Analysis on the Seismic Response Reduction of Shock Absorption Layer in the Shallow and Unsymmetrical Pressure Section of Tunnel Portal in Strong Earthquake Area
Based on a railway tunnel portal section,this study utilizes FLAC3D to analyze the damping effect of different thicknesses of damping layers applied between the liner and the surrounding rock.The results show that:(1)Compared with no seismic damping layer,after applying a 5 cm damping layer,the maximum and minimum principal stresses of the secondary lining structure are reduced by 26.05%and 21.57%,the vertical and longitudinal displacements are reduced by 74.68%and 36.13%,the vertical displacement difference is reduced by 0.32 mm,and the minimum safety factor is increased by 50.46%on average.(2)After applying a 10 cm damping layer,the maximum principal stress of the secondary lining structure increases by 134.45%,the minimum principal stress decreases by 26.70%,the vertical and longitudinal displacements decrease by 70.80%and 26.89%,the vertical displacement difference increases by 1.85 mm,and the minimum safety factor increases by 11.10%on average.(3)After applying 15 cm damping layer,the maximum and minimum principal stresses of the secondary lining structure decrease by 45.38%and 25.16%respectively,vertical and longitudinal displacements were reduced by 70.89%and 13.45%respectively,vertical displacement difference increased by 1.89 mm,and minimum safety factor increases by 12.56%on average.(4)The seismic damping effect of applying 5 cm between the liner and the surrounding rock is better than that of 10 cm and 15 cm damping layers.The results can be used as a reference for the development of shock absorption technology in shallow tunnel portal.
维普
万方数据
