中文摘要：

以某重载铁路隧道工程为依托,结合现场实车试验和数值模拟,研究30t轴重列车荷载作用下重载铁路隧道基底结构的应力分布和动力响应,并针对目前由仰拱不同施工水平形成的3种主要基底结构形态进行对比分析。结果表明：数值模拟得到的隧道基底结构动力响应结果和现场实测结果吻合较好;重车线侧的隧道基底结构动应力明显大于空车线侧;垂向动应力沿隧道基底竖向的衰减较明显,至填充层底部时衰减率为74.3%,至仰拱底部时衰减率高达83.6%;水平向动应力在道床位置为压应力,在仰拱位置为拉应力,在填充层中由上至下应力出现由压到拉的转换;仰拱等基底结构的施作效果对基底结构的静、动力特性均有较大影响,严格按照设计进行施工的仰拱（曲线型断面）受力情况最好,最大拉应力仅为4.6kPa,且传至仰拱底部的动压力最小,为26.6kPa;仰拱施工成铺底结构时（直线型断面）其受力情况最不利,在仰拱与边墙连接处及仰拱中心位置出现较大拉应力,最大值为86.6kPa,且传至铺底结构底部的动压力最大,为47.3kPa;折线型断面的基底结构受力情况居中。

英文摘要：

Based on a heavy haul railway tunnel project,the stress distribution and dynamic response of tunnel base structure under 30 taxle load was studied by field real vehicle test and numerical simulation.Three main base structural morphologies due to different levels of invert construction were chosen to carry out comparative analysis.Results show that the dynamic response of tunnel base structure obtained from numerical simulation agrees well with that obtained from field test.The dynamic stress of tunnel base structure on loaded car line is significantly higher than that on empty car line.The vertical dynamic stress attenuates significantly along the vertical direction inside tunnel base structure.The attenuation rate is74.3% on the bottom of filling layer and is up to 83.6% on the bottom of inverted arch.The horizontal dynamic stress is compressive stress in ballast bed,tensile stress in inverted arch,and shifts from compressive to tensile stress from the top to the bottom of filling layer.The static and dynamic characteristics of tunnel base structure are greatly affected by the construction quality of inverted arch and other base structures.The stress status of inverted arch（curve section）which is constructed in strict accordance with design is the best,the maximum tensile stress is only 4.6kPa,and the dynamic pressure transmitted to the bottom of inverted arch is the smallest,which is 26.6kPa.The stress status of the inverted arch which is constructed as bedding structure（straight line section）is the worst.Greater tensile stress occurs at the joint of inverted arch and side wall as well as the center of inverted arch.The maximum tensile stress is86.6kPa,and the dynamic pressure transmitted to the bottom of bedding structure is the greatest,which is 47.3kPa.The stress status of the base structure with the section of polygonal line is medium.