Physical and numerical study of load transfer mechanism of geotextile-reinforced sand fill over soft marine clay improved by deep cement mixed soil columns

Abstract

The Hong Kong International Airport has expanded its existing two-runway system to a three-runway system based on a reclamation project over a seabed of soft marine clay. In the reclamation area, a layer of load transfer platform (LTP) was designed with geosynthetic reinforcement to bridge the overlaid surcharge loadings of reclamation fills and underlaid marine clay improved by deep cement mixing method. In this study, firstly, a small-scale physical model test of geotextile-reinforced sand layer over soft marine clay improved by cement-treated soil columns was performed to investigate the load transfer mechanism among columns, soils, and geotextile under different surcharge loadings. The results from the scaled model test were then adopted to verify the parameters used in a finite element model established using PLAXIS. Furthermore, the finite element model was used to reveal the development of soil arching.