Abstract:Norway has the largest number of subsea tunnels in the world. During the last 30 years,more than 40 subsea tunnels have been constructed,totaling more than 240 km. Though most of these tunnels are located in fair to good ground conditions,some challenging ground conditions have been encountered in connection with faults. A main feature during planning and construction of the Norwegian subsea tunnels is sealing the potential inflowing water. A systematic method for detecting such water in time and to seal it has been developed and refined over the years,and has been used in all Norwegian subsea tunnels. This is presented together with few of the more problematic construction experiences to prevent a cave-in to further develop and that involving ground freezing. Further,the application and implementation of the Norwegian experiences are discussed in the planning and during construction of the Xiamen Xiang¢an subsea tunnel,located in partly problematic and challenging ground conditions. The application of the Norwegian experiences is assisted through the consulting services provided by Norconsult experts during the tendering and the ongoing construction of the Xiang¢an subsea tunnel.