冲击荷载下新型泥石流拦挡结构动力响应分析

发布时间：2018-06-02 01:08

本文选题：泥石流 + 拦挡结构　；参考：《兰州理工大学》2013年硕士论文

【摘要】：泥石流是发生在山区的常见地质灾害,具有突发性强、来势猛、历时短、成灾快、破坏性强、预测预报预警难度大、防御困难等特点。我国滑坡泥石流发生的区域广,损失严重,灾害遍及全国山地丘陵区,因此,对于滑坡、泥石流的预报及防治已经成为当前工程防灾减灾界十分紧迫的任务。泥石流拦挡工程是防治泥石流危害的主要工程措施。它是修建在泥石流沟上的一种横向拦挡建筑物,作为抵御泥石流的一道防线,拦挡结构对保证人们的生命财产起到了重大的作用。早期修建的泥石流拦挡坝以圬工重力式实体坝较为普遍,但是,由于重力坝其透水能力差,又是正面抵挡泥石流的冲击,所受的冲击力非常大,很容易被泥石流直接破坏。本文采用实地调研、数值模拟、室内试验相结合的研究方法,利用舟曲原地质资料以及白龙江流域泥石流的基本情况(形成过程、活动规律以及冲击机理),从结构工程专业的角度出发,提出新型泥石流防治结构体系,即钢—混凝土混合拦挡结构体系,研究其抗冲击性能,并应用于泥石流实际防治工程,用以减轻泥石流灾害,保护人民生命财产安全。本文基于计算流体动力学理论,采用流体分析软件CFX对黏性泥石流进行模拟,得到了泥石流速度场和压力场的分布特征。研究表明：流体速度在底部小于顶部,并且流速在整个流域内出现减小的趋势,由于受到拦挡坝的阻力作用,结构两侧的流速大于中间,流体翻越坝顶产生涡流,说明泥石流运动过程中具有直进性,且不发生绕流现象。本文采用流固耦合分析方法,运用有限元程序ANSYS对一新型泥石流拦挡结构在泥石流冲击力作用下的动力响应进行数值模拟,得到结构的位移时程曲线和应力时程曲线。通过对比分析新型拦挡坝与普通实体坝的响应,得到一些有益的结论。研究表明：冲击力随流速增大而增大,大块石的冲击作用是使结构破坏的重要因素,带支撑的新型拦挡结构相比普通重力坝有更强的抗冲击能力,新型结构支座反力比普通结构减小了三分之一,结构位移和应力也也比普通结构小很多。该结果为泥石流拦挡工程的设计和加固提供了参考。
[Abstract]:Debris flow is a common geological disaster occurring in mountainous area, which has the characteristics of sudden strong, strong coming, short duration, fast disaster, strong destructive, difficult to forecast and early warning, difficult to defend, and so on. The area of landslide and debris flow in China is wide, the loss is serious, and the disaster is all over the mountainous and hilly area of the country. Therefore, the prediction and prevention of landslide and debris flow has become a very urgent task in the field of engineering disaster prevention and mitigation at present. Debris flow blocking project is the main engineering measure to prevent debris flow harm. It is a kind of transverse blocking structure built on the debris flow ditch. As a defense against debris flow, the blocking structure plays an important role in ensuring people's life and property. The early construction of debris flow barrier dam is more common in masonry gravity dam, but because gravity dam has poor water permeability and is frontal to resist the impact of debris flow, the impact force is very large, it is easy to be directly destroyed by debris flow. In this paper, field investigation, numerical simulation and laboratory test are used to study the basic conditions of debris flow (formation process) in the Bailong River basin, using the original geological data of Zhouqu and the basic conditions of debris flow in the Bailong River Basin. From the point of view of structural engineering, a new type of debris flow prevention and control structure system, that is, steel-concrete mixed retaining structure system, is put forward, and its impact resistance is studied, which is applied to the actual prevention and control engineering of debris flow. In order to reduce debris flow disasters and protect the safety of people's lives and property. Based on the theory of computational fluid dynamics, the viscous debris flow is simulated by the fluid analysis software CFX, and the distribution characteristics of velocity field and pressure field of debris flow are obtained. The results show that the velocity of fluid is smaller at the bottom than the top, and the velocity of flow decreases in the whole basin. Due to the resistance of blocking dam, the velocity on both sides of the structure is larger than the middle, and the fluid surpasses the top of the dam to produce eddy current. It shows that the debris flow is straight forward and no flow around the debris flow. In this paper, the finite element program ANSYS is used to simulate the dynamic response of a new debris flow retaining structure under the impact of debris flow, and the displacement time history curve and stress history curve of the structure are obtained by using the fluid-solid coupling analysis method. Some useful conclusions are obtained by comparing and analyzing the responses of new retaining dams and ordinary solid dams. The results show that the impact force increases with the increase of velocity, and the impact of large block rock is an important factor in structural failure. The new retaining structure with support has stronger impact resistance than ordinary gravity dam. The reaction force of the new structure is 1/3 less than that of the ordinary structure, and the displacement and stress of the new structure are also much smaller than that of the ordinary structure. The results provide a reference for the design and reinforcement of debris flow retaining engineering.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU311.3

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