ABSTRACT
Evaluation of pile driving feasibility in weak carbonate rocks such as calcarenite requires an estimation of the penetration resistance. Results from an experimental programme are presented during which open-ended model pipe piles were jacked into large intact calcarenite blocks. The failure mechanisms at the pile toe and shaft were characterized. A significant feature of the penetration resistance was its oscillations with trough values as low as 10% of the peak values. Heterogeneity of the block was ruled out as a possible cause of the oscillations after a careful examination. Such behaviour was attributed to repeated calcarenite failures inside the pipe after some incremental penetrations of the pipe. The failure mechanism was confirmed by observing that disk-like fragments were generated inside the pile. At the outer pile-calcarenite interface, a region of crushed material formed. Contributions of pipe shaft and toe annulus to the jacking resistance were evaluated.
