湿化作用下高速公路红黏土路基动力特性现场试验  

Field Test Study on Dynamic Characteristics of Lateritic Soil Expressway Subgrade Under Wetting Action

作　　者：冯学茂 黄轩嘉 刘维正[1,3] 滕继东 谢治[1] FENG Xue-mao;HUANG Xuan-jia;LIU Wei-zheng;TENG Ji-dong;XIE Zhi(School of Civil Engineering,Central South University,Changsha 410075,Hunan,China;Guangxi New Development Transportation Group Co.Ltd.,Nanning 530029,Guangxi,China;National Engineering Research Center of High-speed Railway Construction Technology,Changsha 410075,Hunan,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]广西新发展交通集团有限公司,广西南宁530029 [3]高速铁路建造技术国家工程研究中心,湖南长沙410075

出　　处：《中国公路学报》2024年第6期169-180,共12页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52078500);中国中铁股份有限公司科技研究开发计划项目(2021-专项-08)。

摘　　要：为研究湿度变化下高速公路红黏土路基的动力响应和累积变形特性,依托南湛高速公路试验段开展了不同轴重、车速和路基湿度条件下的行车试验以及不同激振力、振动次数和路基湿化条件下的激振试验,分析路基动应力、动加速度、动位移的变化规律,揭示了动力特性沿路基深度和横向的衰减特征以及路基的累积变形规律。研究结果表明:路基浸水显著减弱路基对动应力、动加速度和动位移的衰减能力,导致动力响应和累积变形增加,含水率增加2.8%和4.2%时,动力响应分别增加7%和13%,累积变形分别增加28%和54%;动应力、动加速度和动位移的增长趋势与轴重、车速和激振力呈正相关,而路基动力响应影响距离沿远离荷载中心的方向呈现指数型衰减,在距离路床顶1.3 m处,动力响应衰减率可达80%;车辆有效影响深度随路基湿度、轴重和车速增加而增大,且轴重对路基的影响明显高于路基湿度和车速的影响程度,轴重分别为10、20和30 t时,有效影响深度分别为1.3、2.3、3.3 m;路基累积变形量随着路基湿度和振动次数的增加呈现快速增加后逐渐稳定的趋势,湿化1次和湿化2次后路基的累积变形量分别为湿化前路基的1.46和1.86倍,相同湿度条件下,前100万次累积变形占比达60%。研究成果可为高速公路改良红黏土路基的服役性能评价提供参考。In this study,the dynamic response and accumulative deformation characteristics of expressway lateritic soil subgrade were investigated under varying moisture contents by performing vehicle and vibration tests on a section of the Nanzhan expressway.Different axle loads,vehicle speeds,and subgrade wetting conditions were considered in the vehicle test,and different excitation forces,times,and subgrade wetting conditions were considered in the vibration tests.Moreover,the variation laws of the dynamic stresses,dynamic accelerations,and dynamic displacements of the subgrade were analyzed,and the accumulative deformation and the attenuation of dynamic characteristics along the depth and transverse directions of the subgrade were determined.The results show that subgrade immersion significantly reduces the attenuation ability of the subgrade to dynamic stress,dynamic acceleration,and dynamic displacement,leading to an increase in the dynamic response and accumulative deformation.When the moisture content increases by 2.8%and 4.2%,the dynamic response increases by 7%and 13%,respectively,and the accumulative deformation increases by 28%and 54%,respectively.The dynamic stress,dynamic acceleration,and dynamic displacement also increase with increasing axle load,vehicle speed,and excitation force,whereas the influence distance of the dynamic response of the subgrade exhibits an exponential attenuation along the direction away from the action point of the dynamic load.Moreover,the attenuation rate of the dynamic response can reach 80%at a distance of 1.3 m from the roadbed surface,and the effective influence depth of the subgrade increases with an increase in the moisture of the subgrade,axle load,and vehicle speed.The influence of the axle load on the subgrade is also significantly higher than that of the moisture of the subgrade and vehicle speed at an axle load of 10 t,20 t,and 30 t,respectively,and effective influence depth of 1.3 m,2.3 m,and 3.3 m,respectively.The accumulative deformation of the subgrade first rapidly

关 键 词：路基工程 动力特性 行车试验 激振试验 红黏土 浸水湿化 累积变形 

分 类 号：U416[交通运输工程—道路与铁道工程]