How does HDD work?
A basic overview of the fundamental aspects of Directional Drilling
This short video clip produced by Trenchless Solutions will give you an idea of the basic principles of how a HDD shot works - from the demonstration of the use of pressurised water to aid cutting and steering, the interaction between the walkover system and sonde in the pilot bore casing, to the attachment of a reaming tool to the product pipe via a swivel. As you can imagine, there is far more to it in reality - choosing the correct mud mix, the right pilot bore tooling, selecting the most suitable design and size of reaming tool dependant on ground conditions, pipe size and pre-ream runs is crucial for ensuring that the product pipe is pulled in effectively without damage to the road surface, the local environment or the product pipe itself.
HDD vs Open Cut
HDD comes out the clear winner - greater productivity, better for the environment and with less disruption to traffic flow and local communities - the full report is included below;
A unique direct comparison
This paper describes a field research study to capture and analyse site data comparing differences in environmental impacts, traffic impacts, and productivity between traditional open-cut construction and Horizontal Directional Drilling (HDD) portions of a replacement project of existing asbestos-cement waterline in Yuma, Arizona. The project was unique in that it provided a head-to-head comparison of the two methods in the same local environment.
How Do You Know Where the Drill Head is?
Location with the Digitrak F5 Falcon
We often get asked how the location system works; many assume it works like sonar, presumably because it is subterranean, like a submarine - in fact it is much closer to aeroplane technology, indeed, Digitrak DCI was founded by long-time friends, colleagues, aeronautical engineers, and avid pilots John Mercer and Peter Hambling in 1990. The relatively simple basics of the location system revolve around the transmitted signal field, this signal is detected by a rear locate point (RLP) and front locate point (FLP) - this gives you a locate line running effectively from the centre of the two points and in the true centre of the transmitter in the pilot head casing - The angle between the RLP and FLP poles is at a constant 70 degrees - this constant allows for any change in pitch, depth or topography to be observed in the change in the distance between the FLP and RLP which can be monitored by the F5 and HDD Operators, allowing for extremely precise adjustments and so accurate installation.
Open-cut causes 66.69% more environmental damage than HDD
Conclusion of an in depth analysis and study, included in full below