Report on the construction of the triple circular-face shield tunneling at Iidabashi Station (provisional name) on Metropolitan Subway Route 12

摘要

In comparison with the circular face shield tunneling, the triple circular-face shield cannot expect an sufficient arching effect at the face. To compensate this drawback, we previously evaluated potential adverse effects of the ground alteration on the surrounding structures by means of the finite element method-based analysis of the ground alterations, and took protective measures for them, along with the management of measurements on the works. We adopted an unprecedneted integrated-girder linign structure for the platform works, featuring integration of a girder structure into the segments.