Micro-feature-motivated numerical analysis of the coupled bio-chemo-hydro-mechanical behaviour in MICP

Abstract

A coupled bio-chemo-hydro-mechanical model (BCHM) is developed to investigate the permeability reduction and stiffness improvement in soil by microbially induced calcite precipitation (MICP). Specifically, in our model based on the geometric method a link between the micro- and macroscopic features is generated. This allows the model to capture the macroscopic material property changes caused by variations in the microstructure during MICP. The developed model was calibrated and validated with the experimental data from different literature sources. Besides, the model was applied in a scenario simulation to predict the hydro-mechanical response of MICP-soil under continuous biochemical, hydraulic and mechanical treatments. Our modelling study indicates that for a reasonable prediction of the permeability reduction and stiffness improvement by MICP in both space and time, the coupled BCHM processes and the influences from the microstructural aspects should be considered. Due to its capability to capture the dynamic BCHM interactions in flexible settings, this model could potentially be adopted as a designing tool for real MICP applications.

Benchmarking a new TH2M implementation in OGS-6 with regard to processes relevant for nuclear waste disposal

“…As discussed, while some of the mentioned processes take place at different points in time (such as during operation or post-closure), others take place simultaneously or trigger each other. Biological and chemical processes also take place and could be incorporated in PDEs [54,55] but so far, they are not considered by the TH 2 M implementation or the benchmarks in this work. In order to simulate and quantify the impact of aforementioned processes on the system consisting of the repository and geosphere, they must be considered as a whole, coupled system and not separately.…”

Optimization of Injection Methods in the Microbially Induced Calcite Precipitation Process by Using a Field Scale Numerical Model

“…where C CaCO 3 and ρ CaCO 3 [ML −3 ] present the precipitated calcite concentration at the last time interval and the bulk density of precipitated calcite, respectively. The current permeability k n [L 2 ] in pore at time intervals is given by the traditional Kozeny-Carman (KC) equation [64],…”

Advancements in bacteria based self-healing concrete and the promise of modelling

“…Wang and Nackenhorst [161] performed numerical analyses of the coupled mechanisms in MICP for soil treatment and showed that the spatial distribution of the precipitated calcite is heavily dependent on the bacterial distribution and the relation between the reaction rate and mass transport rate. In further work, Wang and Nachenhorst [162] extended their model to include both the mechanical behaviour of the medium, including the increase in stiffness with MICP, and micro-structural effects on the reaction kinetics. The comparison of simulations with experimental data showed that the coupled bio-chemo-hydro-mechanical model gave a reasonable prediction of the test results.…”