基于疲劳强度理论的超薄桥面铺装层裂缝扩展分析

Study on Crack Propagation of Ultra-thin Deck Pavement Based on Fatigue and Fracture Mechanics

以断裂力学为基础,借助有限元方法,建立了裂缝扩展的有限元计算模型。采用应力强度因子作为评价指标,分析了在对旧桥面铺装进行加铺时,旧铺装层已存在的裂缝对加铺层的影响;研究了在行车荷载和温度荷载的作用下,不同宽度的裂缝和不同的加铺层厚度对加铺层裂缝扩展的影响。研究表明,低温是引起裂缝扩展的主要因素;随着厚度的增加裂缝尖端的应力强度因子呈下降趋势,对于薄层铺装来讲,则需要较高的抗裂性。

Based on fracture mechanics,the crack propagation model was established with the finite element method.When bridge deck pavement repaving was conducted,the effect of pavement cracks on the overlay was analyzed in terms of stress intensity factor.The influence of cracks of different widths and different overlay thickness on the overlay crack propagation under the load and temperature stress was studied.Through the study,it was indicated that low temperature was the major factor for crack propagation.The thicker the overlay,the smaller the stress intensity factor of crack tip.A higher crack resistance was in need for ultra-thin bridge deck pavements.