重复荷载作用下粉性路基土累积塑性变形研究

发布时间：2018-04-21 07:51

本文选题：粉性路基土 + 动三轴试验　；参考：《岩土力学》2014年12期

【摘要】：为研究不同含水率、压实度和应力水平下路基压实粉性路基土累积塑性变形影响因素与变化规律,开展了系列动三轴试验。根据累积塑性应变随加载次数的变化规律,获得了不同含水率、压实度下粉土的临界动应力。研究表明,粉性路基土临界动应力随压实度的提高而增大,随含水率的增大而减小。为避免路面结构的破坏,路基土应力状态应控制在临界应力界限范围内。鉴于此,针对路基土临界应力范围内的试验数据,建立了路基土累积塑性变形预估模型。该模型考虑了应力和加载次数的影响。回归分析表明,该模型具有较高的决定系数,即模型具有较高的合理性与可靠性。模型的建立为基于力学经验法的路基累积塑性变形计算提供了参数。最后以典型水泥混凝土路面为例,获得了不同轴载、轴型作用下粉土路基累积塑性变形,为进一步研究路基累积塑性变形对路面结构的影响提供了思路。
[Abstract]:A series of dynamic triaxial tests were carried out to study the influence factors and variation rules of cumulative plastic deformation of silty subgrade soil under different moisture content compaction degree and stress level. According to the variation of cumulative plastic strain with loading times, the critical dynamic stress of silty soil with different moisture content and compaction is obtained. The results show that the critical dynamic stress of silty subgrade soil increases with the increase of compaction and decreases with the increase of moisture content. In order to avoid the damage of pavement structure, the stress state of subgrade soil should be controlled within the limit of critical stress. Based on the experimental data of subgrade soil in the critical stress range, a model for predicting the cumulative plastic deformation of subgrade soil is established. The model takes into account the effects of stress and loading times. The regression analysis shows that the model has high determinant coefficient, that is, the model has high rationality and reliability. The establishment of the model provides parameters for the calculation of cumulative plastic deformation of roadbed based on mechanical empirical method. Finally, taking typical cement concrete pavement as an example, the cumulative plastic deformation of silt subgrade under different axial load and axial type is obtained, which provides a train of thought for further studying the influence of accumulated plastic deformation of roadbed on pavement structure.
【作者单位】：中南大学土木工程学院;湖南省交通科学研究院;中南林业科技大学土木工程与力学学院;
【基金】：国家自然科学基金重点项目(No.U1361204) 交通部西部交通建设科技项目(No.2011 318 785 760,No.2009 318 785 104)
【分类号】：U416.1

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