This study explores seismic reinforcement techniques for road bridge pile foundations in volcanic ash ground. The proposed method involves encircling the pile foundation with a grid-form ground improvement wall for liquefaction countermeasures without direct contact with existing structures. Centrifuge model tests on commonly used road bridge pile foundations assessed the effects of different spacings and improvement strengths of the grid-form ground improvement wall on liquefaction countermeasure efficiency and the impact on existing piles. Results indicate that, irrespective of pile type or stiffness, the proposed technique had no significant impact on existing bridge superstructures. A recommended grid spacing of 7.0m or less, with an outermost pile center distance of 2.0m or more, was identified as suitable for achieving non-invasive reinforcement and effective counteraction of the reduction in horizontal subgrade reaction coefficients due to liquefaction, with sufficient performance achieved by adjusting the improvement strength and layout within this range.
5th European Conference on Physical Modelling in Geotechnics (ECPMG2024)
Onshore and offshore foundation systems