METHOD AND STRUCTURE FOR LAYING COMMUNICATION CABLE IN UNDERGROUND LINE, AND MEMBERS USED FOR LAYING

摘要

A method of laying a communication cable (16) capable of laying an optical fiber cable (20) in an underground line such as a sewage line without applying a direct tension to the cable and without loosening the cable, capable of laying the optical fiber cables (20) on the upper side of the line for a main line allowing a plurality of optical fiber cables (20) to be laid therein, and eliminating the need for an expensive robot in the laying operation, comprising the steps of disposing highly strong and low extendable tension members (25, 26, 27) slidably in longitudinal direction of the optical fiber cables (20, 21, 22), pulling the tension members (25, 26, 27) into the underground line (1) by pulling, and applying a tension to a trunk tension member (25) between manholes (2) and (3) to stretch the trunk tension member (25) generally linearly in the underground line (1) so as to lay the optical fibers (20, 21, 22) on the upper side of the underground line (1), wherein a tension is applied to the branch tension members (26, 27) in branch pipes (4, 5) so as to prevent the branch optical fiber cables (21, 22) from being loosened in the branch pipes.