#DIRECTIONAL DRILLING FOR DUMMIES FREE#
HDD is a form of underground construction that allows the site to stay clean and free from patchy areas.Directional boring reduces soil disturbances.The main advantages of directional boring are: Directional boring guarantees quality and a perfect finish to the project. Though traditional boring is cheap, its final results have limitations when compared with directional boring. The cost of traditional boring is less when compared to directional boring. While directional boring can be used in the same situation without the need to disturb the utilities above.Īnother important difference between directional and traditional boring method is the cost. The area must be free from buildings, rivers, or roads to perform traditional boring. Traditional boring methods like trenching or open cut is a viable option only when the ground above the utilities is allowed to be disturbed. The HDD works best in solid rock or sedimentary materials.ĭirectional Boring Versus Traditional Boring.HDD is not practically feasible for soil layers with incomplete layers of rock or rocks with voids or cobblestones.
The types of pipes that can be installed using directional boring are- PVC, ductile iron, polyethylene, steel, and polypropylene.It can be employed for a variety of soil conditions.Directional boring is employed when the trenching or traditional excavation process is not practical.It is a type of bentonite that is easily mixed with water, resulting in a smooth drilling fluid that works well in different types of soil.Image Courtesy: Pinnacle Construction Features of Directional Boring This form of bentonite has proven its worth over many years. The drilling fluid to be used is Quik-gel or Wyoming bentonite. If the reaming is done too quickly, sand deposits may occur because the speed of the reaming mixture becomes lower than the speed required to transport the sand. The purpose of the swivel is to prevent the tube from rotating.ĭuring the reaming it is important to respect the calculated reaming time, which is calculated on the basis of the quantity of soil to be transported and the capacity of the pump that pumps the bentonite. The figure on the right shows how the jet at the front of the drill head loosens the sand and, by means of the drilling fluid, drives the sand out of the hole.Īfter the pilot drilling, a reamer is used to enlarge the borehole so that the tube to be installed can be pulled out.ĭuring the final reaming stage, the pipe is attached to the reamer by means of a swivel and is pulled into the borehole. When drilling the pilot hole, it is important that there is sufficient bentonite, so that you get a nice borehole and the following steps are easier to carry out.ī= Drilling fluid S=Round R=Returning fluid (= B+S) The position of the drill head is shown on a “clock”, which is visible to the driller via the measuring system.īy allowing the rods to rotate continuously, the drillhead will simply go straight ahead and not change direction. In this way, certain obstacles can be avoided. Turning the steering plate in a certain direction causes the drill head to follow.įigure 1 on the right illustrates how the steering plate (at an angle to the drillhead) steers the drillhead upwards.īy rotating the rods 90° to the left, right or 180°, the drillhead can be steered “unrestrictedly”. By rotating the steering plate, the drillhead will move in different directions. A “steering plate” is positioned on the drill head. In the pilot borehole, a drillhead with a jet is positioned at the end of the flushing tubes. Making the pilot bore is by far the most important step, as this phase determines the final route of the pipeline. Horizontal Directional Drilling – How does it work? Step 1: Pilot drilling
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