When the ground beneath the earth’s surface cannot support a foundation, a construction crew must utilize drilling methods to accomplish a deeper, more stable, and secure foundation. In this quick guide to deep foundation drilling methods, we’ll go over continuous flight auger drilling, Kelly drilling, down-the-hole drilling, and grab drilling. Keep reading to learn more about these various methods.

Continuous Flight Auger Drilling

Use the continuous flight auger method when your construction project calls for pre-drilling and creating holes for cast-in-place piles. A foundation drilling auger with continuous flighting will continuously convey material to the top of the hole while drilling to reach the correct depth in one application. This method is a dry rotary drilling technique that works for most rock and soil types.

Kelly Drilling

Continuous flight auger drilling is a dry rotary method, and Kelly drilling is the most common in this category. The operator uses a Kelly bar and drill rod to produce bored piles with a large diameter. Augers, buckets, and core barrels, among other tools, convey the loose soil and rock to the surface of the borehole. Kelly drilling also works on nearly all types of rock and soil.

Down-the-Hole Drilling

Are you trying to build a foundation for a construction project, but boulders and heavy or hard rock are in the way? The down-the-hole drilling method is perfect for this situation. By mounting a hammer on a drill bit, you can use compressed air to pump the bit and break up the rock. The drill bit cuts the stone in its path while rotating and carries the drill cuttings to the borehole’s surface.

Grab Drilling

Grab drilling is one of the oldest deep foundation drilling methods. By using a pre-placed casing in the ground, a crane with a claw on the end is forcefully driven into the earth. The claw closes around the ground material and raises it to the surface for removal. You must repeat this process until you reach a suitable depth for the foundation.

The type of deep foundation drilling method you choose depends on the landscape of your project and the type of rock or soil you’re working with. For example, use down-the-hole drilling for hard rock and Kelly drilling for soft-to-medium-soft soils. Be mindful of the method you choose for your project—you must create a stable and secure foundation for the utmost safety. Which foundation drilling method do you utilize the most?