Failure behaviour of pile-type SCP improved ground under vertical loading

摘要

SCP is one of the most commonly used methods of treating soft clay layers due to its cost advantages in the improvement of performance, but today’s economic constraints and construction restrictions mean that there is a need to further minimize the improvement area and reduce the replacement ratio. Discussions are currently under way on the use of T-shaped and/or low-replacement SCP improvement. However, the effects of the improvement depth and replacement ratio on stability remain unclear. In this study, T-shaped and low-replacement SCP improved ground under vertical loading was subjected to a variety of centrifuge model tests and numerical analysis in order to investigate the failure mechanism. The outcomes indicated that a wedge-shaped rigid soil area formed under the loading plate, and that sand piles bent outward in passive soil areas. The numerical analysis clarified the failure mechanism of the improved ground under vertical loading. In addition, the bearing mechanism indicated that appropriate reduction of the improvement area has little influence on the bearing capacity and the failure mode when resistance beneath and lateral to the wedge-shaped rigid soil area is ensured.