A STUDY ON GROUND IMPROVEMENT TECNIQUE WITH INSITU MICROOGANISMS ISOLATED FROM JAPAN
Keywords:
Microbial carbonate precipitation, Urease activity, Undrained cyclic triaxial test, LiquefactionAbstract
Damage by a liquefaction phenomenon was a problem in recent years, and the Great East
Japan Earthquake occurred on March 11, 2011 in Japan, and liquefaction damage occurred frequently. There
is also more adoption of Paris agreement in COP21 of the end of last year, and correspondence to a global
warming problem is also desired reduction in greenhouse effect gas amount of emission in the construction
field. Therefore considered ground improvement technology is necessary for the environment in Japan an
earthquake-ridden country. So we considered for practical use ground improvement techniques based
microorganism. That is watched as new liquefaction countermeasure technology for reduction in cost and the
point of view by which material and construction waste are reduction. In that ground improvement
techniques, it is difficult to using specific microbes. So we aimed at Microbial carbonate precipitation using
in-situ microorganism as the method to solve this problem. We made solidify sand using isolated
microorganisms in japan and Bacillus pasteurii the solidification ability becomes clear. We measured to
urease activity values of each microorganism. And we making of the test pieces, undrained cyclic triaxial test
and acid decomposition for using CaCO3(0.5mol/L). And we compared results. We understood two things
from examination results. 1) The difference occurs to liquefaction strength by urease activity value. 2) The
improvement effect of the liquefaction strength was admitted in Microbial carbonate precipitation using insitu microorganisms in the spots selected by this research.