摘要
对纵连板式无砟轨道进行单元化,有望从源头上控制温度效应过大引起的结构损伤,降低结构失稳风险,但需要在单元化过程中对轨道结构进行限位。借助数值仿真计算,研究植筋和扣压两种限位条件下不同单元节段长度的纵连板式无砟轨道温度变形和损伤。研究认为:在单元节段的两端,植筋比扣压更能有效控制轨道板纵向变形,而两种限位方式对板角变形的控制效果相差不大;层间纵向位移差的总体控制可由植筋方式实现,而在板角处采用扣压方式更佳。植筋后,单元节段长度对植筋孔的混凝土损伤几乎没有影响;扣压后,当整体温升低于5℃时,单元节段长度对板角的混凝土损伤几乎没有影响,而当整体温升大于5℃时,单元节段长度的影响显著。植筋后,受拉损伤先出现在植筋孔孔壁处,随着整体温升增高,损伤区域朝轨道板横向发展;扣压后,受压损伤最先出现在轨道板板底,随着整体温升增高,损伤区域逐渐向板表发展。两种限位条件对轨道板和CA砂浆之间界面损伤的影响差异显著,植筋时总离缝面积小于扣压,但扣压可有效控制板角处离缝。以3块轨道板为一个单元节段,并采取植筋限位方式控制轨道结构温度变形和损伤。
This paper presents a proposal to cut the longitudinally connected slab ballastless track structure into discrete units with a certain length so as to control the damage caused by excessive temperature rise and accordingly reduce the risk of instability of track structure.The temperature deformation of the unit track structure needs to be constrained by some measures.By two displacement-limiting measures such as planting rebar and installing pressing device,the temperature deformation and damage of longitudinally connected slab ballastless track with different segment lengths are investigated in a numerical way.Results show that for the longitudinal deformation of both ends of the segment,the effect of planting rebar is more obvious than that of installing pressing device.For the longitudinal deformation of the slab corner of the segment end,the effects of two displacement-limiting measures are very close;The planting rebar is better to overall control the relative longitudinal displacement between the track slab and the CA mortar layer,and the installing pressing device has control advantage at the slab corner.When the rebar is planted,the segment length has little influence on the concrete damage of the rebar holes;While the pressing device is installed,the influence of the segment length on the concrete damage of slab corner is small under the overall temperature lower 5 ℃,and becomes significant after the overall temperature rise over 5 ℃.After the rebar is planted,the tensile damage first appears at the wall of the rebar hole,and the damaged area expands laterally with the temperature rising.After the pressing device is installed,the compressive damage first appears on the bottom surface of the track slab.As the temperature rises,the damage area expands upwards to the top surface of the track slab.For the interface damage,the differences in the influence between the two displacement-limiting measures are remarkable.The total delamination area reduced by planting rebar measure is larger,while delamination at the slab corner is better controlled by the installing pressing device measure.The temperature deformation and damage are controlled by choosing 3 slabs as a segment and using planting rebar measures.
作者
林锦镇
蒋典佑
刘钰
孙晓丹
杨怀志
谷永磊
LIN Jinzhen;JIANG Dianyou;LIU Yu;SUN Xiaodan;YANG Huaizhi;GU Yonglei(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Key Laboratory of High-speed Railway Engineering of Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China;National Engineering Research Center of Geological Disaster Prevention Technology in Land Transportation,Chengdu 610031,China;Beijing-Shanghai High Speed Railway Co.,Ltd.,Beijing 100038,China)
出处
《铁道标准设计》
北大核心
2024年第2期45-51,共7页
Railway Standard Design
基金
中国国家铁路集团有限公司科技研究开发计划重大课题(K2020G007)
西南交通大学重点实验室工程实践项目(ZD2022010077)。
关键词
高速铁路
单元化
数值计算
纵连板式无砟轨道
限位条件
变形协调
high speed railway
discrete unit
numerical calculation
longitudinally connected slab ballastless track
displacement-limiting measure
deformation compatibility
