Development of a Coupled BCHM-Model for Numerical investigations of MICP treatment of soil

Microbially induced calcite precipitation (MICP) offers the potential for the development of environmentally friendly and cost-effective solutions to a wide range of geotechnical engineering problems, from “improvement of the soft underground” to “control of groundwater contamination”. As a consequence of the bacteria-induced chemical reactions (BC) and the related hydro-mechanical responses (Fig. 1), the permeability in the MICP-treated soil can be significantly reduced, and the mechanical stiffness and strength can be remarkably improved. Since a large area, especially the complicated bio-chemical-hydro-mechanical couplings in MICP are currently not well understood, MICP treatments can be only demonstrated in the laboratory or in-situ tests.

This project aims to gain a better understanding of the coupled BCHM effects involved in MICP through numerical analysis. For this purpose, special attention is paid to the investigation of the mechanical constitutive model of the MICP-treated soil, and a fully coupled BCHM model will be developed. In this model, the soil is considered as full saturated porous media, which contains both fluid and solid phases. Multi-species, multi-physical processes i.e. reactive mass transport, solid deformation, and relevant couplings (Fig. 2) among those processes are considered. Finite element method (FEM) is applied to solve the mathematical equations involved in the model.