UNDERGROUND PIPE LAYING METHOD BY INSIDE AND OUTSIDE METHOD

PURPOSE:To eliminate non-working time between a civil engineering team and a welding team and to improve economy by execution of regular welding of joints which are restrained by the outside welding alone from the inside by the welding team by making use of the time zone which does not interfere the working time of the civil engineering team. CONSTITUTION:In a method for underground piping which involves installation of steel pipes under the ground, pipes are restrained by thin wall welding from the outside surfaces of the pipes in the excavated ditch of the position where the joints of the pipe installed in the previous work and the pipe to be installed in the next work are coupled (the width for conventional inlets is not required). Immediately, lining plates are put on the enclosure wall of the inlet of the position where the joints are coupled, and the ditches other than the same are backfilled. In the time zone which does not interfere with the above-mentioned work, the regular welding is executed by inside welding from the other end side of the pipes through remote operation by the welding team by the use of an automatic inside welding machine. In succession to said welding, inspection, corrosion preventive treatments and other jobs are carried out.