OPEN SHIELD CONSTRUCTION METHOD AND CONCRETE CAISSON USED THEREFOR

摘要

PURPOSE:To increase rigidity so as to prevent the occurrence of defect and cracks in the outer peripheral corner portion and to improve water cut-off capability by covering the outer peripheral corner portions of the front and rear end surfaces of a concrete caisson and their vicinity with steel plates having an L-shaped section to protect the portions. CONSTITUTION:Steel plates 14 having an L-shaped section are installed on the outer peripheral corner portions of the front end portion and the rear end portion of a concrete caisson 4 and their vicinity in such a manner as to wrap the portions from the outside, and the concrete caisson 4 is hung down to be installed. The concrete caissons 4 are joined to each other in such a manner that the vertical plates 14a of the steel plates 14 are pressed to each other and the outer peripheral corner portions are joined by welding 15 the outer periphery. Thus, the concrete caissons 4 are duplicately watertight sealed, internally and externally so as to improve the sealing performance, and the occurrence of breakage and cracks in the corner portions can be prevented.