In this paper,based on the theory of fracture mechanics,fracture mechanics parameters was calculated directly by using the finite element analysis method,to determine the temperature gradient and traffic load,etc.The influence of semi rigid pavement reflection crack at the grass-roots level.The results show that through crack is easy to cause crack tip to appear stress concentration at the grass-roots level,and are more likely to cause reflection cracks under partial load and extension;Half dry pavement reflection crack under traffic load at the grass-roots level is to accelerate the extension;Reflected in the process of crack propagation at the grassroots level alone under the traffic load,the crack tip stress field is affected by the surface of the thickness,modulus,separate under temperature load,the crack tip stress field surface modulus,the influence of temperature shrinkage coefficient at the grass-roots level;When the traffic load and temperature load,the crack tip stress field joint decision there are two kinds of load,and low temperature shrinkage stress can effectively reduce the traffic load caused by shear stress intensity factor.%在断裂力学的理论基础上,运用有限元分析法直接计算断裂力学参数,确定温度梯度和交通荷载等对半刚性基层路面反射裂缝的影响.研究结果表明:基层贯通裂缝容易造成裂缝尖端出现应力集中,且偏荷载作用下更易造成反射裂缝产生和扩展;半干性基层路面反射裂缝在交通荷载作用下是加速扩展的;基层反射裂缝扩展过程中,单独交通荷载作用下,裂缝尖端应力场受面层的厚度、模量的影响,单独温度荷载作用下,裂缝尖端应力场面层模量、基层温缩系数的影响;当交通荷载和温度荷载共同作用时,裂缝尖端应力场有两种荷载共同决定,且低温收缩应力能有效降低由于交通偏载造成的剪切型应力强度因子.
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