HORIZONTAL DIRECTIONAL DRILLING (HDD)
1 THE METHOD
The horizontal directional drilling (HDD) is the most appropriate and modern technique for pipelines.
This is a technique in which open excavation is replaced by a precision guided drilling, technology carried out with the aid of a pressurized liquid jet.
It can be described as an advanced system for laying underground lines and can be used in crossings of rivers and canals, embankments, roads, highways and railways.
One of its main advantages is to minimize the destruction/excavation of roads and sidewalks, and reduce he inconveniences of excavation work: noise, dirt, obstruction of trafic, etc.
Our equipment allows us to install HDPE and Steel pipe up to 1400 mm indiameter for lenghts up to 2000 meters both in soils and in rock ground.
Step 1: Pilot Drill
A guided drill bit mounted with a hydro-mechanical system is used for the initial bore, making the pilot hole with the default path and depth.
Directional control of the head is three-dimensional, which allows obtaining a high precision in the outlet predefined.
Step 2: Boring
Then, the drill bit is replaced by a reamer which is drawn in the opposite direction by receding from the outlet to the base where the team is positioned, thereby widening the pilot bore.
This operation is repeated several times until it reaches the desired bore diameter.
Step 3: Shooting
A pull head coupled with an anti-rotation joint system is attached to pipe to be drawn. This pull head is then attached to the reamer that performs the last bore widening. This operation is performed gently and slowly to avoid damage to the pipes.
These may contain the drill fluids, such as bentonite or polymers with low environmental impact, but necessary in this case, since they act as a lubricant to reduce friction.