双块式无砟轨道连续道床板表面裂纹失稳扩展研究.docVIP

  双块式无砟轨道连续道床板表面裂纹失稳 扩展研究# 任娟娟1，黄慧超1，郝远行2，林红松2* 5 10 15 （1. 西南交通大学高速铁路线路工程教育部重点实验室，成都 610031； 2. 中铁二院工程集团有限责任公司，成都 610031） 摘要：为研究连续道床板上表面裂纹失稳扩展情况，基于断裂力学理论，以 CRTS I 型双块 式无砟轨道结构为例，通过建立含 50cm 表面裂纹的连续双块式无砟轨道有限元模型，分析 了轨道分别在降温 50以及负温度梯度为 45/m 时表面裂纹在不同深度时的失稳扩展长 度。结果表明：在整体降温荷载作用下，当裂纹深度小于 30mm 时，表面裂纹不会发生失稳 扩展；当表面裂纹深度超过 30mm 时，随着裂纹深度的增加，裂纹失稳扩展长度随之减小， 且减小幅度明显变缓;在负温度梯度荷载作用下，当其深度小于 100mm 时，裂纹不会沿道床 板横向失稳扩展，当深度大于 150mm 时，随着裂纹深度的增加，裂纹失稳扩展长度随之减 小。 关键词：连续道床板;表面裂纹;失稳扩展;整体降温;温度梯度 中图分类号：U216 文献标识码:A  Crack Propagation of Surface Crack on Continuously 20 25 30 35 40 Reinforced Slab for Twin-block Slab Track REN Juanjuan1, HUANG Huichao1, HAO Yuanxing2, LIN Hongsong2 (1. MOE Key Laboratory of High-speed Railway Engineering, Southwest Jiaotong University, Chengdu 610031, China; 2. China Railway Eryuan Engineering Group CO.LTP, Chengdu 610031, China) Abstract: Based on the fracture mechanics theory, an example of CRTS I Twin-block Slab Track structure is presented to investigate the crack propagation on the continuously reinforced slab surface. For the study, a finite element model of surface crack with the depth of 50cm on the continuously reinforced concrete slab has been established. The critical value of the unstable crack propagation of surface crack with different depths on the concrete slab has been analyzed, under a temperature drop of 50℃ and a negative temperature gradient of 45℃/m, respectively. The results indicate that: with the reduction of slab temperature, there is no unstable propagation for crack when the surface crack depth is less than 30mm, while the critical value of unstable crack propagation decreases with the increasing crack depth when the crack is deeper than 30mm, and meanwhile, the rate of reduction tend to be inversely proportional to the increasing crack depth. It is also obtained that under the negative temperature gradient load, crack will not propagate transversely when the surface crack depth is less than 100mm, however, crack will propagate and