For construction contractors, the stability of a building very much depends on the integrity of the building's foundation. If contractors build on a weak foundation, then the building does not hold. However, some factors are out of the control of a contractor, especially in projects where the soil is not stable. In such projects, foundation piles are the preferred means of stabilising the foundation. That said, there are several different drilling methods for deep foundations, with each technique suited for specific needs. An understanding of these techniques allows contractors to build quality foundations for their clients. Read on.
Kelly drilling is a foundation boring technique that stands out among the dry rotary drilling methods. Since the procedure uses large drilling bits, it is best suited for foundation piles of large diameters for added strength. It makes the approach the most suitable foundation drilling technique for all types of soil and rock. Notably, the dirt is extracted from the holes via short rotary drilling bits, like augers and core barrels, during drilling. One element that makes the Kelly drilling method different from other techniques is the telescopic drill rod, which facilitates vast drilling depths. Usually, Kelly drilling is best for foundation constructions on soft soil where great depths and large foundation piles are critical.
Continuous Flight Auger Drilling
It is another deep foundation drilling method that is suitable for pre-drilling and also for the installation of cast-in-place piles. The rocks and soil, during drilling, are loosened and carried via the continuous spiral action of the flight auger. To protect the bored holes from crumbling while drilling the wall, auger flights with drill cuttings offer the necessary support. Unlike the Kelly drilling method, drilling with a continuous flight auger allows contractors to dig into the ground in a single continuous process. You, therefore, save time because you do not have to change the augers for different depth. However, you have to use an auger that is longer than the depth of the hole being drilled.
Full Displacement Drilling
The full displacement drilling technique is a bespoke version of the continuous flight auger drilling technique. However, it is solely used in projects where the soil is shifty, and thus the use of cast-in-place piles is necessary. A significant difference between the full displacement foundation drilling technique and other methods is that the surrounding soil in the holes is only displaced and not conveyed to the surface. Rather than a continuous auger, full displacement drilling is done using a smooth casing that is fitted with a displacement body at the lower end.