基于应变的路基工作区深度及其影响因素分析

Analysis of Subgrade Influence Depth and Its Influencing Factors Based on Strain

应用有限元软件ABAQUS,建立了一典型柔性沥青路面结构三维有限元模型,通过分析路基应力应变沿深度的分布,提出了基于应变的路基工作区深度判定标准,对比了基于应变和应力的路基工作区深度和相应的永久变形,进一步分析了汽车轴载、路基模量等因素对基于应变的路基工作区深度的影响规律.结果表明,以附加应变与自重应变之比为0.1作为路基工作区深度的判定标准较为合理;在相同的作用荷载下,基于应变标准的路基工作区深度比基于应力标准的工作区深度大0.21~0.35m,相应的永久变形大0.14~0.28mm;在作用荷载相同时,路基工作区深度随路基模量的增加而增大;在路基模量相同时,超载时路基工作区深度具有较大幅度增加,同时,多轴荷载作用的叠加效应对路基工作区深度也有显著影响.

A 3D finite element model for a typical flexible asphalt pavement was established using ABAQUS. By analyzing the stress and strain distribution along the subgrade depth, a new judgment standard for the determination of subgrade influence depth based on strain index was presented, and the comparisons of the subgrade influence depths and the corresponding subgrade permanent deformations based on strain index and stress index were addressed as well. Furthermore, the effect of load- ing, subgrade modulus on the subgrade influence depths based on strain index were analyzed. The results indicate that it is reasonable to apply the ratio of additional strain to weight strain as the judg- ment standard for the determination of the subgrade influence depth when the value of the ratio rea- ches 0.1; Under the same loading, the subgrade influence depths based on strain judgment standards are 0.21-0.35 m more than those based on stress judgment standards, and the corresponding subgrade permanent deformations are 0.14-0.28 mm more and the subgrade influence depths increase with subgrade modulus. In the same subgrade module, the subgrade influence depths increase consid- erably under overloading, and the multiple load configurations also have a significant impact on the subgrade influence depths.