Kaolin-nucleation-based biotreated calcareous sand through unsaturated percolation method

Ocean development is an effective and practical way to address resource issues, such as food, fuel, and land shortage. The current work proposed using kaolin-based biocement to stabilize calcareous sand which is always the main component of the foundations of ocean engineering. Five kinds of kaolin concentrations (0 g/L, 10 g/L, 20 g/L, 50 g/L, and 100 g/L) were selected to stabilize calcareous sand via the unsaturated percolation method. Besides, the saturated strength was determined to mimic the practical situations. The results showed that treatment cycles and raw materials can be reduced to obtain a given saturated strength when moderate kaolin is added. That is, the cost-performance of the MICP is improved. Besides, the maximum attainable saturated strength can be enlarged when a small dosage of kaolin is added. The distribution of precipitate contents along with the height of the specimens was also determined by the buoyancy method. Furthermore, a critical permeability range, i.e., 1.11 ∼ 2.70 × 10 ^{- 4} m/s, is also distinguished from the permeability tests. The percolation method is not suitable for sand with a permeability smaller than this range.