The correct answer is: D. All the above.
The bearing capacity of piles is the maximum load that a pile can support without failing. It is determined by a number of factors, including the type of pile, the soil conditions, and the depth of the pile.
Dynamic formulas are used to estimate the bearing capacity of piles based on the weight of the pile and the speed at which it is driven into the ground. Static formulas are used to estimate the bearing capacity of piles based on the load that is applied to the pile and the settlement that occurs. Pile load tests are used to determine the actual bearing capacity of a pile by applying a load to the pile and measuring the settlement that occurs.
The bearing capacity of piles is an important factor in the design of foundations. The bearing capacity of piles must be sufficient to support the load of the structure without causing excessive settlement.