中文摘要：

随着基础设施建设的不断发展，半刚性基层材料在道路建设中得到不断推广使用，但早期裂缝的出现，严重影响了道路的使用寿命。针对半刚性基层路面，为了探明裂缝自身三维尺度的变化对路面结构疲劳寿命的影响，采用断裂力学理论并以应力强度因子为计算指标，利用Ansys有限元软件进行路面的数值模拟，得到了裂缝三维尺度对应力强度因子的影响规律，同时利用Matlab软件将得到的应力强度因子分别对裂缝三维尺度进行函数拟合并运用Paris公式计算裂缝扩展的疲劳寿命。结果表明：应力强度因子中对裂缝三维变化最为敏感的都是剪切型应力强度因子K2；按照裂缝的三维对应力强度因子的增长起的有效作用大小可以排列为宽度〉长度〉高度；随裂缝高度上限的增加，其疲劳寿命近似直线增长；为了保证带隐含裂缝的半刚性路面结构在设计年限内的正常工作，对长度〉0．2m、宽度〉o．035m、高度〉0．003m的裂缝进行修补，能有效阻止裂缝的进一步发展，而长度〉0．3m、宽度〉0．045m、高度〉0．003m的裂缝必须进行处理。因此，运用探地雷达等无损检测技术检测隐含裂缝时，要求其检测精度至少能够达到0．005m左右。

英文摘要：

With the continuous development of the infrastructure construction, the semi-rigid base materials have been widely used in road construction. However, the emergence of early crack has a great influence on the bearing capacity of the road. It will also impose the serious influence on the fatigue life of the road. This paper has a study on the fracture life of semi-rigid base pavement and finds out that three dimensional scale of cracks impacts on fatigue life of semi-rigid base pavement. This paper adopts the theory of fracture mechanics and the stress intensity factor is calculating index. Numerical simulation of the pavement is calculated by using the finite element software ANSYS. The influence law of the 3- dimensional scale of cracks which impact on the stress intensity factor can be obtained. At the same time, the stress intensity factor of crack respectively fits function with the 3-dimensional scale by MATLAB. The fatigue life of crack propagation can be obtained by the Paris formula. The results show that the most sensitive stress intensity factor is shear stress intensity factor K2 among the stress intensity factors which are influenced by 3-dimensional scale of cracks. The three dimensional scale of the crack in accordance with the effective role on the growth of the stress intensity factor is width 〉 length 〉 height. With the increasing of the upper limit of the crack height, its fatigue life of the growth is similar linear. In order to keep semi-rigid pavement structure with concealed crack in the normal work of the design period, when the length of the crack is greater than 0.2 m, the width of cracks is greater than 0. 035m and the height of the cracks greater than 0. 003m, the crack repair can effectively prevent the further development of the crack. When the length of the crack is greater than 0.3 m, the width of cracks is greater than 0. 045m and the height of the cracks greater than 0. 003m, the crack has to be repaired. As a result, when nondestructive testing technology such as ground penet