FRP材料加固混凝土重力坝数值模拟研究

发布时间：2018-04-08 22:01

本文选题：混凝土重力坝　切入点：FRP　出处：《大连理工大学》2014年硕士论文

【摘要】：在高烈度地震作用下,混凝土重力坝的抗震性能直接关系到下游工农业生产以及人民生命财产的安全,具有特别重大的现实意义。目前我国大坝的抗震措施主要是补强加固,因此加固材料也就成为了研究的主要课题之一。近年来,新型复合材料FRP (Fiber Reinforced Polymer)在土木工程结构加固补强中已有较广泛的应用,本文以Koyna混凝土重力坝为研究对象,通过数值模拟探讨了FRP局部增强措施应用于混凝土大坝后对于其抵抗静动荷载性能的改善效果。具体研究内容包括： (1)建立了FRP加固混凝土结构的数值模型。其中混凝土采用多线性等向强化模型模拟,FRP布假定为线弹性材料,界面采用陆新征简化模型模拟。通过文献中梁的试验结果对模型进行验证,着重分析FRP布加固前后梁的裂缝分布及破坏形态、加固梁在不同荷载下FRP布的受力情况以及FRP布与混凝土界面的粘结滑移机理。数值计算的结果与试验结果吻合良好,证明了该模型的有效性,为下文FRP加固混凝土大坝的模拟提供了理论依据。 (2)FRP片材加固混凝土重力坝研究。以koyna重力坝为例,研究FRP片材对坝踵及坝头折坡附近区域进行加固的效果和机理。首先通过大坝在水头超载作用下的破坏分析,对FRP的静力加固效果进行了研究；进而通过混凝土重力坝实测地震激励下的非线性响应进行动力时程分析,研究了FRP材料的抗震加固效果。通过比较静动力荷载下坝体布置和未布置FRP片材两种情况下的裂缝分布形态、裂缝延展过程、坝顶位移以及位移加速度、坝体主应力分布等响应,揭示FRP片材的加固效果及作用机理。研究表明：大坝薄弱部位采用FRP片材外贴加固的措施能有效地延缓坝体的裂缝扩展,并对分散混凝土的开裂起到了一定的作用。 (3)预应力FRP筋加固混凝土重力坝研究。采用两种预应力FRP筋插筋加固的方案,并在坝踵部位将筋的两端分别深入坝体及基岩,通过数值模拟研究了这种加固方案的效果。研究结果证明：采用预应力FRP筋加固措施在很大程度上降低了裂缝的扩展速度,裂缝开展情况得到很大改善,提高了大坝抵抗静动荷载能力。
[Abstract]:Under the action of high intensity earthquake, the seismic performance of concrete gravity dam is directly related to the production of downstream industry and agriculture and the safety of people's life and property, which is of great practical significance.At present, the main seismic measures of dams in China are reinforcement, so reinforcement materials have become one of the main research topics.In recent years, a new composite material, FRP fiber Reinforced Polymer, has been widely used in the reinforcement of civil engineering structures. In this paper, the Koyna concrete gravity dam is taken as the research object.Through numerical simulation, the improvement effect of FRP local strengthening measures on static and dynamic load resistance of concrete dams is discussed.Specific studies include:The numerical model of concrete structure strengthened by FRP is established.The concrete is simulated by multi-linear isotropic strengthening model. The FRP cloth is assumed to be linear elastic material, and the interface is simulated by the simplified model of Lu Xin.The model is verified by the experimental results of the beams in the literature. The crack distribution and failure patterns of the beams before and after the reinforcement with FRP sheets are analyzed. The stress of the FRP sheets on the strengthened beams under different loads and the bond-slip mechanism of the interface between the FRP sheets and the concrete are also analyzed.The numerical results are in good agreement with the experimental results, which proves the validity of the model and provides a theoretical basis for the simulation of concrete dams strengthened by FRP.Study on strengthening concrete Gravity Dam with FRP sheet material.Taking the koyna gravity dam as an example, the effect and mechanism of strengthening the dam heel and the area near the break slope at the head of the dam by FRP sheet are studied.Firstly, the static reinforcement effect of FRP is studied through the failure analysis of the dam under the action of water head overload, and then the dynamic time history analysis of the nonlinear response of concrete gravity dam under earthquake excitation is carried out.The seismic strengthening effect of FRP material is studied.By comparing the crack distribution pattern, crack extension process, dam top displacement and displacement acceleration, and main stress distribution of dam body under static and dynamic loads, the distribution of cracks under static and dynamic loads and those without FRP sheet are compared.The reinforcement effect and mechanism of FRP sheet are revealed.The results show that the application of FRP external reinforcement in the weak part of the dam can effectively delay the crack propagation of the dam body and play a certain role in the cracking of dispersed concrete.Research on prestressed FRP reinforcement concrete gravity dam.Two kinds of reinforcement schemes with prestressed FRP tendons are adopted, and the two ends of the tendons are penetrated into the dam body and the bedrock in the dam heel, respectively. The effect of the reinforcement scheme is studied by numerical simulation.The results show that the prestressed FRP reinforcement can greatly reduce the crack propagation speed, improve the crack development and improve the dam resistance to static and dynamic loads.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV642.3;TV698.23

【参考文献】