There are several solutions engineers and contractors can choose from when a deep foundation is required. With a deep foundation the structure’s load is transmitted to soils that are deeper in the ground. A deep foundation is used when a shallow foundation is not possible, not practical, or will not carry the load. Examples are weak, unstable, or expansive surface soils. Two popular options for deep foundations are helical piles and drilled shafts, also known as drilled piers or caissons.
There is no equivalent for measuring torque directly in the tooling string. Using differential pressure (or pressure drop across the motor) can work if it is properly set up and calibrated, but keep in mind that pressure is being measured, not torque.