粒料层当量模量求解新方法——以粒料基层沥青路面为例  

Method for Determining Equivalent Modulus of Granular Layer--A Case Study of Asphalt Pavement with Granular Base

作　　者：黄优 王帅[1,2] 刘朝晖 张允宝[3] 柳力 HUANG You;WANG Shuai;LIU Zhao-hui;ZHANG Yun-bao;LIU Li(Engineering Research Center of Catastrophic Prophylaxis and Treatment of Road&Traffic Safety of Ministry of Education,Changsha University of Science&Technology,Changsha 410114,Hunan,China;School of Traffic and Transportation Engineering,Changsha University of Science and Technology,Changsha 410114,Hunan,China;Department of Transportation of Hunan Province,Changsha 410116,Hunhan,China)

机构地区：[1]长沙理工大学道路灾变防治及交通安全教育部工程研究中心,湖南长沙410114 [2]长沙理工大学交通运输工程学院,湖南长沙410114 [3]湖南省交通运输厅,湖南长沙410116

出　　处：《中国公路学报》2023年第2期97-106,共10页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52008044,52278437);湖南省自然科学基金项目(2022JJ40479);湖南省教育厅自然科学基金优秀青年基金项目(21B0296);湖南省交通运输厅科技进步与创新项目(202236);长沙理工大学道路灾变防治及交通安全教育部工程研究中心开放基金项目(kfj210401)。

摘　　要：为了给沥青路面合理设计提供参考,围绕粒料的非线性特性对粒料层当量模量展开研究。基于Uzan三参数模型编制材料子程序,并引入Cary&Zapata模型对粒料回弹模量进行湿度调整;利用有限元方法开展不同温湿度组合下的沥青路面非线性结构计算;自主开发迭代反演算法,提出基于关键结构响应(沥青层底最大拉应变等效)的粒料层当量模量求解新方法,并结合当前基于路表弯沉的结构层反算模量进行比较分析。结果表明:①由于粒料的非线性,路表弯沉等效并不意味着内部关键结构响应等效,采用基于路表弯沉的线弹性模量反算体系对具有明显非线性的粒料层模量进行求解,存在不合理性;②自主开发的基于关键结构响应等效的粒料层当量模量求解方法快速稳定,沥青面层底部最大拉应变的相对误差可控制在1%之内;③以层状弹性体系为理论基础的沥青路面设计方法忽略了粒料层的非线性,造成荷载传力路径与真实情况存在偏差,使得实际弯沉(非线性)大于计算弯沉(线弹性),从理论上论证了中国当前“柔性基层沥青路面弯沉验收难以通过”的现实困境;④基于关键结构响应的当量模量与当前基于路表弯沉的反算模量之间存在良好的相关性,提出了二者的转换模型Eeq=a*E^(b),后续将进一步探讨2种模量之间的协调与统一。研究可为完善沥青路面设计理论与粒料的推广应用提供参考。In this study,the equivalent modulus of a granular layer was investigated based on the nonlinear property of the granular material to provide a reference for designing granular layers.A user-defined material subroutine based on the Uzan three-parameter model was programmed.The Cary and Zapata model was incorporated for moisture adjustment,and nonlinear structural analyses under different environmental conditions were conducted using the finite element method.A new method was developed to determine the equivalent modulus based on the critical response,and the proposed method was evaluated using a self-developed iterative algorithm,which was comprehensively compared and evaluated with the current modulus back-calculation process based on the surface deflection basin.The results show the following.①The equivalence of the surface deflection does not indicate the equivalence of the internal structural response because of the nonlinearity of the granular layer.The linear-elastic-modulus back-calculation system based on surface deflection does not function satisfactorily for the significantly nonlinear granular layer.②The self-developed method for calculating the equivalent modulus based on the critical response is fast and stable,with the difference in the horizontal strain at the bottom of the asphalt layer between the linear and nonlinear analyses less than 1%.The proposed method is suitable for the current pavement design and evaluation system.③The asphalt pavement design based on the layered elastic theory ignores the nonlinearity of the granular material,which changes the load stress distribution within the pavement structure,making the actual surface deflection(nonlinear)always larger than the calculated surface deflection(linear).Thus,the current dilemma that“the surface deflection of flexible base asphalt pavement is difficult to pass the specification”in China is theoretically explained.④The equivalent modulus based on the critical response proposed in this study has an excellent relationship with

关 键 词：道路工程 粒料层 有限元方法 当量模量 关键结构响应 非线性 

分 类 号：U416[交通运输工程—道路与铁道工程]