Abstract: Anti-crack prestressed lining is mostly used in shallow-buried pressurized tunnels in China. However it is costly when widely used in long-distance water diversion tunnels. In view of this, we simulated the exosmosis of shallow-buried pressurized tunnel by using finite element method according to the coupling of seepage field and stress field of fractured rockmass. In the simulation we considered the impact of consolidated grouting, underground water level, and seepage field variation on the rockmass to reflect the changes of surrounding rock stress during the tunnel excavation, water filling and pressurization. We obtained that the increase and decrease of pore water pressure both could reduce the effective stress of rockmass. Thicker surrounding rock will bring about larger bearing capacity. Whether anti-crack design should be adopted in shallow-buried long-distance pressurized diversion tunnel is dependent on multiple factors. These factors include the frequency of high pressure water, leakage amount, consolidation grouting to improve the impermeability of surrounding rock, seepage pressure of rockmass, effective stress and rock mass structure, as well as drainage channel structure and control of rockmass leakage instability.

Key words: long distance water diversion, water diversion project in central Jilin Province from Songhua River, shallow buried pressurized tunnel, seepage-stress coupling, anti-crack design, numerical simulation