高速铁路隧道线路底部结构累积疲劳损伤特性分析

Analysis on Cumulative Fatigue Damage Characteristics for the Bottom Structure of High-speed Railway Tunnel Line

利用侧向双轴拉-压疲劳损伤力学模型,建立隧道线路底部结构疲劳寿命分析方法。基于MIDAS GTS NX三维有限元分析平台,以武广高速铁路某双线隧道线路结构为研究对象,建立围岩-隧道衬砌结构-线路底部结构动力相互作用分析模型,研究隧道线路底部结构轨道板、混凝土支承层以及仰拱填充层动力响应特征与疲劳损伤寿命。研究结果表明,高速列车振动荷载在隧道线路底部结构内产生的动应力属于侧向双轴拉-压应力状态;隧道线路普通段底部结构疲劳寿命主要取决于轨道板,其疲劳寿命满足设计使用年限要求,而隧道端部线路底部结构的疲劳寿命则同时取决于轨道板和仰拱填充层,其疲劳寿命均少于60 a,达不到线路设计使用年限要求;隧道端部线路底部结构是隧道使用寿命设计的关键性控制因素。

By using the fatigue damage mechanics model under lateral biaxial tension and compression, an analysis method of cumulative fatigue life is presented for the bottom structure of high-speed railway tunnel line. Then,based on MIDAS GTS NX 3D finite element analysis platform,a dynamic analysis model is established according to the bottom structure of a double tunnel lines on Wuhan-Guangzhou high-speed railway. The model is used to study the dynamic response characteristics and fatigue life on the bottom structure of turmel line, such as the track slab,concrete supporting layer and the filling layer of invert. The research results show that the dynamic stress in the bottom structure of tunnel line caused by the vibration loadings of high- speed train belongs to the lateral biaxial tension and compression stress. The fatigue life of the bottom structure depends mainly on the track plate, it should meet the requirements of design service life. But the fatigue life of the bottom structure at the end of tunnel line depends on the track plate and the filling layer of invert, the fatigue life of both are less than 60 years,can not meet the requirements of the designed service life. So, the bottom structure at the end of tunnel line becomes the key factor to control the tunnel life design.