Boretunneling

Boretunneling is a trenchless method of installing underground pipelines. It involves using a drilling machine, known as a horizontal directional drill (HDD), to create a pilot hole along a predetermined path. Once the pilot hole is complete, a reamer is attached to the drill head to enlarge the hole to the desired diameter. Finally, the product pipe or conduit is pulled back through the reamed hole. This technique is employed to install pipelines for water, sewer, gas, and telecommunications, as well as for electrical conduits and other utilities.

The primary advantage of boretunneling is its minimal surface disruption. Unlike traditional open-cut methods, it requires only small entry and exit pits. This makes it ideal for crossing obstacles such as rivers, railways, highways, existing utilities, and environmentally sensitive areas where excavation would be difficult, costly, or undesirable. The process is also generally faster than open-cut methods for certain types of installations, and it can be performed in various ground conditions, including soil, rock, and mixed conditions, although specific equipment and techniques may vary.

The boretunneling process typically begins with site investigation and planning, including surveying the route and identifying potential subsurface obstructions. The HDD machine is then positioned at the entry pit, and the pilot bore is initiated. Guidance systems, often using electromagnetic locators or gyroscopic tools, are used to steer the drill head along the planned trajectory. After the pilot bore is successfully completed, the reaming and product pull-back stages follow. Careful monitoring of drilling pressures, fluid volumes, and bore stability is crucial throughout the operation to ensure a successful installation.