MECHANICAL ANALYSIS AND EVALUATION OF GRANULAR MATERIALS IN PAVEMENT STRUCTURES

在路面结构中，颗粒材料层的结构质量一直不高。本课题旨在发展路面结构中颗粒材料的分析与评价新方法。为此，研究人员被分为五组，并在这些组之间进行合作研究。各组结果如下：括号中的姓名为研究者：A组。建模颗粒基层（Nishizawa）：开发了基于三维有限元分析的路面结构分析软件包Pave3D。将B组开发的扩展SMP标准修正Cam-clay模型纳入到Pave3D中。利用该模型，对混凝土路面中颗粒基的永久变形效应进行了研究。研究发现，基层的永久变形显著增加了混凝土应力。更颗粒材料（Koyanagawa, and Takeuchi）的力学行为建模：通过重复加载试验证实了混凝土板下基层存在永久变形。然后，为了将扩展SMP准则修正的Cam-clay模型应用于颗粒材料，对颗粒基层材料进行了三轴压缩试验，确定了模型所需的参数。c组：颗粒材料的微观力学（Murai）：采用二维光弹试验对颗粒材料在压缩和剪切试验下的应力传递路径进行了可视化研究。在此基础上，研究了级配对应力传递路径的影响。d组颗粒基层施工改进（八屋）：采用水泥稳定再生沥青混凝土开发新型基层材料。研究了含水率、压实度和厚度对施工的影响。结果表明，如果压实足够，含水量的影响很小。E.颗粒基层结构评价（Kamiura）：为了准确评价颗粒基层的力学性能，对致密FWD和PS层检法的适用性进行了检验。结果表明，两种方法均可用于评价，且两种方法之间的差异很小。少

Granular material layers have not been considered to have high structural quality in pavement structures. The object of this project is to develop new analysis and evaluation methods of granular materials in pavement structure. For this purpose, the investigators have been divided into five groups and conducted their studies in collaboration among these groups. Outcomes of each group are as follows. Name(s) in parenthesis is(are) investigator(s) :Group A. Modeling granular base course (Nishizawa) : A program package for structural analysis of pavement based on three dimensional finite element analysis, Pave3D was developed. Extended SMP Criterion Modified Cam-clay model, which was developed by Group B, was incorporated into the Pave3D. Using the model, effects of permanent deformation of granular subbase in a concrete pavement was investigated. It was found that the permanent deformation of base course significantly increases concrete stresses.Group B. Modeling mechanical behavior of g … More ranular material (Koyanagawa, and Takeuchi) : Existence of permanent deformation of base course under concrete slab was confirmed from a repetitive loading experiment. Then to apply the Extended SMP Criterion Modified Cam-clay model to granular materials, triaxial compression test was conducted on a granular base course material and parameters required for the model were identified.Group C. Micro-mechanics of granular material (Murai) : Visualization of stress transfer path in granular material under compressive and shear tests was tried using the two dimensional photo-elastic test. From the results, effect of gradation on stress transfer path was investigated.Group D. Improvement of construction of granular base course (Hachiya) : New base course material was developed using reclaimed asphalt concrete stabilized with cement. Also, effects of water content, compaction degree and thickness on construction were investigated. The results revealed that the effect of water content is very small if compaction is sufficient.Group E. Structural evaluation of granular base course (Kamiura) : In order to precisely evaluate mechanical property of granular base course, applicability of compact FWD and PS layer inspection method were examined. It was found that both methods can be used for the evaluation and the difference between those two methods is very small. Less