A study on ground improvement tecnique with in-situ microoganisms isolated from Japan

Abstract

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 in-situ microorganisms in the spots selected by this research.