Boretunnelteknikk

Boretunnelteknikk, also known as microtunneling or horizontal directional drilling (HDD), is a trenchless technology used for installing underground pipelines. This method involves using a steerable drilling machine to create a pilot bore between two access points. Once the pilot bore is successfully completed and the desired path is confirmed, the drill head is replaced with a reamer. The reamer then enlarges the borehole to the required diameter. Finally, the product pipe is pulled back through the enlarged hole.

The primary advantage of boretunnelteknikk is its minimal surface disturbance. This makes it ideal for urban areas, environmentally sensitive locations, and areas with existing infrastructure where open-cut excavation would be disruptive and costly. The process is highly accurate, allowing for precise control of the pipeline's alignment and grade, even through complex geological conditions. It can be used to install a variety of utilities, including water and sewer lines, gas pipelines, and power cables.

The equipment used in boretunnelteknikk typically includes a drilling rig, drill pipes, a steering system, a mud mixing and recycling system, and a pulling mechanism. The drilling fluid, often a bentonite-based slurry, plays a crucial role in stabilizing the borehole, cooling the drill bit, and transporting cuttings to the surface. Different types of drill heads and reamers are available, allowing the technology to adapt to various soil types and rock formations. The technique's ability to overcome obstacles such as rivers, railways, and existing underground utilities without significant surface disruption contributes to its widespread adoption in modern infrastructure projects.