循环动荷载下路基红粘土安定行为研究

Study on Shakedown Behavior of Subgrade Red Clay under Cyclic Loading

摘要: 本文根据设计改装的循环动单轴压缩试验，通过不同含水率、不同轴向应力水平、不同循环加载次数及不同应力加载路径的试验，研究路基红粘土的安定行为、迟滞行为以及塑性力学行为等。结合能量耗散的分析，探讨了路基土在循环动载荷作用下的力学行为发展规律，分析了影响循环荷载作用下路基红粘土力学行为的主要因素，从变形机理上探讨土的应力–应变关系以及塑性变形模式，能明确界定红粘土路基在循环荷载下的临界应力状态范围及所容许的塑性应变，可有效的预测路面随荷载次数累积的车辙，以减少因车辆所造成的车辙破坏，为红粘土路基改良及路面厚度设计提供参考依据，提升路面管理的效能。

Abstract: This paper describes the shakedown, hysteretic and plastic behavior of cohesive subgrade soil under cyclic loading. Based on the energy dissipation principle, the various mechanic behaviors of subgrade red clay are discussed by repeated loading test. The test was performed in various conditions of subgrade soil. Different moisture content, stress level, the number of repeated loading and stress path are taken into account during the test. According to the test results, the factors that contribute to various mechanic behaviors of subgrade soil are analyzed in detail. In addition, the study presents a discussion on stress-strain relation and plastic deformation model of subgrade red clay with deformation principle. The mechanism of permanent deformation is explained in light of shakedown and hysteretic behavior.