There are several popular foundation drilling techniques used in construction, including:   1.    Auger drilling technique involves using a rotating helical screw blade to remove soil or rock from the ground. Auger drilling is commonly used for shallow foundations and is particularly useful for drilling through soft or loose soil. 2.    Drilled shafts, also known as bored piles, are deep, cylindrical foundations that are drilled into the ground using a large diameter drill bit. Drilled shafts are commonly used for large structures, such as high-rise buildings and bridges. 3.    Caissons are similar to drilled shafts but are typically larger in diameter and can be drilled deeper into the ground. Caissons are often used for heavy or tall structures, such as bridges, dams, and skyscrapers. 4.    Micropiles are small diameter piles that are typically less than 12 inches in diameter. They are often used in limited access or low overhead clearance areas, and can be installed in a variety of soil and rock conditions. 5.    Continuous flight auger piles are similar to auger piles. But instead of removing soil or rock from the ground, they use a continuous flight auger to drill into the ground while simultaneously injecting concrete or grout into the hole. They are commonly used for medium to large structures. 6.    Vibro stone columns are a ground improvement technique that involves inserting crushed stone into the soil using a vibrating probe. This technique is used to improve the load-bearing capacity of weak or compressible soils and is commonly used in foundation construction.   Overall, the choice of foundation drilling technique will depend on the specific needs and requirements of the project, as well as the soil and rock conditions at the job site. A qualified foundation contractor will be able to recommend the best drilling technique for a particular project based on these factors.