A　time-dependent　unified　displacement　function　is　proposed　to　capture　main　deformation　responses　of　the　tunnel　cross-section.　When　the　expansion　order　n　equals　2,　this　complete　displacement　mode　is　used　as　displacement　boundary　condition　(DBC)　of　the　tunnel　cross-section.　Complex　variable　method　is　adopted　in　order　to　obtain　an　elastic　analytical　solution.　Considering　the　time　effect　of　ground　mechanical　parameters　and　tunnel　cross-section　deformation,　a　viscoelastic　analytical　solution　of　ground　displacement　is　obtained.　By　parametric　analyses,　time　effects　of　settlement　trough　curve,　ground　displacement　and　the　settlement　at　the　center　point　of　ground　surface　are　analyzed.　©　2020　8th　Japan-China　Geotechnical　Symposium:　Challenges　to　Breakthrough　in　Geotechnic.　All　rights　reserved.