高速铁路大跨度混凝土拱桥变形监测与分析

高速铁路设计时速快,变形控制要求高。由于结构的受力特点和混凝土材料的特性,混凝土拱桥在运营过程中会出现下挠变形,直接影响轨道线形和行车安全。为保障沪昆客运专线北盘江大桥的行车安全性和舒适性,通过对其建立自动化变形观测系统,分析其变形和温度数据的变化规律,结合拟合分析方法,确定温度和变形的影响系数,研究实测数据中徐变和温度效应的提取方法。结果表明:与同期人工观测数据相比,本系统的观测精度和有效性满足要求;桥面线形受温度变化影响较敏感,在低温时,不均匀沉降差值大,桥面线形相对不平顺,随着温度升高,沉降差值减小,桥面线形逐渐趋于平顺;通过建立的拟合计算徐变分析方法得到其相对徐变变形,与规范理论值相差约6%,满足工程要求。

Deformation monitoring and analysis of long span high-speed concrete arch railway bridge

High-speed railways are designed with high speed and therefore with deformation control requirements. Due to the structural mechanical characteristics and the material properties of concrete, the concrete arch bridge inevitably exhibit downward deflection in operation, which directly affects the track alignment and operation safety. In order to ensure the driving safety and comfort of Beipanjiang Bridge in Shanghai Kunming passenger special line, an automatic deformation observation system was established to monitor the deformation and temperature changes. The extraction methods of creep and temperature effect were studied. The impact factor of temperature and deformation were determined with polynomial fitting. The results show that:The accuracy and effectiveness of the observation system satisfy the requirements; the bridge deck alignment is sensitive to the temperature change, the uneven settlement is great under low temperature, which decreases as the temperature rises; using the proposed creep analysis method, the relative creep deformation is only about 6% different from that of the theoretical value, which meets the computational precision requirements in engineering practice.