有砟与板式无砟轨道结构对高速铁路地基振动的影响分析

Influences of ballasted track and slab ballastless track structures on ground vibration of high speed railway

将既有的车辆-有砟轨道-路基-层状地基耦合系统垂向振动解析模型进行修改,使模型适应于板式无砟轨道的状况。针对我国客运专线线路情况,利用模型比较分析了有砟与板式无砟两种轨道结构下高速列车运行引起的地基振动,得到地基表面垂向振动加速度的振级、时程曲线和Z振级,动应力的功率谱与时程曲线;并讨论了轨道随机不平顺对地基振动的影响。分析结果表明：板式无砟轨道具有更好的隔振能力,板式无砟轨道情况下的地基振动加速度和动应力都明显小于有砟轨道的情况,其中Z振级减小约10~20 d B,且减小振动的主要频率分布在10~40 Hz的中频范围内;移动轴荷载对地基的低频振动贡献较大,而轨道随机不平顺主要对中高频振动产生作用,且板式无砟轨道情况下轨道随机不平顺对地基振动的影响远大于有砟轨道的情况,因此板式无砟轨道需更严格控制轨道的平顺状态。

An existing analytical model for analysing the vertical vibration of a vehicle- track-subgrade-layered ground coupling system with ballasted track was modified to a new model that adapts to the coupling system with slab ballastless track. Focusing on the passenger dedicated railway lines in our country,ground vibrations generated by high speed train running on the railway line with ballasted track and slab ballastless track structure were analyzed and compared. The vibration levels,time histories and Z vibration levels of the vertical ground accelerations and the power spectrums and time histories of the dynamic stresses on ground surface were gained,and the influences of track random irregularities on ground vibration were also discussed. The analysis results show that the vibration isolation capability of the slab ballastless track is better. The vibration accelerations and dynamic stresses of the ground with slab ballastless track are less than those with ballasted track. The Z vibration levels decrease about 10 ~ 20 d B,moreover,the reduced vibration components mainly distribute in the frequency range of 10 ~ 40 Hz. The moving axle load is of great contribution to the ground vibration in low frequency range,nevertheless the track random irregularities mainly affect the ground vibration in medium and high frequency ranges. The track random irregularities of the slab ballastless track have greater influences on ground vibration than those of the ballasted track. So,the track irregularities of the slab ballastless track should be strictly controlled.