Current Japanese design guide uses mechanical-empirical criteria to predict the failure loading number against fatigue cracking and rutting. However, these criteria have some limitations that the variation in moduli of base and subgrade layer due to the fluctuation in water contents, freeze–thaw history, and stress states are not considered. As well known, these factors greatly affect the soil mechanical properties like resilient modulus. Besides, present rutting failure criterion provides no indication of the behavior of rutting over time, and the effect of principal stress axis rotation on rutting development is also not captured. To overcome such limitations, this study modified the present Japanese pavement design method through the following two main aspects: (1) Replacing constant elastic modulus of base and subgrade layer to resilient modulus related to stress states and complex climate conditions, which are defined as the combination of fluctuating water content and freeze–thaw action; (2) Modifying rutting failure criterion by considering generally used MEPDG model and also the effect of principal stress axis rotation. All modifications are performed based on laboratory element test like suction-controlled freeze–thaw triaxial test, which could simulate complex climate conditions, and multi-ring shear test, which could simulate principal stress axis rotation. Besides, modified criteria are examined by comparing to long-term measured performance of test pavements built in Hokkaido, the north island of Japan. Modified Japanese pavement design method shows high applicability and accuracy on the pavement life prediction, especially for the flexible pavement in cold regions like Hokkaido.

当前的日本设计指南使用机械经验标准来预测针对疲劳裂纹和车辙的失效载荷数。但是，这些标准存在一些局限性，即未考虑由于水含量波动，冻融历史和应力状态而引起的基础层和路基层模量的变化。众所周知，这些因素极大地影响了土壤的机械性能，例如弹性模量。此外，目前的车辙失效标准不能提供车辙随时间的行为的指示，也没有捕获主应力轴旋转对车辙发展的影响。为了克服这些限制，本研究通过以下两个主要方面修改了当前的日本路面设计方法：（1）将基层和路基层的恒定弹性模量替换为与应力状态和复杂气候条件相关的弹性模量，这些弹性模量被定义为水含量波动和冻融作用的组合；（2）通过考虑常用的MEPDG模型以及主应力轴旋转的影响来修改车辙破坏准则。所有修改均基于实验室元素测试（例如，抽吸控制的冻融三轴测试，可以模拟复杂的气候条件）和多环剪切测试（可以模拟主应力轴旋转）进行。此外，通过与在日本北岛北海道建造的试验路面的长期测量性能进行比较，对修改后的标准进行了检查。