Permanent deformation is a potential distress that affects the functional characteristics of pavement. Subgrade soil might contribute to different levels of permanent deformation depending on traffic intensity. This paper assesses the stress ratio effects as well as compaction water content variation on permanent deformation of subgrade soil, presents some contributions to understanding the Shakedown concept in fine-grained soils and evaluates models for estimating soil plastic strain. Repeated load triaxial (RLT) tests were performed on lateritic sandy soil in order to obtain: permanent deformation and Shakedown parameters. Findings indicated a prevalence of stress ratio in permanent deformation for a specified compaction water content range (w_opt ± 1.5%). However, analysis of plastic strain rates showed that permanent deformation might be more influenced by compaction water content than by stress ratio, mainly in cases where compaction water content range is wider. Furthermore, stabilization, i.e. Shakedown first phase occurrence, was achieved under all test conditions, in spite of low deformation levels. Lastly, the model adjusted in function of stress ratio and compaction water content closely represented the complexity of soil plastic strain accumulation.

永久变形是影响路面功能特性的潜在困扰。路基土壤可能会导致不同程度的永久变形，具体取决于交通强度。本文评估了应力比的影响以及压实水含量变化对路基土壤永久变形的影响，为理解细粒土中的“减震”概念做出了贡献，并评估了估算土壤塑性应变的模型。为了获得：永久变形和减振参数，对红土砂土进行了重复载荷三轴（RLT）试验。结果表明，在规定的压实含水量范围内，永久变形中的应力比普遍存在（w _opt±1.5％）。然而，塑性应变率分析表明，永久变形可能受压实水含量的影响大于受应力比的影响，主要是在压实水含量范围较宽的情况下。此外，尽管变形水平较低，但在所有测试条件下均实现了稳定，即发生了第一阶段减振。最后，在应力比和压实含水率函数上进行了调整的模型非常接近于土壤塑性应变累积的复杂性。