The rapid expansion of cities is driving the need to develop piled foundations which are able to support increasingly larger loads for the construction of high-rise buildings. Current research on piled foundations has focused on methods of reducing the size of piles whilst maintaining or increasing their capacity in an attempt to conserve the limited amount of underground space available. Generally, the ultimate capacity of a pile is achieved through shaft friction between the pile and the soil. The amount of undrained shear strength, su, of a soil that is mobilised by a pile shaft depends on the adhesion factor, a. For bored piles in clay, a varies between 0.35-0.50, suggesting that a large proportion of su along the pile shaft length is not mobilised. Recent research suggests that piles with a lower stiffness increase the proportion of su mobilised by allowing the pile to strain within the soil. Therefore, it would be beneficial to have a better understanding of the soil-pile interaction of lower stiffness piles in order to achieve higher working load capacities. A series of geotechnical centrifuge tests were undertaken on piles with varying axial stiffness in order to investigate this phenomenon. The tests were conducted at 50g at City, University of London, investigating the displacement of the piles under applied axial load.
Sabaliauskaite et al. (Wed,) studied this question.