Practical assessment of subgrade settlement induced by train operation requires developing suitable models capable of describing permanent deformation characteristics of subgrade filling under repeated dynamic loading. In this paper, repeated load triaxial tests were performed on coarse-grained soil (CGS), and the axial permanent strain of CGS under different confining pressures and dynamic stress amplitudes was analysed. Permanent deformation behaviors of CGS were categorized based on the variation trend of permanent strain rate with accumulated permanent strain and the shakedown theory. A prediction model of permanent deformation considering stress state and number of load cycles was established, and the ranges of parameters for different types of dynamic behaviors were also divided. The results indicated that the variational trend of permanent strain rate with accumulated permanent strain can be used as a basis for classifying dynamic behaviors of CGS. The stress state (confining pressure and dynamic stress amplitude) has significant effects on the permanent strain rate. The accumulative characteristics of permanent deformation of CGS with the number of load cycles can be described by a power function, and the model parameters can reflect the influence of confining pressure and dynamic stress amplitude. The study’s results could help deepen understanding of the permanent deformation characteristics of CGS.

由列车运行引起的路基沉降的实际评估需要开发合适的模型，该模型能够描述反复动态载荷下路基填土的永久变形特征。本文对粗粒土（CGS）进行了反复荷载三轴试验，分析了不同围压和动应力幅值下CGS的轴向永久应变。基于永久应变率随累积永久应变的变化趋势和振动理论对CGS的永久变形行为进行了分类。建立了考虑应力状态和载荷循环次数的永久变形预测模型，并划分了不同类型动态行为的参数范围。结果表明，永久应变率随累积永久应变的变化趋势可作为CGS动态行为分类的依据。应力状态（限制压力和动态应力幅度）对永久应变率具有重要影响。CGS的永久变形随载荷循环次数的累积特征可以用幂函数来描述，模型参数可以反映围压和动应力幅值的影响。研究结果可能有助于加深对CGS永久变形特征的理解。应力状态（限制压力和动态应力幅度）对永久应变率具有重要影响。CGS的永久变形随载荷循环次数的累积特征可以用幂函数来描述，模型参数可以反映围压和动应力幅值的影响。研究结果可能有助于加深对CGS永久变形特征的理解。应力状态（限制压力和动态应力幅度）对永久应变率具有重要影响。CGS的永久变形随载荷循环次数的累积特征可以用幂函数来描述，模型参数可以反映围压和动应力幅值的影响。研究结果可能有助于加深对CGS永久变形特征的理解。