This study aims at researching damage mechanism of tunnel portal and front slope caused by seismic excitation, while post-earthquake field investigations and shaking table tests were conducted. Seismic damage mechanism can be drawn from comparison between damage patterns of reality tunnel project
and tunnel model in shaking table tests. The results show that no matter tunnel structures are in static or dynamic state, the invert arch and side wall are the most vulnerable parts. Therefore, it is necessary to change transverse sections of transport tunnel and obtain exact value of curvature or replace material of side wall to enhance its aseismic capacity. Although it is security that tunnel constructed in solid and integrated surrounding rock, bedrock-overburden interface in the shallow tunnel sections is usually near the portals. Because of difference in the surrounding rock properties seismic damage is quite easily developed and inclined cracks are formed under the influence of Rayleigh surface waves. The more and better protective measures for top and weaken parts of front slope together with opening cut sections of tunnel should be researched and employed. The research results can provide reference for seismic fortification of tunnel structures.