Study on the Mechanical Response Laws of Tunnel with the Station-First Then Interval Mining Method
To investigate the influence of interval tunnel excavation on the stress and deformation of a subway station's main structure,this study takes a subway station construction project in Urumqi as the background.A finite element model encom-passing both the station and the interval tunnels was established,and the reliability of the numerical simulation was validated by field monitoring data.The results indicate that,in the initial phase of station excavation,the top slab undergoes larger set-tlement,which gradually diminishes as excavation advances and support measures are implemented.During the interval tunnel excavation,different excavation sequences of the left and right lines lead to varying settlement behaviors,emphasizing the need for immediate support and real-time monitoring to prevent excessive unilateral settlement.Furthermore,the closer the tunnel excavation face is to the main station structure,the more pronounced its impact on the station.On-site measurements reveal that the contact pressure between the initial support and the secondary lining exceeds the surrounding rock pressure experienced by the initial support,and that the arch shoulder endures higher stress compared to other structural parts.These findings can provide useful references for controlling deformation and ensuring safety for similar tunnel construction projects.
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