Fragmentation is a trenchless technique used to replace existing pipelines in place without having to physically remove the pipe. During the fragmentation process, the existing pipe is demolished to allow for the installation of new pipe. This process involves mechanically pulling a conically shaped tool (bursting head) through the existing pipe, causing it to shatter.
The bursting head displaces the fragments into the surrounding soil, creating a clear cavity for the new pipe installation.
Trenchlesspedia Explains Fragmentation
Fragmentation was initially developed in the 1980s to demolish and replace small cast iron distribution lines. Since then, it has grown to be an accepted and effective method for replacing water, sewer and gas pipelines constructed from brittle materials such as concrete, cast iron and clay.
The back end of the bursting head, which is typically larger in diameter than the existing pipe, is connected to the new pipe and the front end is connected to a cable or steel pulling rod. The new pipe and bursting head are pulled from the insertion shaft by a pneumatic or hydraulic power source located at the pulling shaft. The bursting head simultaneously shatters the existing pipe while pulling and installing the new pipe behind it.
This trenchless technique avoids the need to acquire additional right-of-way due to extensive and costly excavation.