According to the calculation of "Rain Flood method", the dynamic parameters of debris flow are determined, the history and frequency of debris flow in Jiangkou gully are investigated and analyzed, and the three-dimensional fluid model of debris flow accumulation area in Jiangkou ditch is established.A large computational fluid dynamics software (CFX) was used to simulate the movement of debris flow in the accumulation area.The complete process of accumulation and flooding of debris flow in the accumulation area and the more accurate danger range are obtained.The movement process of debris flow and the range of dangerous area are simulated, and the simulation results prove the feasibility of the project.It is believed that the application of this method to the study of the vast areas threatened by debris flow in the southwest of China should be able to prevent prediction and avoid the risks in the fields of urban building location and railway line selection in mountainous areas.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.23

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