Measuring the ground vibration caused by Suzhou Rail Transit Line 2 with acceleration sensor we study its propagation law.The 3 Dmodel of tunnel soil layer is established by finite element software.The ground vibration responses caused by rail traffic are simulated and compared with the measured data.The results show that:the horizontal vibration acceleration caused by rail transit in circular curve segment is 2 times than the vertical vibration acceleration within the range of 12 mfrom the center line of the tunnel.Outside the range

the two is same.Rail traffic has no significant effect on the horizontal vibration acceleration

but the impact of vertical vibration is farther.30

1

25Hz is the major frequency of horizontal vibration in circular

curve.40

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00Hz is the major frequency of vertical vibration.There is an enlarged area of vertical vibration in the range of 6

1

2m.Low frequency vibrations below 10 Hz in horizontal direction is enlarged within a distance range of 12

1

7m.Building around subway in this range requires special attention.