Abstract: Rare researches were focused on the simplified method of aseismic calculation for highway tunnels. A quasi-static calculation of the seismic response of highway tunnel is proposed. In this method, the tunnel lining structure is regarded as frame structure on elastic foundation, and the horizontal seismic force on the structure is simplified as equivalent horizontal concentrated force on element nodes of the structure. The lateral elastic resistance is assumed to be distributed in an inverted triangle, which is zero at the bottom of the wall and reaches the maximum at the vault. The value of lateral elastic resistance should be in balance with horizontal equivalent seismic force. A double-lane highway tunnel with rock of grade Ⅳ is taken as a case study. Through comparison and selection, the value of correction coefficient  η  of the horizontal seismic action is determined. Hence, through static structural analysis, the equivalent bending moment diagram is obtained, which is similar to the distribution graph of dynamic analysis, with the maximum values close to each other. The corresponding maximum axial force and maximum shear force can be obtained through respectively multiplying the adjustment coefficient of axial force and shear force by the internal force resulted from the static structural analysis. The method could be taken as a reference for engineering design and further research.

Key words: highway tunnel, seismic response, aseismic design, quasi-static method