Ground movement: issues for pipeline installations

Ground conditions can vary when being worked on during pipeline installations. Moling is a technique used by most contractors when replacing pipes, weather this be water, gas, or sewage. However, this technique can cause problems when excavating in difficult ground conditions.

These ground conditions can vary, soft ground conditions may cause the mole itself to sink as it works through the ground to replace the decommissioned or broken pipes. The ground being so soft cannot provide enough resistance for the action of the moling to be successful. Furthermore, rough, hard rocky ground can cause bumping into rocks therefore changing the direction of the mole and making the excavation unsuccessful.

In urban environments there maybe various multiple buildings in close proximity to the construction space making any excavation extremely difficult as it’s a higher risk that the ground may move because of the pressure. The deeper the excavation means that the risk goes up, as when out of balance the ground pressure can move both the ground below and infrastructure above.

A solution to the unpredictable ground surface when replacing pipelines is the trenchless technology of pipe pulling methods. This technique uses existing pathways so eliminates any risk that excavation causes, and simply pulls the old pipe out and threads the new pipe in, in one fluid movement. This solution is cost effective and minimises the risk that uncertain surfaces cause.

Kobus supplies a specially designed pulling cable which comes complete with integral ferrule and expander. The ferrule allows attachment to the new pipe so it can be towed in behind the old pipe.  The expander opens up the bore hole behind the old pipe. The cable is ready to use without the need for any fiddly assembly on site.

The Kobus Puller is designed with a small footprint. The tapered design on the foot section allows better clearance from surrounding utilities. The Puller is positioned easily in small excavations, even with very congested utilities, and doesn’t require a large clear flat area at the base of the excavation.

The Kobus Pipe Puller extracts the old pipe continuously providing smooth extraction of the pipe without stopping and starting. This ensures the pulling is quick without the need for manual operation of any device.  There’s no need to cut the tough old metal pipe with shears that may need regular replacement.