3 - Selection of Pile Type

Abstract

After the decision to use piles, the next question is which piles to use. There are many types of piles. Timber piles are cheap but difficult to install in hard soil. Steel piles may not be good in marine environments owing to corrosion. The chapter presents two cases to determine which piles to use. Timber piles are not suitable for granular soil with boulders underlain by medium-stiff clay owing to the existence of boulders in upper layers. The obvious choice is to drive piles all the way to the rock. The piles can be designed as end-bearing piles. If the decision is taken to drive piles to the rock for the above configuration, H-piles are ideal. Unlike timber piles or pipe piles, H-piles can go through boulders. Piles cannot be placed in soft clay, but they can be placed in medium-stiff clay. In this situation, piles need to be designed as friction piles. Pile capacity comes mainly from end bearing and skin friction. End-bearing piles, as the name indicates, obtain their capacity mainly from the end bearing, while friction piles obtain their capacity from skin friction.