WELDING METHOD OF RECTILINEAR/CURVED LINE CONNECTIVE PORTIONS TO LARGE STEEL PIPE OF MORE THAN PHI 700 IN TUNNEL

摘要

PURPOSE: A welding method of rectilinear/curved line connective portions is provided to improve tunnel excavation efficiency and to save costs by minimizing a diameter difference of a tunnel for installing a steel pipe. CONSTITUTION: A tunnel is secured for a welding work outside at a point needing steel pipe connection. The outside and inside of portions where outside welding is possible are all welded at an input port. For an area where the outside welding is impossible, the number and extension of expansive portions(3) are minimized by welding the outside and inside of a rectilinear or curved pipe at the expansive portion. In inputting the steel pipe, a manhole(6) is installed after installing a ventilation equipment. The outside welding is performed after installing the ventilation equipment or an oxygen respiration device. Then, the manhole is closed and a spaced between the steel pipe and tunnel is filled up.