板式轨道交通引起的地面振动模型

为了研究板式轨道交通引起的地面振动,建立了单个载荷作用下板式轨道引起的地面振动计算模型。在模型中,考虑了板式轨道的结构特性,大地按多层各向同性无限大弹性体建模,其底层为弹性半空间体。对模型的动力学微分方程先在波数-频率域内进行求解,然后利用傅立叶逆变换得到地面振动的垂向位移幅值计算表达式。算例表明,该模型能反映出层状大地中波的频散特性,荷载移动速度对地面振动有显著影响,荷载速度增大,振动响应及影响范围随之增大,当其超过瑞利波波速时,将会出现多普勒效应,这说明该模型能模拟地质沉积作用下的层状大地特性。

Model of ground vibration generated by slab track

A model was established for the study of ground vibrations generated by slab track that was subject to a unit force,the characteristics of slab track were considered,ground was modeled as a number of infinite-parallel-homogeneous-elastic layers overlying elastic half-space,the dynamic differential equations of the system were solved in wave-number domain,and then the vertical displacement amplitude of ground surface was obtained by implementing inverse Fourier transform.The applied result of the model shows that the dispersion characteristics of the vibrations propagating in ground can be demonstrated,the load speed has significant influence on ground vibrations,the spread scope and response amplitude of vibrations increase with load speed increase,Doppler effects occur when the speed is greater than Rayleigh wave speed,which indicates that the model can simulate the alluvial depositing stratification characteristics of ground.2 tabs,6 figs,12 refs.