温度荷载和车辆载荷作用下CRTS Ⅲ无砟轨道板损伤分析

Damage Analysis of the CRTS Ⅲ Ballastless Track Slab Under Temperature Load and Vehicle Load

基于混凝土损伤塑性模型建立了CRTSⅢ型板式无砟轨道有限元模型,模拟了日温荷载作用下轨道板的损伤演化行为,以及日温荷载和高速车辆动荷载作用下轨道板的损伤行为,对比了车辆荷载作用下有、无损伤时轨道板的动力响应.结果表明,降温导致轨道板上表面的拉应力超过混凝土抗拉极限时,上表面中心处的损伤因子和刚度退化系数快速增长,轨道板产生不可恢复的损伤行为;温度回升后,轨道板的刚度退化系数逐渐减小至零,但损伤因子仍保持在最高值;当车辆通过有损伤的轨道时,扣件支点处轨道板的刚度退化系数变化很小,车辆荷载没有明显加剧轨道板损伤,但有损伤轨道板的垂向振动位移和振动加速度较无损伤轨道板显著增大.

Based on the concrete damage plastic model,the finite element model of CRTS Ⅲ slab ballastless track was established to simulate the damage evolution behavior of the track slab under daily temperature loads.Moreover,the damage behavior of the track slab under the daily temperature load and the high-speed vehicle dynamic load was simulated,and the dynamic response of the track slab with and without damage under the vehicle load was compared.The results show that when the tensile stress on the upper surface of the track slab exceeds the tensile limit of concrete due to cooling,the damage factor and stiffness degradation coefficient at the center of the upper surface increase rapidly,resulting in irreversible damage behavior of the track slab.After the temperature rises,the stiffness degradation coefficient of the track plate gradually decreases to zero,but the damage factor remains at the highest value.When the vehicle passes through the damaged track,the stiffness degradation coefficient of the track plate at the pivot of the fastener changes very little,and the vehicle load does not significantly aggravate the track plate damage.However,the vertical vibration displacement and vibration acceleration of the damaged track plate increase significantly compared with the non-damaged track plate.