Influence of plasticity and vibration isolators on an underground floating slab track using finite element analysis

The floating slab track (FST) is largely viewed as the most efficient structure for mitigating the vibrations caused by underground railway systems. This paper presents a study on the dynamic behavior of the FST subjected to train-induced vibrations using a finite element approach. A three-dimensional simulation model of an FST was analyzed under a moving load. The effects of material plasticity of underground strata and concrete damaged plasticity of the floating slab were analyzed. A comparison between the vibration attenuation of the steel-spring isolator (SSI) and polyurethane pad (PUP) was performed. The load was moved at constant speeds ranging from 90 to 324 km/h using a pressure-loaded moving block. The results were analyzed in the form of four general output parameters. A slight vibration attenuation was observed when plastic material properties were included in the simulation model. The PUP was more effective in reducing vibrations at FST than SSI by a vibration transfer mechanism.