Abstract:
The growing demand for transport infrastructure often necessitates the construction of embankments and structures on soft or unfavourable ground conditions. In Southeast Queensland and Northern New South Wales, many highway projects are built through swampy, marine environments underlain by highly compressible clays. While managing long-term settlement during the pavement service life is a common design concern, the proximity of sensitive structures introduces additional challenges, particularly due to the lateral spread of soft soils. This paper presents the approach and findings of 3D numerical modelling using PLAXIS 3D, undertaken to assess the displacements and structural responses induced on a bridge pier and abutment resulting from the construction and consolidation of an adjacent 10 m-high road embankment in a recent Southeast Queensland project. The study highlights how construction sequencing, ground improvement techniques, and structural configuration influence the mitigation of long-term impacts on the structure. The results provide practical insights into the integrated geotechnical-structural design strategies for infrastructure in soft soil environments.