摘要
为探究重载列车动载作用下路基的动力特性,依托浩吉(浩勒报吉吉安)重载铁路三荆(三门峡荆门)试验段水泥改良膨胀土路基工程背景,开展不少于400万振次(近似模拟运营10年内的荷载量)的现场激振试验,利用大型激振设备和配重块组合模拟了时速120 km、轴重2530 t重载列车作用,并与时速120200 km、轴重21 t预留客运列车作用时的激振试验结果对比。结果表明:动应力受轴重影响敏感性大于行车速度,轴重2530 t重载列车作用时路基面动应力幅值范围约是轴重21 t客运列车作用时的1.21.4倍;动应力与加速度沿路基深度衰减趋势吻合,在基床表层与底层范围最大衰减量分别可达40%和80%,动力影响深度略大于基床设计厚度;路基面累积变形呈“快速缓慢稳定”发展,控制在4 mm以内,其中前150万次占比达90%;结合测试结果评估水泥掺量为3%5%的改良膨胀土用作基床底层及以下路堤填料满足动力稳定需求。研究成果能够为探索重载铁路基床动力水平与结构设计提供理论参考。
In order to explore the dynamic features of subgrade under the dynamic load of heavy-duty train,based on the background of cement-stabilized expansive soil subgrade in San-Jing(Sanmenxia-Jingmen)test section of Hao-Ji(Hollerbaoji-Ji'an)heavy-haul railway,field vibration tests no less than 4 million vibration times are carried out.Using large-scale excitation equipment and counterweight combination,the effect of heavy-duty train with axle load of 25-30 t at 120 km/h is simulated and compared with the test results of reserved passenger train with axle load of 21 t at 120-200 km/h.The results show that the sensitivity of dynamic stress affected by axle load is greater than driving speed,and the amplitude range of dynamic stress on the subgrade surface under axle load of 25-30 t is about 1.2-1.4 times of that of 21 t passenger train;the dynamic stress and acceleration attenuation trend along the subgrade depth are consistent,and the maximum range attenuation can reach 40%and 80%respectively in the surface layer and bottom layer of subgrade bed,and the dynamic influence depth is slightly greater than the design of subgrade bed thickness;the cumulative deformation of the subgrade surface is"fast-slow-stable",which is controlled within 4 mm when it is stable,among which the first 1.5 million times account for 90%;combined with the test results,it is estimated that the dynamic stability of 3%-5%modified expansive soil used as the bottom layer of subgrade bed and the embankment below meets the requirements.The research results can provide the theoretical reference for the exploration of dynamic level and structural design of heavyhaul railway bed.
作者
商拥辉
徐林荣
SHANG Yong-hui;XU Lin-rong(Institute of Architecture and Engineering,Huanghuai University,Zhumadian 463000,China;School of Civil Engineering,Central South University,Changsha 410075,China;National Engineering Laboratory for High Speed Railway Construction,Central South University,Changsha 410075,China)
出处
《振动工程学报》
EI
CSCD
北大核心
2021年第6期1276-1283,共8页
Journal of Vibration Engineering
基金
国家自然科学基金资助项目(51778634)
河南省科技攻关项目(202102310264)
河南省教育厅项目(20B58003)。
关键词
水泥改良膨胀土路基
重载铁路
激振试验
动力特性
cement-stabilized expansive soil subgrade
heavy-haul railway
vibration test
dynamic features
作者简介
商拥辉(1985-),男,博士,讲师。E-mail:syhsrsci@sina.com;通讯作者:徐林荣(1964-),男,博士,教授,博士生导师。E-mail:xulinrong@zju.edu.cn。
