Viscoelastic deformation behavior of cement and emulsified asphalt mortar in China railway track system I prefabricated slab track  

中国铁路轨道系统Ⅰ型板式无砟轨道中水泥乳化沥青砂浆的粘弹性变形分析研究

作　　者：Juan-juan REN Hao-lan LI Xiao-pei CAI Shi-jie DENG Ji WANG Wei DU 

机构地区：[1]MOE Key Laboratory of High-speed Railway Engineering,Southwest Jiaotong University,Chengdu 610031,China [2]School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China [3]School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China

出　　处：《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》2020年第4期304-316,共13页浙江大学学报（英文版）A辑（应用物理与工程）

基　　金：Project supported by the National Natural Science Foundation of China(No.51578472)。

摘　　要：Under repeated train-induced loads, cement and emulsified asphalt mortar(CA mortar) as a viscoelastic material has a time-dependent deformation, part of which is irreversible. This could lead to debonding between the mortar layer and the track slab. Based on the theory of viscoelasticity and the analytical method of the time hardening law(THL), the viscoelastic deformation behavior of CA mortar was studied. Using ABAQUS, we established a solid model of China railway track system(CRTS) Ⅰ prefabricated slab track, with CA mortar at different initial Young’s moduli under cyclic loading corresponding to the influence of actual train loads. The results reveal that the fitted parameters of the THL for CA mortar are suitable for describing its viscoelastic deformation. As the initial Young’s modulus increases, the strain difference before and after cyclic loading gradually decreases, and the displacement difference increases from 0.2 mm to 0.6 mm. The deformation mainly occurs at the end of a mortar layer with longitudinal distribution of about 2.5 times the fasteners’ spacing. It follows that the viscoelastic performance of CA mortar is one of the most important reasons that cause debonding underneath the track slab. Therefore, we suggest that the adverse effects of viscoelastic behavior of CA mortar should be considered when researching such deformation and damage.目的:作为粘弹性材料,水泥乳化沥青(CA)砂浆的变形依赖于时间,且包含不可恢复变形,使得轨道板与CA砂浆层之间形成离缝,进而影响轨道的结构受力与变形。本文旨在研究CA砂浆在列车荷载作用下、不同初始弹性模量时的粘弹性变形规律,以期为轨道结构的维修养护提供参考。创新点:1.以粘弹性理论与时间硬化率分析方法为基础,拟合得到CA砂浆的时间硬化率特征参数;2.建立基于时间硬化率的中国铁路轨道系统(CRTS)I型板式无砟轨道实体模型,成功模拟了CA砂浆的粘弹性变形过程。方法:1.运用Burgers与四单元五参数粘弹性本构方程,拟合得到CA砂浆的时间硬化率特征参数,并验证该参数的合理性(图5);2.结合现场测试所得钢轨支点压力,统计分析得到有限元模型循环加载的幅值与周期(图11);3.通过仿真模拟,得到CA砂浆在列车荷载作用下、不同初始弹性模量时的粘弹性变形,进而探寻CA砂浆的粘弹性变形规律(图16和17)。结论:1.基于时间硬化率的分析模型能较好地模拟CA砂浆变形行为。2.随着CA砂浆初始弹性模量的增大,CA砂浆在粘弹性变形前后的应变差值逐渐减小,位移差值逐渐增大;位移差值集中于0.2~0.6mm,且变形敏感区域约为板端2.5个扣件间距。3.CA砂浆本身粘弹性特征引起的不可恢复变形是导致CA砂浆层与轨道板之间形成离缝的重要原因之一;在研究CA砂浆变形及损伤时,建议考虑CA砂浆粘弹性行为及其变形特征的不利影响。

关 键 词：China railway track system(CRTS) Ⅰ prefabricated slab track Cement and emulsified asphalt mortar(CA mortar) Initial Young’s modulus Viscoelastic deformation Time hardening law(THL) 

分 类 号：U213[交通运输工程—道路与铁道工程]