Abstract: This paper presents the hydrogeological survey results of a proposed crosssea tunnel in Qingdao. After a brief introduction of the hydrological features such as, site geological conditions, groundwater characterization and distributions, the groundwater inflow quantity of land portion as well cross-sea portion during the tunnel construction are estimated, respectively. The results indicate that, the estimated groundwater inflow in land portion is less than 3.67 m3/(d·m） and this quantity has negligible adverse impact on the tunnel construction. However, the groundwater inflow quantity in crosssea portion is approximately between 0.92 and 19.73 m3/(d·m）. This inflow quantity belongs to the property of medium permeable soil stratum.

Key words: Cross-sea Tunnel, Hydrogeological Characteristics, Groundwater Inflow Prediction, GroundwaterInflow Model