路基上CRTSⅡ型板式无砟轨道湿度场分析

Analysis of Humidity Field of CRTSⅡ Slab Ballastless Track on Subgrade

建立路基上CRTSⅡ型板式无砟轨道湿度场计算模型,采用节点耦合法,设计1稳态+3瞬态的4阶段计算流程,按照施工顺序依次对各层构件的早期湿度场进行分析,并分析服役阶段层间积水对CA砂浆层内湿度的影响。结果表明:路基基床的稳态湿度场沿深度呈指数分布;支承层与轨道板的水化自干燥效应主要发生在浇筑后前7 d,而大气湿度的日波动性对暴露面湿度的影响深度约为10 mm;CA砂浆层的早期湿度主要受湿度扩散控制,待稳定后保持在70.0%~72.4%;CA砂浆层下界面离缝存在积水时砂浆层内湿度分布由线性逐渐向三次多项式转变,上下界面离缝均存在积水时积水区砂浆层浸泡5 d可达到100%的饱和湿度状态。

The calculation model of humidity field of CRTSⅡ slab ballastless track on subgrade was established. The node coupling method was used to design the 4-stage calculation process of 1 steady state+3 transient. The early humidity field of components in each layer was analyzed in turn according to the construction sequence,and the influence of interlayer ponding on the humidity in CA mortar layer during service was analyzed. The results show that the steady-state humidity field of subgrade bed is exponentially distributed along the depth. The hydration self drying effect of the supporting layer and track slab mainly occurs in the first 7 days after pouring,and the influence depth of the daily fluctuation of atmospheric humidity on the humidity of the exposed surface is about 10 mm. The early humidity of CA mortar layer is mainly controlled by humidity diffusion,which is maintained at 70.0%~72.4% after stabilization. When there is ponding at the lower interface of CA mortar layer,the humidity distribution in the mortar layer gradually changes from linear to cubic polynomial. When there is ponding at the upper and lower interface,the mortar layer in the ponding area can reach 100% saturated humidity after soaking for 5 days.