Influence of Soft Soil Seismic Subsidence on Underwater Shield Tunnel under High-speed Train Vibration
Based on the Zhanjiang Bay undersea tunnel project of Guangzhou-Zhanjiang high-speed railway,a numerical model of"strata-tunnel-track bed"was established to study the influence of soft soil seismic subsidence on shield tunnel structure under high-speed train vibration from different thicknesses and relative position of soft soil layer.The results show that the settlement of the shield tunnel increases with the increase of the thickness of the soft soil,while the acceleration response has little to do with the thickness of the soft soil.The velocity response does not change much at the beginning(when the thickness of the soft soil is 11.0-20.0 m),and then decreases(when the thickness of the soft soil is 20.0-21.5 m),and finally increases rapidly(the thickness of the soft soil is more than 21.5 m).The dynamic response of a shield tunnel is greatly affected by the position of the soft soil layer.When the tunnel does not pass through the soft soil layer,the settlement and velocity values are small;when the tunnel partially passes through the soft soil layer,the settlement and velocity values follow the section through the soft soil.When the full section of the tunnel passes through the soft soil layer,the settlement and velocity values increase rapidly.