Replacing pipeline and replacement pipe construction

摘要

An existing pipeline is replaced by causing a pipe-bursting head to be moved through it so as to split it into pieces, a new pipeline being towed behind the bursting head; the new pipeline is formed from a length or lengths of pipe having a polyethylene main pipe body and an outer protective layer of polypropylene which has enhanced abrasion resistance, cut resistance and point impingement resistance relative to the polyethylene, and wherein the polypropylene layer is readily removable in at least the end regions of the pipe to enable the end regions to be coupled to other pipelines or pipe elements by mechanical and/or fusion means. The outer layer is not bonded, but, at the most, lightly adhered to the main pipe to enable the outer layer to be cut away at the pipe section ends to enable jointing of sections. Optionally, the outer layer incorporates toughening agents, e.g. mineral based, glass beads, hollow glass spheres.