本文選題：混凝土重力壩　切入點(diǎn)：FRP　出處：《大連理工大學(xué)》2014年碩士論文

【摘要】：在高烈度地震作用下,混凝土重力壩的抗震性能直接關(guān)系到下游工農(nóng)業(yè)生產(chǎn)以及人民生命財(cái)產(chǎn)的安全,具有特別重大的現(xiàn)實(shí)意義。目前我國(guó)大壩的抗震措施主要是補(bǔ)強(qiáng)加固,因此加固材料也就成為了研究的主要課題之一。近年來,新型復(fù)合材料FRP (Fiber Reinforced Polymer)在土木工程結(jié)構(gòu)加固補(bǔ)強(qiáng)中已有較廣泛的應(yīng)用,本文以Koyna混凝土重力壩為研究對(duì)象,通過數(shù)值模擬探討了FRP局部增強(qiáng)措施應(yīng)用于混凝土大壩后對(duì)于其抵抗靜動(dòng)荷載性能的改善效果。具體研究?jī)?nèi)容包括： (1)建立了FRP加固混凝土結(jié)構(gòu)的數(shù)值模型。其中混凝土采用多線性等向強(qiáng)化模型模擬,FRP布假定為線彈性材料,界面采用陸新征簡(jiǎn)化模型模擬。通過文獻(xiàn)中梁的試驗(yàn)結(jié)果對(duì)模型進(jìn)行驗(yàn)證,著重分析FRP布加固前后梁的裂縫分布及破壞形態(tài)、加固梁在不同荷載下FRP布的受力情況以及FRP布與混凝土界面的粘結(jié)滑移機(jī)理。數(shù)值計(jì)算的結(jié)果與試驗(yàn)結(jié)果吻合良好,證明了該模型的有效性,為下文FRP加固混凝土大壩的模擬提供了理論依據(jù)。 (2)FRP片材加固混凝土重力壩研究。以koyna重力壩為例,研究FRP片材對(duì)壩踵及壩頭折坡附近區(qū)域進(jìn)行加固的效果和機(jī)理。首先通過大壩在水頭超載作用下的破壞分析,對(duì)FRP的靜力加固效果進(jìn)行了研究；進(jìn)而通過混凝土重力壩實(shí)測(cè)地震激勵(lì)下的非線性響應(yīng)進(jìn)行動(dòng)力時(shí)程分析,研究了FRP材料的抗震加固效果。通過比較靜動(dòng)力荷載下壩體布置和未布置FRP片材兩種情況下的裂縫分布形態(tài)、裂縫延展過程、壩頂位移以及位移加速度、壩體主應(yīng)力分布等響應(yīng),揭示FRP片材的加固效果及作用機(jī)理。研究表明：大壩薄弱部位采用FRP片材外貼加固的措施能有效地延緩壩體的裂縫擴(kuò)展,并對(duì)分散混凝土的開裂起到了一定的作用。 (3)預(yù)應(yīng)力FRP筋加固混凝土重力壩研究。采用兩種預(yù)應(yīng)力FRP筋插筋加固的方案,并在壩踵部位將筋的兩端分別深入壩體及基巖,通過數(shù)值模擬研究了這種加固方案的效果。研究結(jié)果證明：采用預(yù)應(yīng)力FRP筋加固措施在很大程度上降低了裂縫的擴(kuò)展速度,裂縫開展情況得到很大改善,提高了大壩抵抗靜動(dòng)荷載能力。
[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.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TV642.3;TV698.23

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