| There exists a ground improvement technology that uses calcium carbonate precipitated from carbon dioxide generated by microbial metabolism and calcium sources in the pores of soil. It is known that the mechanical properties of the improved grounds correlate with the amount of calcium carbonate precipitation, but it is unclear how soil density influences calcium carbonate precipitation and the mechanical properties of the improved soil. Toyoura sand specimens of three relative densities are used to precipitate calcium carbonate through microbial metabolism. The injection-improved test and the triaxial test (consolidated-drained condition) are conducted to investigate calcium carbonate precipitation and the mechanical properties of the soil. The results show clearly that more calcium carbonate precipitation occurs in soil with lower relative density, but that in soil with higher relative density, the mechanical properties strengthen as calcium carbonate precipitation increases. |
