Abstract：Firstly，a brief information of domestic and abroad undersea tunnels as well as their designing，construction and special features of research work is presented. The comprehensive exploration techniques of engineering and hydrogeology of the seabed rock and the determination factors on minimum buried depth of the undersea tunnels are discussed. The problems are analyzed and addressed，which include exploration and treatment of the ground-water under tunneling，prediction and warning alarm against the collapse danger of the surrounding rock of undersea tunnels，and its stability evaluation，adjustment and correction on preliminary design parameters of tunnel lining during construction etc.. Secondly，some opinions on the technical problems of material selection for undersea tunnel lining(marine engineering concrete) with high quality and durable anti-corrosive property，disaster prevention and emergency aid for long and large undersea tunnels in highway and city expressway are presented. Some key issues related with excavation by a super-large shield machine and the design and construction of immersed tunnel in deep seawater and torrent conditions are also listed. Issues mentioned above may have a consulting value to design and construction of several undersea tunnels which are just under or awaiting for construction in China.
