轨道板纵向温度变形对植筋效果影响

Effect of Embedded Steel Bars Under Longitudinal Temperature Deformation on Track Slab

摘要:

温度荷载作用下的轨道板纵向伸缩变形带动锚固钢筋发生偏位，结构受力状态与设计初衷产生差异。为明确轨道板温度变形对植筋实际效果的影响，首先开展纵连板式无砟轨道温度变形监测，量化表征锚固钢筋的实际偏位量；其次建立无砟轨道植筋锚固精细化有限元模型，分析不同偏位条件下植筋胶层的损伤规律；最后明确了锚固钢筋偏位与脱胶耦合作用下无砟轨道的实际植筋效果。结果表明：轨道板纵向温度变形量可达0.946mm。锚固钢筋的偏位加剧了植筋胶层损伤，且呈现垂向自上而下的演变规律，是造成锚固体系脱胶失效的主要原因。植筋胶层与轨道板的脱黏削弱了锚固体系抵抗高温上拱变形的能力，当脱胶深度超过 200mm 后，轨道板上拱量增大了137.18%。在无砟轨道实际植筋的效果评价中需考虑轨道板的纵向温度变形，动态调整实际养护维修方案。

关键词:无砟轨道;温度荷载;纵向变形;锚固钢筋偏位;体系脱胶;植筋效果

Abstract:

The longitudinal deformation of track slab under temperature load leads to the deviation of anchor reinforcement， which could lead to differences in the structural stress state from the design intention. To clarify the actual effect of planting reinforcement， first， the temperature deformation of longitudinal slab ballastless track was monitored， which quantitatively represented the actual deviation of anchor reinforcement. Then， the refined finite element model of embedded reinforcement anchorage of ballastless track was established， which was used to analyze the damage law of embedded reinforcement layer under different deflection conditions. Finally， the actual embedded steel bars effect of ballastless track under the coupling of anchorage reinforcement deviation and debonding was clarified. The results show that the longitudinal deformation of track slab could reach 0.946 mm. The offset of the anchor reinforcement aggravates the damage of the rubber layer of the embedded reinforcement， which is the main reason for the degumming failure of the anchor system. The damage evolution of the embedded rubber layer is vertical from top to bottom. The debonding failure between the embedded reinforcement layer and the track slab weakens the ability of the anchorage system to resist high-temperature camber deformation. When the debonding depth exceeds 200 mm， the camber of the track slab increases by 137.18%. In the evaluation of the actual effect of the embedded steel bars on ballastless tracks， it is necessary to consider the longitudinal temperature deformation of the track slab and dynamically adjust the actual maintenance plans.

Key words:ballastless track;temperature load;longitudinal deformation;reinforcement deviation;system degumming;embedded steel bars effect