Pipe bursting is an eco-friendly trenchless pipe laying method which replaces existing host pipes by displacing their fragments into surrounding soil while simultaneously pulling in the new product pipe of the same or larger diameter into the void created. Pipe bursting can be applied from pit to pit, pit to manhole and manhole to manhole.
Pipe bursting has a long tradition, but would never have been so successful or even imaginable without piercing tool/impact moling technology and horizontal steel pipe ramming. The first idea to replace pipes by bursting was elaborated by British Gas and UK’s DJ Ryan engineering company.
Pipe Bursting Methods
PNEUMATIC PIPE BURSTING
Pneumatic bursting is assisted by a portable winch. A pneumatic cracking hammer based on a piercing tool or horizontal ramming hammer is used to break and displace the host pipe. The pipe bursting tools are arranged at the front or rear end of the bursting hammer and transmit the ramming energy into the host pipe and crack it. The following expander displaces the burst fragments of the host pipe into the surrounding soil and enlarges the void so that a new pipe of the same or larger diameter can be pulled in, simultaneously.
Initially a winch wire is pulled into the host pipe using a fibre glass rod. The new pipes are joined outside the pit, normally a butt-fused polyethylene pipe string. The new pipe is attached to the cracking hammer and the hammer itself is connected to the air compressor and pulled into the host pipe by the winch.
The pipe bursting process commences by starting the compressor. The pulling force of the winch assists the forward movement and directional stability of the cracking hammer. When the cracking hammer arrives in the exit pit it can either be removed or pulled back through the new pipe into the launch pit if space is restricted.
STATIC/HYDRAULIC PIPE BURSTING
The hydraulically driven pipe bursting rig is positioned inside the exit pit. A flexible guide rod ensures smooth installation of the bursting rods through the host pipe. The rods are connected and quickly added one at a time as they are pushed up the old host pipe. Once at the launch pit the guide rod is replaced by a bursting tool (e.g. bladed bursting head, roller blade cutter) expander and new pipe.
The entire configuration is then pulled back by the hydraulic pipe bursting rig through the host pipe towards the exit pit.