Pile Capacity in Calcareous Sands: State if the Art

Abstract

Driven piles in calcareous sands may have only a small fraction of the capacity of driven piles in noncarbonate sands. This has become a particular problem in the offshore and coastal areas of Australia, India, Saudi Arabia, and the Caribbean. The great expense of load tests and/or remedial measures has caused many offshore operators to turn to drilled and grouted piles when these materials are encountered. The latter tend to have higher capacities but are also very expensive. This paper summarizes a review of the published literature pertaining to driven and drilled and grouted piles in calcareous sands. The summary includes a discussion of the relevant characteristics and behavior of calcareous sands, proposed soil classification schemes, and published pile load test results. It is concluded that pile capacities for driven piles are not only low but have a high variability. Generalized principles for classifying the soil, identifying controlling characteristics, and predicting pile behavior are badly needed. Drilled and grouted piles, on the other hand, appear to have capacities at least as great as driven piles in noncarbonate sands. Additional data are needed, however, to confirm these preliminary conclusions. Furthermore, alternative economical techniques for installation or postinstallation treatment to enhance pile capacity would be welcome.