Stress–Dilatancy Behavior of Biocementation-Enhanced Geogrid-Reinforced Sand

Abstract

The performance of geogrid reinforcement is largely influenced by the interlocking effect between the geogrid and soil. To enhance the performance of geogrid reinforcement in sand, a novel biocementation-enhanced geogrid reinforcement method was proposed. Biocementation could be carried out in situ via microbially-induced carbonate precipitation (MICP). To understand the mechanisms of the biocementation enhancement effect, the stress–dilatancy behavior of coarse sand (CS) that was treated with the biocementation-enhanced geogrid reinforcement method was studied through a series of triaxial tests. The test results showed that the interlocking effect between the geogrid and CS could be effectively improved when the CS around the geogrid was biocemented by the calcium carbonate (CaCO3) that was generated in situ through MICP. The stress–dilatancy behavior of geogrid-reinforced CS was significantly enhanced after biocementation. In addition, the interlocking effect that was provided by the geogrid could mitigate or even avoid brittle failure, restrain the further development of dilation, and enhance the mobilization of the friction strength (qf) of the biocemented coarse sand (Bio-CS) during shearing.