One-dimensional compressibility of calcareous sand solidified with polyurethane foam adhesive
Yang Wu, Jie Huang, Jim Shiau, Qi Liu, Liwei Wen, Jueding Liu, Yingjie Hu, Norimasa Yoshimoto
Abstract
Calcareous sand, commonly used for hydraulic reclamation in island construction, is characterized by high porosity, low particle strength, and significant crushability. These properties may lead to potential foundation instability when subjected to substantial loads. This study examines the one-dimensional compressibility of calcareous sand solidified with polyurethane foam adhesive (PFA) through high-pressure compression tests, with a particular emphasis on the effects of particle gradation, polymer content, and relative density. The experimental results show that an increase in PFA significantly reduces vertical compression deformation, lowering compressibility by 20%. Uniform particle gradation provides the greatest resistance, decreasing the void ratio by 19.1%. Additionally, scanning electron microscopy (SEM) analysis reveals that PFA effectively bonds calcareous sand particles, resulting in formation of agglomerates that enhance resistance to vertical deformation. In comparison with unreinforced calcareous sand, PFA solidified specimens exhibit lower compressibility and higher yield stress. This demonstrates the effectiveness of polymer-induced solidification in enhancing mechanical stability for calcareous sand. These results highlight the effectiveness of PFA in improving the bearing capacity of calcareous sand foundations, providing valuable insights for island and reef construction projects.