滚石撞击桥墩损伤模型及其参数试验研究

发布时间：2018-09-09 20:30

【摘要】：近年来地震、泥石流等地质灾害导致滚石撞击桥墩事故频繁发生并造成了严重危害,如何确定碰撞力大小对桥墩的防撞设计具有重要意义。本文基于相似理论设计了1/4缩尺的钢筋混凝土模型柱,并通过单摆试验装置对不同撞击能量以及不同撞击部位工况下进行撞击试验;同时利用LS_DYNA软件进行数值模拟。本文的主要内容如下:(1)概述了滚石撞击桥墩理论并归纳总结了当前国内外关于桥墩撞击力的主要计算方法和试验研究,提出了有待进一步研究的问题。(2)利用相似原理设计和制作了桥墩试验模型,并对其在同一截面形状的三种撞击位置、四种撞击能量等12种工况下进行了水平撞击试验。通过试验得到撞击力、墩顶位移和应力—应变响应时程曲线,分析得出了桥墩碰撞的一些规律,并拟合了撞击力计算公式。(3)利用LS_DYNA建立了滚石撞击桥墩有限元模型,对桥墩在6种不同荷载工况下进行了数值模拟。进行了试验值与模拟计算值对比,其结果吻合较好,验证了本文所采用的数值模型参数可以较准确地模拟桥墩在滚石撞击荷载作用下的动力响应。(4)分析了撞击部位和撞击高度等因素对撞击力的影响,应用Origin软件进行非线性公式拟合,提出了最大碰撞力计算经验公式。
[Abstract]:In recent years geological disasters such as earthquake debris flow and other geological disasters have caused frequent accidents of rolling stone impact on bridge piers and caused serious harm. How to determine the size of collision force is of great significance to the collision prevention design of bridge piers. Based on the similarity theory, a 1 / 4 scale reinforced concrete model column is designed in this paper. The single pendulum test device is used to carry out the impact test under different impact energy and different working conditions of the impact site, and the numerical simulation is carried out by using LS_DYNA software. The main contents of this paper are as follows: (1) the theory of rolling stone impact pier is summarized, and the main calculation methods and experimental research on the impact force of bridge pier at home and abroad are summarized. The problems to be further studied are put forward. (2) the experimental model of bridge pier is designed and made by using the principle of similarity, and the horizontal impact test is carried out under 12 working conditions, such as three kinds of impact positions with the same section shape and four kinds of impact energy. The time-history curves of impact force, pier top displacement and stress-strain response are obtained by experiments, and some laws of bridge pier collision are obtained, and the formula for calculating impact force is fitted. (3) the finite element model of rolling stone impact pier is established by using LS_DYNA. The pier is numerically simulated under six different load conditions. The experimental data are compared with the simulated results, and the results are in good agreement with each other. It is verified that the numerical model parameters used in this paper can accurately simulate the dynamic response of pier under rolling stone impact load. (4) the influence of impact position and impact height on the impact force is analyzed. The empirical formula for calculating the maximum collision force is proposed by using Origin software to fit the nonlinear formula.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U445.75

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