铁路基床底层风积沙填料长期动力稳定性研究  

Study on long-term dynamic stability of aeolian sand filling at the bottom layer of railway subgrade bed

作　　者：马梦倩 聂如松[1,2] 钱冲 阮波[1] 祁延录 MA Mengqian;NIE Rusong;QIAN Chong;RUAN Bo;QI Yanlu(School of Civil Engineering,Central South University,Changsha 410075,China;MOE key Laboratory of Engineering Structures of Heavy Haul Railway,Central South University,Changsha 410075,China;Xinjiang Railway Survey and Design Institute Co.,Ltd.,Urumqi 830011,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学重载铁路工程结构教育部重点实验室,湖南长沙410075 [3]新疆铁道勘察设计院有限公司,新疆乌鲁木齐830011

出　　处：《铁道科学与工程学报》2024年第6期2284-2294,共11页Journal of Railway Science and Engineering

基　　金：中国铁路乌鲁木齐局集团有限公司科技研究开发计划课题(WLMQ-KGHZGS-HRTL-GGB-2020-0032);国家自然科学基金资助项目(51878666)

摘　　要：为了研究铁路基床底层风积沙填料的长期动力稳定性,以和若铁路某试验段路基为研究对象,开展现场动力响应试验,试验车速分别为5,20和30 km/h,轴重分别为14.5 t和23.5 t,分析动应力随列车速度、轴重及沿深度的变化规律,基于现场测试和以往动三轴试验成果,将临界动应力和累积塑性变形作为评价参数,分别从动强度和动变形2个方面评价和若铁路基床底层风积沙填料的长期动力稳定性。研究结果表明:1)当列车以不大于30 km/h的速度运行时,车速对基床动应力值的影响很小,但轴重的影响十分显著,不同轴重作用下动应力衰减系数沿深度的变化曲线基本重合,动应力经过基床表层衰减约39.7%,传递至基床底层底面衰减约84.6%。2)在和若铁路基床底层范围内,列车荷载产生的动应力为12.86~53.05 kPa,小于风积沙临界动应力66.02~100.21 kPa,从动强度角度来说,风积沙用作铁路基床底层填料满足长期动力稳定性要求。3)基于基床填料的累积塑性应变模型,采用分层总和法计算了和若铁路基床层的累积塑性变形,结果发现列车荷载作用下基床变形主要集中在第1个月,累积变形量为13.59 mm,小于规范允许的月沉降量25 mm,从动变形角度来说,风积沙用作铁路基床底层填料满足长期动力稳定性要求。研究成果可为沙漠地区路基填料选择及基床结构设计提供参考。In order to investigate the long-term dynamic stability of aeolian sand filling at the bottom layer of railway subgrade bed,the field dynamic response tests on a section of Heruo Railway were carried out.The test train speeds were set to 5,20,and 30 km/h,respectively,whereas the axle loads were 14.5 t and 23.5 t,respectively.The variations of dynamic stress with train speeds,axle loads,and depths were analyzed.Based on the results of field tests and dynamic triaxial tests,the critical dynamic stress and cumulative plastic deformation were chosen as evaluation parameters to assess the long-term dynamic stability of aeolian sand filling at the bottom layer of Heruo Railway subgrade bed from two aspects of dynamic strength and dynamic deformation.The key findings are as follows:1)when the train runs at a speed of no more than 30 km/h,the influence of train speed on the dynamic stress of the subgrade bed is very slight,but the influence of axle load is very significant.The variation curves of dynamic stress attenuation coefficient along the depth basically coincide under different axle loads.The dynamic stress attenuates about 39.7%through the surface layer of the subgrade bed and about 84.6%through the bottom layer of the subgrade bed.2)Within the range of the bottom layer of the Heruo Railway subgrade bed,the dynamic stress caused by train load is about 12.86~53.05 kPa,which is less than the critical dynamic stress of aeolian sand of 66.02~100.21 kPa.From the perspective of dynamic strength,the aeolian sand used as the filling at the bottom layer of railway subgrade bed satisfies the long-term dynamic stability requirements.3)Based on the cumulative plastic strain model of subgrade bed filling,the cumulative plastic deformation of the Heruo Railway subgrade bed was calculated by the splitting summation method.The calculation results show that the deformation of the subgrade bed under the train load is mainly concentrated in the first month.The cumulative deformation in the first month is 13.59 mm,which is less than

关 键 词：风积沙 基床底层 长期动力稳定性 临界动应力 累积塑性变形 

分 类 号：U213.1[交通运输工程—道路与铁道工程]