Foundation-Pile Group

A pile foundation may consist of a group of piles, joined by pile cap at the top and typically spaced at 2 to 4 timers the pile diameter.

There are two modes of failure for pile group, namely individual pile failure and block failure.

During design, the distribution of axial load among the piles is assumed uniform.

However, center piles are expected to carry greater loads than perimeter piles in sand. The reverse is true for pile group in clay.

Block failure on the other hand, is more likely to occur in fine-grained soil rather than coarse-grained soil. It may be induced when the pile spacing is less than 2 to 3 times the pile diameter.