CRTS-I型板式无砟轨道疲劳寿命研究

Research on Fatigue Life of CRTS-I slab Ballastless Track

为研究无砟轨道在列车荷载和环境温度共同作用下的疲劳特性,以CRTS-Ⅰ型板式无砟轨道为研究对象,建立弹性地基梁-体模型,计算出列车荷载和温度梯度作用下轨道结构的垂向最大应力,并结合普通混凝土结构S-N曲线的疲劳寿命分析方程和CA砂浆在不同温度时的疲劳方程,预测了CRTS-Ⅰ型板式无砟轨道各结构层在规定服役年限内的疲劳寿命。计算表明,对于有限的作用次数,CRTS-Ⅰ型板式无砟轨道各结构层受到的最大应力均未超过相应的混凝土强度值。根据各结构层最大应力预测出的相应疲劳寿命表明,CA砂浆在25~30年后将出现疲劳损伤,而在规定年限60年内,CRTS-Ⅰ型板式无砟轨道其他结构层不会出现疲劳损伤,能达到客运专线服役期内的要求。

To study the fatigue characteristics of the slab ballastless track under the joint action of the train load and the environment temperature,a beam structure model of elastic foundation is established to calculate the maximum vertical stresses of every track layer under the action of train load and environment temperature based on CRTS-I slab ballastless. In combination with S-N curve of ordinary concrete structure fatigue life analysis equation and fatigue equation of CA mortar at different temperatures,the fatigue life of every structure layer of CRTS-I slab ballastless track within regular service period is predicted. Calculation results show that the maximum bearing stress of every track layer of CRTS-I slab ballastless track doesn＇t exceed corresponding concrete strength within limited number of action. The corresponding fatigue life of all structural layers predicted according to the maximum stresses shows that the fatigue damage of CA mortar appears only after 25 ~ 30 years,and other layers of CRTS-I slab ballastless track will not experience fatigue damage within the prescribed period of 60 years,which meet the need for dedicated passenger line service life.