Abstract: A three-dimensional finite element model of tunnel-soil-superstructure was established by finite element software MIDAS GTS NX. The model was verified by comparing the model results with the measured vibration data. Based on the finite element model, the effects of vibration isolation layer, cushion sand layer and disc spring support on the vibration isolation of the metro superstructure were explored. The study took Guangzhou Metro Line 3 superstructure Boxue Building of South China University of Technology as the example, three kinds of vibration isolation methods were compared: (1)set up a 1.8m isolation layer on the basement roof and fill the rigid or flexible material in the vibration isolation layer, respectively;(2)set up a cushion sand layer at the basement floor and take the thickness of the cushion sand layer as variables; (3)design suitable disc springs through calculation, and optimize its layout, which are arranged in the bottom of the column and the slab, respectively. The direct integration method Newmark-β method of time history analysis was used for calculation. It finds that the disc spring has the best vibration isolation effect, and the average vibration isolation rate is 11.23%, which provides design suggestions for the vibration isolation measures of the metro superstructure.

Key words: metro vibration, frame structure, finite element, time history analysis, basic vibration isolation