Trenchless Technology & Subsurface Construction

Chapter 6

Trenchless Replacement

A pipeline with in adequate capacity or whose structural condition is too poor for relining can often be replaced without excavation using an 'in-situ' or 'on-line' pipe replacement system.

The most commonly used method of on-line replacement is pipebursting, in which a percussive tool (usually a modified impact mole) or a hydraulic expander breaks out the existing pipe, and a new pipe is pulled or jacked in behind. Pipebursting is referred to in certain countries as 'pipe cracking'. Some systems do not use a mole, but rely entirely on axial jacking or pulling force acting on a tapered bursting head.

Pipebursting technology was developed in the early 1980s, originally for the replacement of old cast iron gas mains. Following widespread use also in the UK water industry for the replacement of small diameter cast iron potable water systems, pipebursting now has an increasing market worldwide.....................for more details