钢筋非均匀锈蚀诱发无砟轨道混凝土轨道板开裂的分析

Cracking Analysis of Concrete Slab for Ballastless Track Induced by Non-uniform Corrosion of Reinforcement

钢筋锈蚀是导致沿海地区轨道板耐久性失效的主要因素之一。为探究钢筋非均匀锈蚀对高速铁路无砟轨道混凝土轨道板破坏的影响,建立了以锈蚀率、最大锈蚀层厚度及最小锈蚀层厚度为自变量的高斯型钢筋锈蚀层分布模型。基于键型近场动力学理论,通过在钢筋与混凝土交界面施加钢筋锈蚀位移荷载,模拟了钢筋锈蚀诱发轨道板开裂破坏过程,分析了钢筋非均匀锈蚀和保护层厚度对开裂形态的影响。结果表明:在轨枕下方的轨道板,钢筋锈蚀易引起轨道板发生钢筋间贯通性裂纹,而在轨道板中部,钢筋锈蚀导致混凝土保护层中产生贯穿性裂纹;在相同锈蚀率条件下,与均匀锈蚀相比,非均匀锈蚀诱发的轨道板损伤更加严重,因此在评估钢筋锈蚀对轨道板的影响时,须要考虑钢筋锈蚀的非均匀性。

Reinforcement corrosion is one of the main factors leading to durability failure of track slab in coastal areas.In order to explore the influence of non-uniform corrosion of reinforcement on the damage of concrete slab for ballastless track of high speed railway,a Gaussian distribution model of reinforcement corrosion layer was established by taking corrosion rate,maximum corrosion layer thickness and minimum corrosion layer thickness as independent variables.Based on the bond type peridynamics theory,the process of track slab cracking induced by reinforcement corrosion was simulated by applying the displacement load of reinforcement corrosion at the interface between reinforcement and concrete,and the influence of non-uniform corrosion of reinforcement and the thickness of protective layer on the cracking morphology was analyzed.The results show that the reinforcement corrosion of the track slab under the sleeper is easy to cause the through cracks between the reinforcements of the track slab,while in the middle of the track slab,the reinforcement corrosion causes the through cracks in the concrete protective layer.Under the same corrosion rate,compared with uniform corrosion,the track slab damage induced by non-uniform corrosion is more serious.Therefore,the non-uniformity of reinforcement corrosion must be considered for evaluating the influence of reinforcement corrosion on track slab.