Directional boring or horizontal directional drilling (HDD) is a trenchless technology employed to install underground pipes without affecting the area above the borehole.
Directional boring is used for the installation of utility pipelines and conduits. Most underground boring contractors use HDD for crossings constructed along roads, existing structures, and rivers. It takes the utility from one point to another without disturbing the existing ground or obstacles between the points.
This article explains the features, construction steps, and benefits of directional boring in the construction industry.
Directional Boring Process
The directional boring method is a three step process.
- First, a pilot hole is drilled from one surface point to the other. The drilling takes place along the directional path.
- After drilling, the bore is enlarged to a diameter that would allow the installation of the required pipe.
- Finally, the pipeline is pulled into the hole. The process creates a continuous segment of pipes underground.
Image Courtesy: Pinnacle Construction
Features of Directional Boring
- Directional boring is employed when the trenching or traditional excavation process is not practical.
- It can be employed for a variety of soil conditions.
- The types of pipes that can be installed using directional boring are- PVC, ductile iron, polyethylene, steel, and polypropylene.
- HDD is not practically feasible for soil layers with incomplete layers of rock or rocks with voids or cobblestones.
- The HDD works best in solid rock or sedimentary materials.
Directional Boring Versus Traditional Boring
Traditional boring methods like trenching or open cut is a viable option only when the ground above the utilities is allowed to be disturbed. The area must be free from buildings, rivers, or roads to perform traditional boring. While directional boring can be used in the same situation without the need to disturb the utilities above.
Another important difference between directional and traditional boring method is the cost. The cost of traditional boring is less when compared to directional boring. Though traditional boring is cheap, its final results have limitations when compared with directional boring. Directional boring guarantees quality and a perfect finish to the project.
Advantages of Directional Boring
The main advantages of directional boring are:
- Directional boring reduces soil disturbances.
- HDD is a form of underground construction that allows the site to stay clean and free from patchy areas.
- The technique reduces the contamination of groundwater. This ensures higher safety compared to traditional boring methods.
- Directional drilling is an eco-friendly method as it protects the ecosystem and the adjacent areas.
- Directional boring is less influenced by the weather conditions of the site.
FAQs
Directional boring or horizontal directional drilling (HDD) is a trenchless technology employed to install underground pipes without impacting the area above the borehole.
The types of pipes installed using directional boring are- PVC, ductile iron, polyethylene, steel, and polypropylene types.
The main advantages of directional boring are:
1. Directional boring reduces soil disturbances.
2. HDD is a form of underground construction that allows the site to stay clean and free from patchy areas.
3. Directional boring reduces the contamination of groundwater. This ensures higher safety compared to traditional boring methods.
4. Directional drilling is an eco-friendly method as it protects the ecosystem and the adjacent areas.
5. Directional boring is less influenced by the weather conditions of the site.
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