带弹簧支撑的新型泥石流拦挡坝抗冲击性能研究

发布时间：2019-03-31 11:21

【摘要】：我国是世界上受泥石流灾害影响最严重的国家之一。由于泥石流具有突发性、流速快和破坏力强等特点,常常会对人类的生命和财产安全构成严重的威胁。我国泥石流的研究工作开始于20世纪60年代。到目前为止,经过50多年的研究,我国泥石流学者创建了各具特色的泥石流研究方法与防治模式,取得了显著的防灾减灾效益和生态与环境效益。但是由于泥石流从预测到防治涉及到不同的专业领域,形成了严重的学科交叉,加上其本身具有的复杂组成成分和力学机制,使泥石流的研究仍是国内外的热点与难点课题。本文在对舟曲泥石流灾害调查研究的基础上,总结了现有泥石流拦挡坝的缺点,以舟曲县三眼峪沟泥石流灾害治理工程为研究背景,提出了能够更好地抵抗泥石流大块石冲击的新型泥石流拦挡坝体系—带弹簧支撑的新型泥石流拦挡坝。同时,对这种新型弹簧支撑进行了抗冲击性能分析,结果表明,新型弹簧支撑的变形可以减小到普通支撑的1/8.84-1/10.82,支反力大约可以减小到普通支撑的1/2.8,表现出了良好的抗冲击性能,为其在新型泥石流拦挡坝中的应用奠定了基础。文中,新型泥石流拦挡坝体系的设计基于以下三个理念：(1)采用“双道防线”当泥石流规模较小时,前坝和后坝均正常工作,当特大泥石流发生时,前坝由于冲击力过大将发生塑性变形最终破坏,从而吸收一部分能量,保护了后坝的安全,后坝作为“第二道防线”可继续发挥拦挡作用。(2)利用新型弹簧支撑的缓冲作用,增加泥石流对坝体的撞击时间,从而减小泥石流冲击力的峰值,保护坝体安全。(3)泥石流大块石对拦挡坝的撞击位置通常为一个或者几个点,通过新型坝前坝及新型弹簧支撑的转换后,使一个或者几个较大的集中力变为较小的近似均布荷载传给后坝,从而保证后坝在较大泥石流冲击力作用下,也不会被撞坏,能够正常工作。由于目前对泥石流拦挡坝的数值分析多是基于泥石流浆体的冲击模拟,而实际当中,造成泥石流拦挡坝破坏的主要原因是泥石流中大块石的冲击。因此,本文利用有限元软件ANSYS／LS-DYNA强大的非线性分析功能对大块石冲击作用下新型泥石流拦挡坝和普通重力式泥石流拦挡坝的动力响应进行了详细地对比分析。分析结果表明,新型泥石流拦挡坝的响应位移、内力、应力、加速度和应变率比普通泥石流拦挡坝降低很多,动力响应最大可减小2/3左右。说明带弹簧支撑的新型泥石流拦挡坝与普通重力式泥石流拦挡坝相比具有非常好的抗冲击性能,有效解决了普通坝泥石流拦挡坝在泥石流大块石冲击作用下容易破坏的问题,为泥石流防治工作开创了新的思路。
[Abstract]:China is one of the most serious countries affected by debris flow disaster in the world. Debris flow is a serious threat to the safety of human life and property because it has the characteristics of sudden, fast velocity and strong destructive power, and it often poses a serious threat to the safety of human life and property. The study of debris flow in China began in the 1960s. Up to now, after more than 50 years of research, debris flow scholars in China have set up research methods and prevention models of debris flow with different characteristics, and have achieved remarkable benefits of disaster prevention and mitigation and ecological and environmental benefits. However, the study of debris flow is still a hot and difficult topic at home and abroad due to the fact that debris flow involves different fields from prediction to prevention and control, which leads to the formation of a serious interdisciplinary discipline, and the complicated composition and mechanical mechanism of debris flow itself, which makes the research of debris flow still a hot and difficult topic at home and abroad. Based on the investigation and research of Zhouqu debris flow disaster, this paper summarizes the shortcomings of the existing debris flow dam, based on the research background of Sanjiayugou debris flow disaster control project in Zhouqu County, A new type of debris flow retaining dam system with spring bracing is put forward, which can better resist the impact of debris flow and large rock flow. At the same time, the impact resistance of the new spring brace is analyzed. The results show that the deformation of the new spring brace can be reduced to 1? 8. 84? 1? 1? 10. 82 of the ordinary brace. The support force can be reduced to about 1 脳 2.8 of the common brace, showing good impact resistance, which lays a foundation for its application in the new type of debris flow retaining dam. In this paper, the design of a new type of debris flow retaining dam system is based on the following three concepts: (1) when the scale of debris flow is small, the front dam and the back dam work normally, and when the large debris flow occurs, the double line of defense is adopted. The front dam will eventually be destroyed by plastic deformation due to excessive impact force, thereby absorbing a part of energy and protecting the safety of the back dam. As the "second line of defense", the back dam can continue to play a blocking role. (2) the impact time of the debris flow on the dam body can be increased by using the buffering effect of the new spring support, thus reducing the peak value of the impact force of the debris flow. To protect the dam body safety. (3) the impact position of debris flow rock mass on the retaining dam is usually one or several points, after the transformation of the new dam front dam and the new spring support, One or more of the larger concentrated forces can be transferred to the rear dam by a smaller approximate uniform load, thus ensuring that the rear dam will not be damaged and can work normally under the action of a larger impact force of debris flow. At present, the numerical analysis of debris flow dam is mostly based on the impact simulation of debris flow slurry. In practice, the main cause of debris flow dam failure is the impact of large rocks in debris flow. Therefore, the dynamic responses of the new type debris flow retaining dam and the ordinary gravity debris flow blocking dam under the impact of large rock mass are analyzed in detail by using the powerful nonlinear analysis function of the finite element software ANSYS/LS-DYNA. The analysis results show that the response displacement, internal force, stress, acceleration and strain rate of the new type of debris flow retaining dam are much lower than that of the ordinary debris flow retaining dam, and the maximum dynamic response of the dam can be reduced by about 2 ~ 3. It is shown that the new type of debris flow retaining dam with spring support has a very good anti-impact performance compared with the ordinary gravity debris flow retaining dam, and effectively solves the problem that the debris flow retaining dam of common dam is easy to destroy under the action of debris flow rock mass impact. It creates a new idea for debris flow prevention and control.
【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

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