Horizontal directional drilling or HDD, is a steerable trenchless method of installing underground pipes, conduits and cables in a shallow arc along a prescribed bore path by using a surface-launched drilling rig, with minimal impact on the surrounding area. Directional boring is uses when trenching or excavating is not practical. Directional boring minimizes environmental disruption. It is suitable for a variety of soil conditions and jobs including road, landscape and river crossings. Installation lengths up to 6,500′ (2,000m) have been completed, and diameters up to 48″ (1,200mm) have been installed. Pipes can be made of materials such as PVC, polyethylene, Ductile iron, and steel.
The process is used for installing infrastructure such as telecommunications and power cable conduits, water lines, sewer lines, gas lines, oil lines, product pipelines and environmental remediation casings. It is used for crossing waterways, roadways, shore approaches, congested areas, environmentally sensitive areas, and areas where other methods are costlier.
Directional boring is used instead of other techniques to provide less traffic disruption, lower cost, deeper and/or longer installation, no access pit, shorter completion times, directional capabilities, and environmental safety.
Directional Drilling can be done in any and all different types of soil. Dirt, clay, gravel, cobble, glacial till, volcanic rock and hard rock. These different type of soils can affect the lengths and size of the holes.