Effect of Rubber Soil Backfill on Vibration Isolation of Open-cut Tunnels

［Objective］During the operation of urban rail transit, the train operation induced vibration can damage buildings and precision instruments along the line, and even affect people's daily lives. Therefore, effective vibration reduction measures need to be studied. ［Method］The long-mileage open-cut section tunnel of Xiong'an Rail Transit R1 Line is taken as an example, which uses rubber soil instead of plain fill. With numerical simulation method, a corresponding tunnel-stratum finite element model is established in ABAQUS software to analyze the vibration isolation effect of different rubber soil damping ratios on open-cut tunnels. ［Result & Conclusion］Using rubber soil with a damping ratio of 0.04 for backfilling can reduce the ground vertical vibration acceleration by 6.2% and the vibration acceleration level by 1.1% at most; using rubber soil with a damping ratio of 0.06 for backfilling can reduce the ground vibration acceleration by 11.4% and the vibration acceleration level by 1.3% at most. The vib-ration isolation effect of rubber soil with the above two damping ratios on open-cut tunnels is quite obvious. At the same measuring point, the reduction amount of vibration acceleration and vibration acceleration level by rubber soil with a damping ratio of 0.06 is generally greater than that by rubber soil with a damping ratio of 0.04, with the maximum reduction rates reaching 5.2% and 0.667% respectively.