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考虑路面各结构层不同的模量组合,建立不同路面结构的有限元模型,分析基层模量和底基层模量对于沥青面层层底拉应力和底基层层底拉应力的影响规律,并通过沥青路面抗疲劳开裂的经验公式,预测不同路面结构组合的沥青路面疲劳寿命,分别对沥青面层和基层合理的模量组合,以及底基层和路基模量匹配进行研究。结果表明:当面层与基层模量比值(E面层/E基层)小于1.8时,沥青面层疲劳寿命随E面层/E基层的增加迅速降低,E面层/E基层大于1.8时,面层疲劳寿命随E面层/E基层的增加缓慢降低,疲劳寿命预测值降为2.3万~160万轴次;底基层模量和路基模量比值(E底基/E路基)较低时,底基层疲劳寿命随E底基/E路基的增加迅速降低,E底基/E路基大于20∶1时,底基层疲劳寿命缓慢降低,疲劳寿命的预测值已经降低到200万标准轴载作用次数以下;通过考虑E面层/E基层和E底基/E路基的路面疲劳寿命等值线图,可以确定路面设计疲劳寿命对应的E面层/E基层和E底基/E路基的合理取值。
Considering the different modulus combination of each structural layer of pavement, the finite element model of different pavement structure was established. The influence of base modulus and base modulus on the tensile stress at the bottom of asphalt pavement layer and the tensile stress at the bottom of asphalt pavement layer was analyzed. Asphalt pavement fatigue cracking resistance of the empirical formula to predict the pavement structure of asphalt pavement fatigue life, asphalt layer and the grassroots reasonable modulus combinations, as well as the subbase and subgrade modulus matching research. The results show that the fatigue life of asphalt surface layer decreases rapidly with the increase of E surface layer / E base layer when the ratio of surface layer to base layer modulus (E surface layer / E base layer) is less than 1.8. When E surface layer / E base layer is greater than 1.8, The fatigue life of layer decreases slowly with the increase of E surface layer / E base layer, and the predicted value of fatigue life is reduced to 23000 ~ 1600000 axes. When the ratio of base layer modulus and subgrade modulus (E base / E subgrade) The fatigue life of the subbase rapidly decreases with the increase of E subbase / E subgrade. When the E subbase / E subgrade is greater than 20: 1, the fatigue life of the subbase slowly decreases and the prediction value of fatigue life has been reduced to 2 million standard axle load times . By considering the isometric fatigue life map of E-story / E-story and E-story / E subgrade, the rational design of E-story / E-story and E-subbase / E subgrade corresponding to the fatigue life of pavement design value.