Abstract: Hydraulic filled calcareous sand is usually used as foundation soil in island projects; and the marine environment surrounding has certain requirements for its permeability properties and seepage failure resistance. By mixing up microbial treatment solution and calcareous sand, microbially induced carbonate precipitation(MICP) technology might be applied to ground improvement through hydraulic progress. Permeability experiments of MICP treated and non-MICP treated calcareous sand with different relative densities are conducted and their permeability properties are evaluated. The results show that the mixing method could reduce the permeability of loose sand to the same level of dense sand; the critical hydraulic gradient increased substantially as well; and the mode of seepage failure changed from piping to flowing soil.

Key words: microbially induced carbonate precipitation(MICP) technology, calcareous sand, permeability, relative density, critical hydraulic gradient