Long-term behavior assessment of the pleistocene marine foundations considering the subsurface stratigraphy at large-scale offshore airport fill

Abstract

A series of elasto-viscoplastic finite element analyses were conducted to evaluate the long-term behavior of reclaimed Pleistocene deposits at the existing 1 st phase island of Kansai International Airport, as influenced by the construction of the adjacent 2 nd phase island, located 200 m offshore from the 1 st phase island. The geologically reliable foundation model, featuring an inclined base overlain by irregularly thick inclined Pleistocene deposits, is adopted for the numerical analyses. The geological reliable foundation model has been developed based on the results from elastic wave exploration with in-situ boring logs. Due attention is also given to the mechanisms such as the generation, dissipation, and propagation of excess pore water pressure in the reclaimed Pleistocene deposits resulting from the construction of offshore reclaimed airport islands. The mode of excess pore water pressure in the geologically reliable foundation with irregular thickness is extensively analyzed through comparison of the results performed for the horizontally even ground foundation model with constant thickness. The calculated performance is validated through a comparison with the in-situ measured results obtained from monitoring point 1 on the 1 st phase island.