Centrifuge modelling of piled-rafts under generalised loads
Centrifuge modelling of piled-rafts under generalised loads
Recent theoretical, numerical, and experimental studies have contributed to a better understanding of the ultimate behaviour of pile groups under combined vertical, moment, and horizontal loads. However, the interaction mechanisms occurring at failure within the piles-raft-soil system are still not fully understood and, therefore, the design of piled rafts is typically carried out neglecting the contribution of the connecting raft to the overall capacity of the foundation. This work presents the results of centrifuge tests on small-scale models of piled rafts embedded in clay and subjected to combined loads in undrained conditions, carried out to investigate the main factors governing their behaviour at failure. The tests were carried out on 3×3 piled foundations, consisting of miniature reinforced concrete (RC) piles rigidly connected to a Perspex raft embedded into a uniform layer of Speswhite Kaolin. The RC piles were made of a mortar of cement, water and sand, reinforced using a stainless-steel cage consisting of longitudinal bars and a confining helicoidal wire. Laboratory tests were performed to characterise the structural resistance of the miniature RC piles under combined axial and bending loads using a modified four bending point apparatus. Centrifuge tests were carried out at 100g, each including different model foundations, with different loading conditions. The vertical load was applied as a dead load, and the foundations were brought to failure under displacement control applying a horizontal displacement with different eccentricities. It was observed that the contribution of the raft expands significantly the failure domain of the foundation with respect to the case of the pile group.
Francesco Potini; Giulia Viggiani; R. Conti
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Session 6: Onshore and offshore foundation systems
https://doi.org/10.53243/ICPMG2026-35