板式无砟轨道CA砂浆黏弹性特征

Viscoelastic performance of CA mortar in prefabricated slab track

为研究砂浆在列车荷载作用下、不同初始弹性模量时的黏弹性变形规律,以黏弹性理论与时间硬化率分析方法为基础,拟合得到砂浆的时间硬化率特征参数,通过ABAQUS建立基于时间硬化率的CRTS I型板式无砟轨道实体模型。研究结果表明:基于时间硬化率的分析模型能很好地模拟砂浆变形行为,拟合得到的特征参数较为合理;若砂浆初始弹性模量增大,则砂浆在黏弹性变形前、后应变差值逐渐减小,位移差值逐渐增大,位移差值集中于0.2～0.6 mm,变形敏感部位约在板端2.5个扣件间距处。砂浆本身黏弹性特征引起的不可恢复变形是导致砂浆与轨道板层间离缝的重要原因之一。

To study the viscoelastic deformation laws of CA mortar with different initial Young's modulus under cyclic train loads,the viscoelastic parameters of mortar were fitted according to the equation of time hardening rate,and the model of CRTS I slab track was established through ABAQUS,based on the viscoelasticity theory and the strain analysis of time hardening rate.The results show that the viscoelastic performance of mortar can be described well with the model of time hardening rate,and the fitted viscoelastic parameters are reasonable.With the increase of the initial Young's modulus of mortar,the strain difference of mortar before and after its deforming gradually decreases,while its displacement difference increases gradually ranging from 0.2 mm to 0.6 mm.The deformation is mainly distributed on the slab end,which is about 2.5 times of the fastening spacing longitudinally.The viscoelastic performance of mortar produces an irreversible deformation,which plays a significant role in leading to the contact loss between the mortar layer and the track slab.