Precipitation of Calcite by Indigenous Microorganisms to Strengthen Liquefiable Soils

Enrichments for indigenous microorganisms capable of hydrolyzing urea in the presence of CaCl2 were performed on potentially liquefiable saturated soils in both the laboratory and in situ. Following enrichment, treatment of soils with nutrients, CaCl2 and urea resulted in significant in situ precipitation of calcite, even at depth, by indigenous microorganisms. The biomineralized soils showed properties that indicate calcite precipitation increased their resistance to seismic-induced liquefaction.