双块式无砟轨道轨枕与道床交界面损伤特性分析

The Characteristic Analysis of the Interface Damage of Double-Block Ballatless Track Sleeper and Track Bed

CRTS Ⅰ型双块式无砟轨道道床板为现浇混凝土部件结构,轨枕为预制结构部件,在新、旧混凝土交界处存在界面易开裂的问题。建立CRTS Ⅰ型双块式无砟轨道有限元模型,用cohesive内聚力单元模拟运营阶段轨枕与道床交界面,研究运营阶段在列车荷载和温度荷载作用下轨枕与道床交界面力学特性。结果表明:整体降温作用下,道床与轨枕交界面长边先出现损伤,并扩展到轨枕角处的交界面;交界面短边沿道床深度界面损伤逐渐变小,底部损伤只发展到轨枕角;在正温度梯度作用下,交界面主要不利受力区域为4个轨枕角及长边中上部区域,易出现损伤;在负温度梯度作用下,交界面长边受拉破坏,轨枕角交界面上部发生破坏;仅列车荷载作用下,不会造成界面破坏。

CRTS Ⅰ double-block ballatless track slab is cast-in-place concrete component structure,while sleeper is precast component structure.Therefore,the fracture often occurs in the interface of new and old concrete.The study establishes the finite element model of CRTS Ⅰ double-block ballatless track,simulates the interface of in-operation sleeper and track bed by using cohesive units,and looks into the mechanical property of sleep-track bed interface under the influence of train load and temperature load in operation.The results show that due to overall cooling,the damage appears in the long side of the interface of track bed and sleeper,then expands to the interface of sleeper angle;the interface damage of the short boundary along the deep interface of track bed gradually decreases,and the bottom damage only expands to the sleeper angle;in the effect of positive temperature gradient,the main unfavorable force regions of the interface are four sleeper angles and the middleupper part of the long side.They are easy to be damaged;under the action of negative temperature gradient,the long side of the interface is pulled down and the upper part of the sleeper corner is destroyed;the interface failure will not be caused by train load merely.