Distribution and Properties of Microbially Induced Carbonate Precipitation in Underwater Sand Bed

Abstract

Microbially induced carbonate precipitation (MICP) is an innovative approach to strengthening and improving loose porous media. To advance MICP implementation in various geotechnical applications, the work presented herein investigates the distribution pattern of cementation and quantifies the improved material properties through experimental study. Sand was cemented by MICP via a double wall delivery system under submerged conditions and induced spherical flow in a large-scale box. The assessment on MICP-treated sand was conducted using shear wave velocity, hydraulic conductivity, mass of precipitated mineral, and cone tip resistance measurements. Experimental and numerical results were synthesized to evaluate the distribution of MICP with respect to reaction and transport rates. The shear wave velocity and the cone tip resistance were correlated to identify the level of cementation induced in the treated sand. Results included the general cementation pattern of MICP and the level of cementation as affected by induced seepage velocity and density. The relationship between the measured level of cementation, the shear wave velocity, and the cone tip resistance is presented and discussed.