According to Wikipedia, deep foundations are a type of foundation used to transfer the loads of a structure to deeper, stronger soil or rock layers when the surface soil cannot safely support the weight of the structure. One of the most common types of deep foundation is piling, where long columns made of timber, steel, reinforced concrete, or prestressed concrete are driven or drilled deep into the ground. Deep foundations are widely used in the construction of high-rise buildings, bridges, towers, and other heavy structures to provide stability and reduce settlement.