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网络教育学院本科生毕业论文（设计）题目：浅析大体积混凝土裂缝学习中心：广东XXX经济贸易学校奥鹏学习中心[27]层次：专科起点本科专业：土木工程年级：2012年秋季学号：12XX16303381学生：黄XX指导教师：王云洋完成日期：2015年3月15日浅析大体积混凝土裂缝1内容摘要大体积混凝土开裂后，其性能与原状混凝土性能相差很大，尤其是对耐久性（渗透性）的影响更大，严重影响结构的安全和耐久性能。因此研究大体积混凝土裂缝具有重要的工程意义。本文首先简要概述了研究的背景及国内外的研究现状，进而分析了大体积混凝土裂缝产生的三大主要原因：水泥水化热、收缩裂缝以及外界气温变化等。其次阐述了注意原材料的选择，采用合理的施工方法以及科学合理的养护措施等大体积混凝土裂缝的预防措施。再次针对已经出现大体积裂缝的处理，概述了表面修补法、填充法、结构补强法以及灌浆法等大体积混凝土裂缝的处理方法。最后本文具体分析了两个实际工程案例，分析工程的预防处理措施以及取得的效果。关键词：大体积混凝土；裂缝；处理措施浅析大体积混凝土裂缝1目录内容摘要·····························································································1引言·······························································································11大体积混凝土及其开裂机理分析··························································51.1大体积混凝土概述·····································································51.2大体积混凝土开裂机理分析·························································51.2.1温度裂缝·········································································51.2.2收缩裂缝·········································································61.2.3结构裂缝·········································································72大体积混凝土裂缝控制······································································92.1注意原材料的选择·····································································92.1.1选好原材料······································································92.1.2加强结构设计···································································92.2采用合理的施工方法··································································92.2.1降低浇筑温度和水化热·······················································92.2.2降低内外温差·································································102.2.3强化混凝土全程养护························································102.2.4改善约束条件的措施························································102.3科学、合理的养护措施·····························································112.3.1采用综合措施，控制混凝土初始温度·································112.3.2采用综合措施，提高混凝土抗裂能力·································113大体积混凝土裂缝的处理方法···························································123.1表面修补法············································································123.1.1涂覆法··········································································123.1.2增加整体面层·································································123.1.3压抹环氧胶泥·································································123.2填充法··················································································133.3结构补强法············································································133.3.1碳纤维片材加固法···························································133.3.2外包钢加固法·································································133.4灌浆法··················································································14浅析大体积混凝土裂缝23.4.1灌浆方式·······································································143.4.2灌浆方法·······································································144案例分析·······················································································164.1某水电站大坝裂缝预防分析·······················································164.1.1工程概况·······································································164.1.2预防措施·······································································164.1.3取得的效果····································································174.2案例二——某写字楼裂缝处理分析··············································184.2.1工程概况·······································································184.1.2处理方法·······································································194.1.3取得效果·······································································206结论·····························································································16参考文献···························································································17浅析大体积混凝土裂缝1引言近年来，随着我国改革开放的不断深入，经济快速的发展，使得我国的建筑行业也得到了迅速的发展，因此建筑技术以及建筑规模均得到不同程度的扩大，诸多城市出现了大型现代化技术设施，而且这一趋势还在继续增加，而众所周知混凝土结构具有价格便宜质量好等特性的材料，施工操作较为方便，可装饰性极强，此外其承载力也非常大，也受到人们越来越多的喜爱，所以大体积混凝土已成为大型设施或结构的重要组成部分[1]。因此，探讨裂缝产生的原因和预防措施对防止大体积混凝土裂缝的出现有着重要的意义。对于大体积混凝土裂缝控制的系统研究，是从20世纪30年代中期美国修建鲍尔德坝(现改称胡佛坝)开始的。30年代初期，美国所修建的几座混凝土坝产生了裂缝，所以美国商务局在修建胡佛坝时(胡佛坝是当时世界上最高大的混凝土建筑物)，进行了系统的温度场及温度应力的研究，提出了柱状分块，薄层浇筑，并采用水管冷却，低热水泥等降温措施，从而防止了危害性裂缝的形成[2]。这种研究成果至今仍有普遍影响。随着科技进步，管理水平的提高，40年代美国陆军工程师团又发展了预冷骨料，通仓浇筑方法，规定混凝土出机温度应控制在10℃以下，60年代又采取了泡沫塑料坝面保温等措施来防止表面裂缝[3]。以上这一系列措施基本上都是从控制混凝土浇筑块温度变化幅度着眼的，一直沿用至今，行之有效。从实际设计和施工水平方面看，自40年代至今，各国(如美国、俄罗斯、巴西和中国等)对大体积棍凝土的裂缝问题的研究都做了深入的探讨，并提出了一些防裂措施[4]。就国内而言，袁勇（2004）分析了现浇混凝土早期性能特点和早期应力、应变发展规律介绍了结构特性、环境因素对混凝土性质变化作用机理。提出了混凝土结构的时变应力分析理论。对早期裂缝控制的基本理论与实际应用方法进行了阐述。刘海成（2005）在大体积混凝土应力场计算中，混凝土的弹性模量和徐变变形都与温度有关，温度场应力场存在耦合现象。根据温度损伤和温度对徐变的影响,建立了考虑温度影响的混凝土弹性模量表达式和徐变应变计算的递推公式。应用粘弹性与损伤耦合和正交各向异性损伤理论,描述了混凝土在高应力水平下的非线性徐变特性和由于微裂缝扩展引起的刚度退化与应变软化,建立了考虑温度影响的大体积混凝土结构应力场分析的有限元表达式。程志（2010）:超大体积混凝土在水泥水化时,会形成外低内高的温差,这种温差会使超大体积混凝土内部温度分布不均匀,会引起质点发生的变形不一致,从而产生内约束。超大体积混凝土中心由于温度较高,所产生的热膨胀也较表面大,因而在混凝