Stress-Dilatancy Behavior of MICP-Treated Sand

Biocementation of soil using microbial-induced carbonate precipitation has become a new approach for soil treatment. The biocemented sand behaves differently from uncemented sand. One of the major differences is the stress-dilatancy behavior. In this paper, the experimental data obtained from isotropically consolidated drained triaxial tests are presented. The data showed that the biocemented sand exhibited much higher dilatancy than uncemented sand of the same density in drained triaxial tests. The higher the calcium carbonate content, the higher the dilation. Higher dilatancy was also related to higher shear strength, which was mainly due to higher effective cohesion. The variation in effective cohesion with the calcium carbonate content is discussed. The stress-dilatancy relationship of biocemented sand can be interpreted under the framework of Rowe's stress-dilatancy theory: The biocemented sand behaved like dense sand in terms of the stress-dilatancy relationship.