混凝土热-化学-损伤耦合模型与高坝碱骨料反应开裂研究

项目名称： 混凝土热-化学-损伤耦合模型与高坝碱骨料反应开裂研究

项目编号： No.51209120

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 水利科学与海洋工程学科

项目作者： 潘坚文

作者单位： 清华大学

项目金额： 25万元

中文摘要： 碱骨料反应是损害大坝混凝土耐久性的主要原因之一，其表现为骨料所含的碱活性物质与水泥砂浆中的碱溶液发生化学反应，产物吸水膨胀，导致混凝土骨料和砂浆开裂。在未来的几十年内，我国混凝土坝存在碱骨料反应的风险。另外，我国很多高坝建于高地震烈度区。因此，需建立有效的数值模型分析和预测混凝土坝因碱骨料反应引起的变形与开裂，并校核其抗震安全性。 本项目拟研究温度场、化学反应过程、应力场的耦合问题，建立分析宏观结构碱骨料反应膨胀和开裂的混凝土热-化学-损伤耦合模型；基于颗粒离散元细观模型研究碱骨料反应过程材料力学参数退化与各向异性膨胀机制，为宏观模型提供可靠的材料参数，为结构提供各向异性变形准则；在拱坝系统抗震分析模型中引入热-化学-损伤耦合模型形成拱坝长期碱骨料反应与地震响应的统一分析模型。成果可用于遭受碱骨料反应病害的混凝土坝膨胀变形和损伤破坏的分析与长期预测，评价其运行过程中各阶段的抗震稳定性。

中文关键词： 混凝土坝；碱骨料反应；细观；老化；抗震安全

英文摘要： Alkali-Aggregate Reaction (AAR) is the leading cause of dam concrete deterioration, reducing the durability of the structure. AAR is a chemical reaction between amorphous silica present in reactive aggregate and alkali in pore solution. The principal manifestation of AAR is the formation of a hydrate gel, which swells by imbibition of free water and destroys the matrix bonds and causes fracturing of aggregates and the surrounding cement paste. AAR in the realistic structures usually needs a very long period of more than 10 years to take place. This slow-evolving internal concrete damage is causing millions of dollars of damage worldwide, whereas there is no (economically) feasible method to stop the reaction, though it can be mitigated to some extent. Concrete dams may meet a risk of suffering durability problem due to AAR during their operation period in the coming decades. In addition, a number of concrete dams are located in southwest China, where is a high seismic intensity zone. Therefore, an efficient numerical modeling is required for analyzing and predicting long-term expansion deformations and damage cracking of concrete dams subjected to AAR during operation period. Seismic safety of the AAR-affected concrete dams, in which AAR expansion deformation and cracking reduce the stability of the structure, i

英文关键词： concrete dam；alkali-aggregate reaction；meso-scale；ageing；seismic safety