温度梯度作用下既有离缝无砟轨道结构层间损伤扩展及变形分析

Analysis of Interlayer Damage Propagation and Deformation of Existing Delamination Ballastless Track Structure under Temperature Gradient

为探讨温度荷载作用下既有离缝无砟轨道结构层间损伤发展规律及上拱变形对轨道结构力学特性的影响,基于有限单元法和界面损伤内聚力模型,建立CRTSⅡ型板式无砟轨道有限元模型。计算结果表明:温度梯度荷载作用下,层间损伤萌生于离缝区与黏结区衔接处板角位置,并随温度梯度的持续增大斜向发展;黏结区损伤横向贯通后,轨道板竖向位移存在明显突变;正温度梯度荷载作用更易引起既有离缝轨道板整板脱黏;轨道板上拱导致端部0.1~0.2 m存在明显黏结弱化区;小波长、大幅值形式的轨道板上拱更易引起轨道板开裂。

In order to explore the interlayer damage development law of the existing delamination ballastless track under temperature load and the influence of the upper arch deformation on the mechanical properties of the track structure,a CRTSⅡslab ballastless track finite element is established based on the finite element method and the interface damage cohesion model.The calculation results show that under the action of the temperature gradient load,the interlaminar damage originates at the corner position of the joint between the delamination zone and the bonding zone,and develops obliquely with the continuous increase of the temperature gradient;the vertical displacement of track slab changes abruptly after the transverse penetration of the bonding zone;the positive temperature gradient load is more likely to cause debonding of the existing delamination track slab;the arch of the track slab leads to an obvious bond weakening zone in the range of 0.10~0.20 m at the end;track slab arches with small wavelength and large amplitude are more likely to cause track slab cracking.