What are Deep Foundations?
Deep foundations are employed when the soil strata immediately beneath the structure are not capable of supporting the load with tolerable settlement or adequate safety against shear failure. Merely extending the level of support to the first hard stratum is not sufficient, although this is a common decision that is reached. Instead, the deep foundation must be engineered in the same way as the shallow foundation so that the soil strata below remain safe and free of deleterious settlement.
Deep foundations