Trenchless Technology

Trenchless technology, also called no-dig, is a way of installing or replacing underground pipes and cables without digging a trench along the route. The tool travels between two small pits, one to launch it and one to receive it, and the surface in between is left alone. The main methods we supply are impact moling for new installations and pipe bursting for replacing pipes already in the ground.

The main trenchless technology methods are impact moling, pipe bursting, cable pulling and sliplining. With impact moling, a bore is hammered through the ground using compressed air, pulling a new pipe, duct or cable behind it. With pipe bursting, a rod is pushed through the old pipe and connected to a bladed head and the new pipe at the far end. The rig then pulls the rod back through, splitting the old pipe and drawing the new one in behind it as it goes. For cable pulling, we use a winch to draw a cable through an existing duct at a controlled speed and tension. For sliplining, we use the same winch to pull a new, smaller pipe through the old one and renew it.

The biggest advantage of trenchless technology is cost. Much of the expense of an open trench is not the pipework but everything around it: breaking out and reinstating the road, closing it while you do, and putting the landscape back afterwards. A trenchless method skips nearly all of that, so pipeline and cable work comes in cheaper as well as faster. It also means significantly less open excavation, although launch and reception pits still need appropriate support and access provisions, and it is kinder to the surroundings, which is why it is often chosen for work near trees, other buried services and heritage sites.

In displaceable soils such as sand, loam and gravel, moling is usually the simplest answer. Driven by compressed air, an impact mole hammers forward from a small launch pit and pushes the soil aside to form a bore, and the new pipe or duct follows it through. Our moles run from 45mm to 180mm diameter over lengths of up to 20m, which covers most road, driveway and rail crossings.

Where access is tight, the PB30 is usually the answer. It has just a 1 metre square footprint, runs off a powerpack or a mini digger, and breaks down into four pieces that fit in a van, so it works in yards, gardens and other spaces a full-size rig can't reach. It bursts pipes from 50mm to 60mm with a pulling force of 30 tonnes.

Trenchless methods can lay cables as well as pipes. An impact mole is often used to pull in power, phone and fibre optic cables or the ducting for them; used this way it is sometimes called a cable mole. A Grundowinch pulls cable through existing ducts, and because you control the line speed and tonnage, the cable is not stretched on the way in.

Sliplining renews an old pipeline by pulling a new, smaller pipe through it, usually with a constant-tension winch such as the Grundowinch. The trade-off is a smaller bore than the original. If you need to keep or increase the carrying capacity, pipe bursting is usually the better route, since the new pipe can match or exceed the old diameter.

Every rig we supply comes with safe use instructions, and we are happy to provide more detailed familiarisation training if needed – so your team can be confident with the equipment before work starts.

Hire is charged per week, and the price depends on the kit your job needs and how long it stays on site. Grundoburst rigs are delivered by trailer and supplied with 100m of rods, with extra rods available on request. Ask us for a quote and we'll price it up for you, often within 24 hours.