Influence of Construction of Deep Cutting Subgrade Adjacent to Upper Span on Existing Railway Tunnel Structure
Based on the project of a new railway deep cutting subgrade adjacent to upper span on the existing urban railway tunnel in proximity,MIDAS,finite element software,was used to build the three-dimensional numerical model of the tunnel site area.This model helped analyze the tunnel deformation and structural stress,and assessed the safety of the existing tunnel structure before and after the subgrade construction.The research shows that,the construction of the subgrade causes the secondary redistribution of the surrounding rock stress in the tunnel site area,which leads to the increase of the maximum tensile stress at the inverted arch by 0.567 MPa;the excavation unloading of the soil above leads to the overall uplift deformation of the structure,and the final deformation of the inverted arch is 4.169 mm.The rationality of the calculation results is verified by field monitoring.The load structure method shows that the safety factor of the existing structure below the subgrade will be reduced after the construction of the subgrade,but it is still within the safety specification limit.
deep cutting subgradeupper spanexisting tunnelfinite element calculationsafety factor
万方数据
维普
