UNDERGROUND DUCT LINE

摘要

PROBLEM TO BE SOLVED: To facilitate the leveling of the bottom of an excavated ditch with good workability and easily ensure the linearity of a duct. SOLUTION: In this duct line, a number of duct bases 2 of a required length having a plurality of grooves 4 for housing the half circumference of a duct formed in parallel on the upper surface are arranged with the end surfaces being butted so as to continue the grooves 4. Short duct pillows 3 having a plurality of recessed parts 5 for housing the half circumference of the duct formed in parallel on both upper and lower surfaces are arranged at prescribed intervals in the longitudinal direction of the ducts 1, and lengthy ducts 1 are laid with the upper surface-side recessed parts 5 of the duct pillows 3 as guides. This is repeated once or more to lay pipes in a plurality of stages.