What it involves

Directional Drilling involves the installation of a new pipe by drilling a ‘mini-tunnel’ and pulling or pushing the pipe into it. A ‘steerable’ trenchless method of installing new underground pipes. A pilot bore is drilled from a launch pit at one end of a route, to an exit pit at the other end. The drill head contains a transmitter enabling the operator to know the position, depth, pitch and roll of the drill head. This enables continuous adjustments to the line and level to be made throughout the drilling process. When the pilot bore is complete, the drill head is replaced with another hole opening device (reamer), which is rotated back through the bore increasing the diameter. When the target diameter is reached, the reamer is replaced by a swivel and towing head, the pipe is attached and pulled through the bore to complete the installation.

Our Service

  • A Survey of the proposed route and examination of all known utilities in the area is critical for success.
  • Launch pits and reception pits should be established at each end of the bore.
  • The drill head transmitter should be tested for functionality and accuracy before launch.
  • Drill the pilot, checking the line and level at all times.
  • Check levels in launch and reception pits.
  • Enlarge the hole using a reamer, and maintain the integrity by injecting drilling mud.
  • Check and confirm invert levels in launch and reception pits.
  • Install the pipe.
  • Make good the launch and reception pits if created.

Our Process

  • A Survey of the proposed route and examination of all known utilities in the area is critical for success.
  • Launch pits and reception pits should be established at each end of the bore – can be surface launched and received, however typically this requires a connection up and down stream so pits are often sensibly used.
  • The drill head transmitter should be tested for functionality and accuracy before launch
  • Drill the pilot, checking the line and level at all times
  • Check levels in launch and reception pits
  • Enlarge the hole, typically using a reamer, and maintain the hole integrity by injecting drilling mud
  • Check and confirm invert levels in launch and reception pits
  • Install the pipe
  • Make good the launch and reception pits if created.

Requirements

  • Pipes from 50mm to 1200mm diameter.
  • Known ground conditions.
  • Locate all buried structures and utilities in the area.
  • Identify extent and depth of foundations of all structures in area.

When to use Directional Drilling?

  • Some pipes, sewers or drains have problems with their gradient such as dips or bellies. Pipe bursting or lining would only clone these problems in the rehabilitated pipe
  • In this scenario and for other reasons, it can be appropriate and cost-effective to use Directional Drilling to create another pipe beside the existing one, without having to resort to trenching and all the associated disruption.

How we can help

Directional Drilling is an activity where experience is key due to the varied nature of the ground and site set-ups. The McAllister Group possesses the necessary experience in house to use this application; the company can also gain from the knowledge of a number of specialist partners who have a broad range of equipment and knowledge. We recommend Directional Drilling when lining and other solutions are inappropriate. We will either install the new run ourselves or, on occasion, oversee one of our partners completing the job.