Prediction of the long-term settlement of the structures built on a reclaimed coral reef island: an aircraft runway

Abstract

Airport runways built on reclaimed coral calcareous sand foundation on coral reef islands is a type of important infrastructure for marine science observation, marine disaster relief, and marine supplies. Creep behavior of coral calcareous sand foundation under long-term loading applied by overlying structures could cause continuous foundation settlement; and excessive settlement may affect the normal service ability of airport runways built on coral reef islands. In this study, it is aimed to predict the long-term settlement of an airport runway built on a reclaimed coral reef island in the South China Sea (SCS) adopting a finite element method. Firstly, two improved Burgers creep models are proposed based on some laboratory triaxial test results; and then, they are embedded into the finite element software ABAQUS using the User Material Subroutine (UMAT) interface. Secondly, the two proposed improved Burgers creep models are validated by a series of triaxial creep tests for the coral calcareous sands sampled from a reclaimed coral reef island in SCS. Meanwhile, the parameters describing the creep behavior of the coral calcareous sands in SCS are calibrated for the subsequent numerical analysis. Thirdly, the long-term settlement of an airport runway built on a reclaimed coral reef island in SCS is numerically predicted adopting the two proposed improved Burgers creep models and the calibrated parameters. The computational results show that the settlement of the airport runway is in the range of 6.7 to 19.9 mm in the future 50 years, satisfying the requirement of Chinese design code MH/T 5027-2013. Finally, parametric analysis is performed to screen the significance and sensitivity of the parameters describing the creep behavior of the coral calcareous sands.