钢构泥石流格栅坝抗冲击性能研究

发布时间：2018-12-25 13:40

【摘要】：近年来泥石流灾害频发,其暴发突然、破坏大,给人民的生命和财产安全带来巨大隐患。我国饱受泥石流灾害的侵扰,尤其是甘肃舟曲8.8特大泥石流灾害震惊了世界,对该地区造成了毁灭性的破坏。自上世纪60年代始,我国已展开了关于泥石流的研究工作,在泥石流监测预警、形成过程、灾害治理技术等多方面取得了显著的成绩。但由于泥石流复杂的组分以及力学机制,使对于泥石流防治结构的研究较为困难。本文以舟曲三眼峪泥石流灾害治理为背景,指出导致防治结构损毁最主要的原因是泥石流中巨石冲击破坏,对泥石流巨石冲击作用进行研究。总结泥石流防治体系的防治特点,利用非线性有限元软件ANSYS/LS-DYNA对现有钢构格栅坝在泥石流巨石冲击作用下的抗冲击性能加以研究。此外,在现有钢构格栅坝防治性能的基础上提出了带支撑钢构格栅坝这一改进防治结构,同样利用LS-DYNA软件对带支撑钢构格栅坝的抗泥石流冲击性能进行分析,并与现有钢构格栅坝的分析结果做出对比。对现有钢构格栅坝的研究结果表明：(1)作用在钢构格栅坝上的冲击力大小与被冲击构件刚度密切相关,被冲击构件刚度越大,结构受到的冲击力越大；(2)现有钢构格栅坝在冲击作用下,冲击作用部位、结构支座部位及梁柱节点部位响应较大,设计时应予以加强；(3)钢构格栅坝不同位置遭受冲击作用时结构响应完全不同,与冲击力作用在梁柱节点时相比较,冲击力作用在构件中部时结构整体响应明显较小。对带支撑钢构格栅坝的研究结果表明：(1)带支撑钢构格栅坝可以有效的减小泥石流巨石冲击下结构的位移,就本文的带支撑钢构格栅坝而言,其在现有钢构格栅坝基础上位移减小了50%之多；(2)带支撑钢构格栅坝的柱底支反力会有所增大,个别柱脚支反力较原反力增加了1倍,工程设计时该类边柱柱脚应适当予以加强；(3)选取支撑布置形式合理的带支撑钢构格栅坝能有效减小结构各单元应力,可使支撑作为耗能构件消耗冲击作用能量,进而保护主体结构免受冲击破坏。以上研究结果为泥石流拦挡工程中钢构格栅坝的设计提供了参考,为其应用于工程实践奠定了基础。
[Abstract]:In recent years, debris flow disasters occur frequently, which suddenly break out, and bring great hidden danger to people's life and property safety. China suffered from debris flow disasters, especially in Zhouqu, Gansu Province, which shocked the world and caused devastating damage to the region. Since the sixties of last century, China has carried out research work on debris flow, and has made remarkable achievements in monitoring and warning of debris flow, formation process, disaster management technology and so on. However, it is difficult to study the structure of debris flow prevention because of its complex composition and mechanical mechanism. Based on the disaster control of debris flow in Sanyanyu, Zhouqu, this paper points out that the main reason of preventing and controlling structural damage is the impact damage of rock boulder in debris flow, and studies the impact of rock boulder on debris flow. The characteristics of debris flow prevention and control system are summarized and the impact resistance of existing steel grille dams under the impact of debris flow boulders is studied by using nonlinear finite element software ANSYS/LS-DYNA. In addition, based on the existing prevention and control performance of steel grid dam, the improved structure of steel grid dam with support is put forward, and the impact resistance of steel grid dam with support is also analyzed by using LS-DYNA software. The results are compared with the analysis results of the existing steel grid dams. The research results of the existing steel grid dams show that: (1) the impact force acting on the steel grid dam is closely related to the impact member stiffness, the larger the impact member stiffness is, the greater the impact force is; (2) under the impact action of the existing steel grille dam, the impact position, the structural support part and the Liang Zhu joint part should be strengthened in the design; (3) the structural response of steel grille dam is completely different when it is subjected to impact at different positions. Compared with the impact force acting on Liang Zhu node, the overall response of the structure is obviously smaller when the impact force is applied in the middle of the member. The results show that: (1) steel grid dam with support can effectively reduce the displacement of structure under debris flow boulder impact, as far as the steel grid dam with support is concerned in this paper, The displacement is reduced by as much as 50% on the existing steel grid dam foundation. (2) the reaction force of the column bottom of the steel grid dam with support will increase, and the reaction force of individual column foot will increase by 1 times compared with the original reaction force, so the side column foot should be strengthened properly in the engineering design; (3) the stress of every element of the structure can be effectively reduced by selecting the steel grid dam with reasonable bracing arrangement, which can make the bracing consume the energy of the energy dissipation, and then protect the main structure from the impact damage. The above results provide a reference for the design of steel grille dam in debris flow blocking project and lay a foundation for its application in engineering practice.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV312;TV649;P642.23

【参考文献】