循环移动轮载下粗粒土路基填料永久变形特性及安定分析  

Permanent deformation characteristics and shakedown analysis of coarse-grained embankment materials under moving wheel loads

作　　者：郑可扬 肖源杰 王萌 王斌[4] 严金龙 陈晓斌[1,3] 叶新宇 ZHENG Keyang;XIAO Yuanjie;WANG Meng;WANG Bin;YAN Jinlong;CHEN Xiaobin;YE Xinyu(School of Civil Engineerings Central South University,Changsha,Hunan 410075.China;Guangdong Communication Planning and Design Institute Co.,Ltd.,Guangzhou,Guangdong 510507,China;Ministry of Education(MOE)Key Laboratory of Engineering Structures of Heavy Haul Railway j Changsha,Hunan 410075,China;North Yutian Line Unit,Chawu Track Division,Daqin Railway Co.,Ltd.,Tangshan,Hebei 064107,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]广东省交通规划设计研究院股份有限公司,广东广州510507 [3]重载铁路工程结构教育部重点实验室,湖南长沙410075 [4]大秦铁路股份有限公司茶坞工务段玉田北线路车间,河北唐山064107

出　　处：《岩石力学与工程学报》2020年第9期1930-1943,共14页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(U1734208);中国铁道科学研究院科技研究开发计划重大课题(2019YJ026);湖南省自然科学基金资助项目(No.2018JJ3658)。

摘　　要：针对常规的恒定围压动三轴试验仅能模拟路基土动应力场中的循环偏应力等不足,为更真实地反映移动轮载下路基土的长期变形性能和破坏机制,采用应力路径斜率、应力路径长度、最小平均主应力等变量的不同组合,模拟循环偏应力和循环围压耦合下的动态应力路径,开展基层和底基层粗粒土填料的一系列恒定围压和循环围压动三轴试验,探究不同动态应力路径下粗粒土路基填料轴向累积塑性应变随荷载循环作用次数的变化规律。针对已有安定状态判定准则未能准确界定永久变形行为不同阶段且未能考虑循环围压效应等不足,提出基于Savitzky-Golay滤波法的永久变形行为不同阶段划分方法,采用循环围压条件下永久变形试验结果对现有安定准则进行了改进,结果表明该新判定准则具有较好的准确性和普适性。Conventional repeated load triaxial(RLT) tests can only simulate the cyclic load pulsed vertically. In order to study long-term deformation and failure mechanisms due to moving wheel loads more realistically,a series of RLT tests with both constant and variable confining pressure levels were conducted on typical base and subbase unbound granular materials. Different realistic in-situ stress paths defined by stress path slope,stress path length and minimum mean principal stress were applied. The coupling effect of cyclic deviatoric and confining stress components on the accumulation of the axial plastic strain was explored. Considering that the existing shakedown criteria for permanent deformation behavior cannot accurately distinguish different stages of permanent deformation behavior and are established from traditional RLT tests with constant confining pressure,a new criterion was proposed to address such insufficiencies. The improved accuracy and applicability of the modified shakedown analysis method and its criteria were confirmed by the realistic stress path test results obtained in this study.

关 键 词：土力学 粗粒土填料 循环荷载 循环围压动三轴试验 永久变形 安定分析 

分 类 号：TU43[建筑科学—岩土工程]