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采用移动加载的动载模型,考虑轮胎花纹形式,选用非均布轮胎荷载模式,建立三维有限元路面结构模型分析了非均布移动荷载作用下含表面纵向和横向裂缝路面结构的应力响应,以探求移动荷载作用下表面裂缝的开裂机理。采用空间有限元——时间差分法对问题进行数值求解。分析过程中对裂缝尖端网格局部进行加密处理,并用位移法求取裂缝尖端的应力强度因子。分析得出随着荷载的移动,处于荷载正下方点位的裂缝Ⅰ型应力强度因子最大。移动荷载作用正下方纵缝的Ⅰ型应力强度因子的值均比静载时大,移动荷载可加速裂缝的开展。对于横缝随着荷载距离裂缝越近,对裂缝的影响越大。移动车辆荷载对纵向裂缝的影响比横缝更大。因此要特别注意路面表面纵向裂缝的预防和养护。
The dynamic loading model with moving load is adopted, the tire tread pattern is taken into account, the non-uniform tire loading mode is selected, and the three-dimensional finite element pavement structure model is established to analyze the stress response of pavement structure with longitudinal and transverse cracks under non-uniform distributed moving loads. Exploring Cracking Mechanism of Surface Cracks under Moving Loads. The problem is solved numerically by using space finite element method and time difference method. In the process of analysis, the crack tip mesh is partially encrypted, and the stress intensity factor of the crack tip is obtained by the displacement method. The analysis shows that with the movement of load, the type I stress intensity factor at the point just below the load is the largest. The value of type Ⅰ stress intensity factor of longitudinal seam just under the action of moving load is larger than that under static load, and the moving load can accelerate the crack initiation. For transverse joints with load distance closer to the cracks, the greater the impact on the cracks. The impact of moving vehicle loads on longitudinal cracks is greater than the transverse cracks. Therefore pay special attention to the prevention and maintenance of longitudinal cracks on pavement surface.