铁道科学与工程学报2024，Vol.21Issue(6)：2284-2294,11.DOI:10.19713/j.cnki.43-1423/u.T20231466
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
摘要
Abstract
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 the monthly settlement of 25 mm allowed by the design code.From the perspective of dynamic deformation,the aeolian sand used as the filling at the bottom layer of railway subgrade bed satisfies the long-term dynamic stability requirements.The research results can provide reference for the selection of subgrade filling and the design of subgrade bed structure in desert areas.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Key words
aeolian sand/bottom layer of subgrade bed/long-term dynamic stability/critical dynamic stress/cumulative plastic deformation分类
交通工程引用本文复制引用
马梦倩,聂如松,钱冲,阮波,祁延录..铁路基床底层风积沙填料长期动力稳定性研究[J].铁道科学与工程学报,2024,21(6):2284-2294,11.基金项目
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) （WLMQ-KGHZGS-HRTL-GGB-2020-0032）
国家自然科学基金资助项目(51878666) （51878666）
