Problems of soils and foundations are unique in marine environment. Soil dynamics has assumed a special role in the design of marine foundations. Pile foundations are subjected to wave loading and sea-quakes. The nature of loadings are different than for the on-shore environment. The deformations are large resulting in extremely non-linear behavior of soil-pile systems. The piles may lose contact with soil. In this paper, methods of analysis and design of piles in marine environment have been described. A comparison of predicted and measured response has been made for typical cases. Future research needs have been highlighted.
Piles are used extensively for supporting structures in seismic zones, machine foundations and offshore structures. The nature of pile response and pile interactions are quite different in all the three cases. Earthquake loading on piles under buildings may cause large deformations and soil nonlinearity. On the contrary, machines cause only small amplitudes of vibration, and soils may be assumed to behave as elastic materials. In offshore structures, the piles are especially long and slender with considerable freestanding lengths. The performance of a pile is significantly influenced by vibrations. Ghumman (1985) conducted a comprehensive series of model tests on penetration testing of piles under vertical vibrations. The penetration of the pile as well as the rate of penetration were found to increase with increase in dynamic force level. The energy supplied to a structure may be absorbed in the elastic and plastic deformations of both the substructure and the superstructure. Eccentric and inclined loads and moments may be induced on the pile heads and pile caps. Lateral forces on the superstructure are assumed to be transferred to the ground through the pile cap as lateral loads and moments, and the stability of the piles is checked against these loads.