Directional drilling

Suundpuurimine var.2The method can be used to construct pressured pipes, self-flowing short sections of pipes and sleeve pipes. The equipment consists of the following: drill press, mixer or compressor, location devices.

The first stage is pilot drilling. The suitable drill head is selected according to soil conditions. In pilot drilling, the location of the drill head is verified with a location device. This allows the operator to direct the drill head on the desired trajectory. During drilling, drill rods are connected to guide the drill head and direct special drill mix into the drill head. The composition of drill mix depends on the type of soil. When the drill head has reached the desired destination, it is replaced by an extender, behind which a retractable pipe is connected – usually a polyethylene pipe. Then the pipe is pulled into the pilot channel, where the extender in front enlarges the channel and directs drilling liquid into the channel. This decreases friction on the pipe and removes soil from the channel.

For pipes with larger diameters, so-called pre-extension is used before inserting the pipe to decrease tensile force and enlarge the channel “step by step”.

Directional drilling can be done from ground to ground (e.g. installing cable sleeves) or from pit to pit.

Pros (+) Cons (-)
Can be used in all types of soil, incl. limestone and granite Prior investigation of soil necessary
Minimal trace of diggings and cost of restoration (lower cost in many ways compared to open diggings)
Long stretches of installation
Installation reports for the location of the pipe