高寒、高海拔地区钢与混凝土界面的温致粘结损伤时变演化机理及对高速铁路桥梁行车安全的影响

Because the temperature and humidity in the plateau and cold region are more complex and changeable, the interface of steel-concrete composite bridge in serving state is easily damaged by the temperature effect. Meanwhile, the interface temperature-induced damage would develop and become worse by shrinkage and creep effect. This is not only a serve threaten for structural performance, but also a new challenge to the safety and reliability of high-speed train operation. Considering the relationship between the structural service performance and train running safety, the time-dependent of interface temperature-induced damage and its impact on the safety of high-speed railway bridge are investigated. Based on the study on long-term evolution mechanism of the interfacial temperature-induced damage, the mechanical properties of steel-concrete composite structural bridge are studied. Considering the coupling effects between contact nonlinear caused by temperature-induced damage interface and creep, the long-term static behavior is studied. The long-term dynamic performance of steel-concrete composite bridge is also investigated. Through the study of safety and comfortable evaluation of high-speed train running, the key controlling index of interface temperature damage in plateau and cold region is retrieved. The micro -local-overall method is introduced to this project, and it is expected to reveal the mechanism of the thermal damage of steel and concrete interface at plateau and cold region. It is of great significance to put forward the controlling index, optimize the structural performance and ensure the safety and reliability of the high-speed train running.

高寒、高海拔地区的温度与湿度呈现出复杂多变且变化剧烈的新特点，服役的钢-混凝土组合结构桥梁界面易因温度效应而发生损伤。同时，收缩徐变导致界面温致损伤的时变演化不仅对结构性能提出了严峻的考验，也给高速列车安全可靠运行带来了全新挑战。项目从结构服役性能到列车安全运营映射的角度，提出界面温致损伤时变演化机理及其对高速铁路桥梁行车安全的影响研究。通过研究界面温致损伤的长期演化机理，考察其对结构宏观力学规律的影响；研究界面温致损伤的接触非线性与时变耦合效应下的长期结构行为；研究钢-混凝土结构桥梁长期动力性能；研究界面温致损伤条件下钢-混凝土组合结构桥梁列车运行的安全舒适性评价，反演高寒、高海拔地区界面温致损伤控制的关键指标。项目采用微观到局部、局部到整体的研究方法，有望全面揭示高寒、高海拔地区钢与混凝土界面温致损伤的产生和发展机理，对提出控制指标、优化受力性能和保障列车运行的安全可靠具有重要意义。

项目从结构服役性能到列车安全运营映射的角度，提出界面温致损伤时变演化机理及其对高速铁路桥梁行车安全的影响研究。研究内容包括：结合剪力钉的实际焊接过程和温度场影响，研究焊接温致残余能量对剪力键的损伤机理；通过分析常温环境与高寒、高海拔地区大温差环境条件下界面剪力键的损伤规律，建立不同温度对剪力键的粘结性能和工作性能的影响模型；以更适合高寒、高海拔地区应用的地聚物混凝土为对比，针对山区典型的钢-混凝土组合梁和钢管混凝土拱桥，获得考虑界面损伤的约束收缩开裂和界面滑移效应时变规律；结合实际桥梁工程，引入变温、变湿环境条件下时变分析理论，探明钢桁加劲连续刚构桥、组合梁桥、钢管混凝土拱桥和波形钢腹板组合结构桥梁长期性能演化规律；最后，利用车-桥耦合分析模型，建立温度变化对铁路桥梁自振频率和刚度变化的概率模型，结合行车舒适度要求，分析界面损伤对铁路桥梁运行安全的影响。