沥青路面多裂纹断裂分析

Fracture Analysis of Asphalt Pavements with Multiple Cracks Based on the Coupled EFG and FE Method

沥青路面通常在表面裂纹和基础裂纹共存状况下服务。基于断裂力学理论,采用无网格伽辽金/有限元耦合法,对同时含有面层表面裂纹和基层底面裂纹的沥青路面进行了断裂分析,研究了行车荷载行驶过程中裂纹尖端应力强度因子的变化规律。结果显示,在车轮荷载行驶通过基层底面裂纹上方的过程中,基层底面裂纹的复合型应力强度因子K*存在一个最大极值,且这个最大值不是出现在车轮荷载位于基层正上方的时候;表面裂纹的应力强度因子K1和K2随着交通荷载驶近表面裂纹而逐渐增大,而且增大的速率也逐渐上升;相对于基层底面裂纹,表面裂纹受荷载位置影响更显著。

Asphalt pavements usually serve with both asphalt overlay crack and base crack. The fracture analysis of asphalt pavements with both cracks is done to investigate the rule of the stress intensity factor （SIF） at crack tips based on fracture mechanics by using the coupled element free Galerkin （EFG） and finite element （FE） method. The results show that mixed-mode SIF at the base crack tip exits an maximal extremum at the process that wheel loads moving over across the base crack, futhermore, this extremum is not produced when the load is right over the base crack; the mode Ⅰ and mode Ⅱ of SIFs at the overlay crack ascend in an increscent rate with wheel load moving close the overlay crack; the SIF at the overlay crack is more sensitive to the position of wheel load than that at the base crack.