高速铁路CRTSⅢ型预制轨道板平面度关键影响参数

针对个别线路CRTSⅢ型轨道板脱模时已存在上拱的问题,建立了轨道板-模板一体化分析模型,研究预应力施加、混凝土收缩等因素对预制轨道板平面度的影响规律。结果表明:预应力及其偏心、轨道板顶面和底面弹性模量差异、养护过程中温度梯度对预制轨道板平面度影响较小,底模承轨槽约束条件下的混凝土收缩是影响预制轨道板平面度的关键因素。轨道板预制过程中混凝土收缩控制试验表明,在保证模板精度条件下,养护过程中补水可显著减小预制轨道板平面度上拱幅值。

Key Influential Parameters on Flatness of CRTS Ⅲ Prefabricated Track Slab for High Speed Railway

In view of the problem of camber existing in the demoulding of CRTS Ⅲ track slab,an integrated analysis model of "track slab-mold" was established to study the influence rules of prestress application,concrete shrinkage and other factors on the flatness of prefabriacted track slab.The results show that prestress and its eccentricity,the difference of elastic modulus between the top and the bottom of track slab,and the temperature gradient on track slab in the maintenance process have little influence on the flatness of prefabriacted track slab,and the concrete shrinkage under the constraint condition of the mold bottom rail-bearing groove is the key factor to affect the flatness of prefabriacted track slab.The test of concrete shrinkage control in the prefabrication process of track slab shows that under the condition of ensuring the accuracy of mold,the amplitude of camber on the flatness of prefabriacted track slab can be significantly reduced by adding water during maintenance.