Abstract
A vertical shaft of shield tunnel plays a role of bearing pile-wall to resist earth pressure at excavation, but the part of the shaft must be cut to proceed a shield tunnel horizontally. Therefore, the requested properties for the shaft are sufficient resistance against bending moment and easiness for cutting by shear force. For this purpose the authors have developed a hybrid member consisting of a fiber reinforced foamed urethane (FFU) member and a steel pile member. The key of the hybrid member lies in how to connect both members. Two connection methods, such as a cotter connection and a bond connection are proposed and the mechanical behaviors of them are examined experimentally in terms of flexure and shear. Finally, the prototype is tested and is proved to have sufficient strength for actual use.
