In connection with Lan-Yu railway Liangshui Tunnel’s characteristics of soft rock and large span

a kind of new type support structure including thickening shotcrete and secondary liner and double deck is adopted. A laboratory triaxial creep test to on-site specimens is carried out to study the creep properties of the carbonaceous phyllite. According to the test results

Burgers creep model is adopted to describe the long-term rheological behaviour of carbonaceous phyllite. Combined with on-site practical support ways; the fast Lagrangian analysis of continua in 3 dimension (FLAC3D) is used to simulate surrounding rock’s rheological mechanical behaviour in DK357+976 after the completion of this tunnel. Surrounding rock’s deformation and supporting structure’s mechanical behaviour during operation are analyzed. The research results show that secondary liner can effectively reduce surrounding rock’s creep deformation; and only part of vault shotcrete will yield 100a later. The on-site new support ways can ensure long-term stability of the tunnel.