CRTSⅡ型板式无砟轨道板局部锈胀裂耐久性寿命预测

Durability life prediction of CRTSⅡ ballastless track slab for the local corrosion-induced cracking

以CRTSⅡ型无砟轨道板局部出现顺筋锈胀裂缝作为耐久性极限状态,在相关模型基础上提出假缝处钢筋锈蚀发展的"两阶段"实用模型,并按照"全年锈蚀深度等效"的原则确定不同区域温湿度谱下的锈蚀速度向标准温湿度谱、标准锈蚀速度进行转化的当量关系,为不同地区自然环境下轨道板结构中钢筋腐蚀速度及其耐久性寿命提供了较为实用的预测方法。以京沪铁路沿线具有代表性的北京、徐州、上海三大城市为例对各类环境下轨道板假缝处的钢筋锈蚀速度和局部锈胀裂耐久性寿命进行了预测,并建议:对通过假缝的上层纵向钢筋采取表面涂刷环氧树脂或沥青漆等措施进行防锈处理以延长无砟轨道结构的耐久性寿命。

Taking the appearance of corrosion-induced crack as the durability limit state of CRTSII ballastless track slab ,a two-stage practical model is presented on the corrosion development near the dummy joints.The equivalent relationship is built between the corrosion rate under some temperature-humidity spectrum and that under normal temperature-humidity spectrum.The practical prediction method was proposed for the corrosion rate of steel bars in the track slab in different natural environments and the service life of ballastless track slab.Take Beijing,Xuzhou,Shanghai for examples,which were representative cities along the Beijing-Shanghai high-speed railway ,corro-sion rate of steel bars in the track slab near the pre-splitting crack in different environments and the durability life for the appearance of corrosion-induced crack were predicted,and it was suggested that the upper longitudinal steel should be painted with epoxy resin or asphalt paint for the rust prevention to extend the durability lifetime of ballastless track slab.