Is used in open shield tunneling method the concrete box

摘要

PROBLEM TO BE SOLVED: To provide a concrete box body used in an open shield method capable of improving adhesion between the concrete box body and a grout filling the neighborhood thereof, obtaining reaction force not only from the concrete box body but also from frictional resistance with the neighboring bedrock when an open shield machine is propelled to reduce the influence of propellant on the concrete box body and preventing the floating or the settlement of the concrete box body. SOLUTION: The concrete box body used in the open shield method is so constituted that the shield machine is driven forward by using the concrete box body in the rear as reaction force and that a void between the concrete box body and the bedrock is filled with the grout to successively bury a plurality of concrete box bodies in a vertical row, and recessed sections 12 are formed in both outsides of the concrete box body 4 as cotters.