ABSTRACT
Microbially Induced Calcite Precipitation (MICP) has emerged as an innovative and sustainable soil improvement technique, which can improve liquefaction resistance. This paper presents a numerical study on the mechanical behavior of MICP cemented sands in cyclic triaxial shear tests by CFD-DEM simulations. Firstly, a novel three-dimensional cyclic contact model for cemented sand was proposed, associated with the time-dependent relationship describing the microbial denitrification reaction, and employed into a commercial DEM software, PFC3D 5.0. Secondly, undrained cyclic triaxial tests were simulated respectively on clean and cemented sands using the CFD-DEM coupling method. Finally, liquefaction resistance of specimens microbially-treated with different times were analyzed macroscopically and microscopically. The results show that the liquefaction resistance of MICP cemented sand is larger than that of clean sand. The increases of pore pressure ratio are suppressed significantly with decreases of mechanical coordination number and bond coordination number, due to different amounts of MICP cementation.
