A Bio-Chemo-Hydro-Mechanical Model for the Simulation of Biocementation in Soils: One-Dimensional Finite Element Simulations
Year: 2024
Type: article
Abstract: Microbially induced calcite precipitation is a soil improvement technique in which bacteria are used to produce calcium carbonate (biocement), precipitated after the hydrolysis of urea by the urease enzyme present in the microorganisms. This technique is becoming popular, and there have been several real cases of its use; however, the dosages and reaction times used to attain a required percentage of biocement mainly stem from previous experimental tests, and calculations are not performed. Thus, it is fundamental to have more robust tools and the existence of numerical models able to compute the amount precipitated, such as the one proposed in this paper, can be an important contribution. A two-phase porous medium model is created to analyse the precipitation process. The solid phase contains soil particles, bacteria and biocement, while the fluid phase contains water, urea and other dissolved species. A coupled bio-chemo-hydro-mechanical finite element formulation is defined, embodying the biochemical reaction, water seepage, the diffusion of species and soil deformation. The main novelties of this study are as follows: (i) porosity changes are computed considering the generation of solid mass due to biocement precipitation, and, therefore, soil permeability is updated during the calculation, with these highly coupled equations being integrated in time simultaneously and not sequentially; and (ii) the model is calibrated with experimental tests conceived especially for this purpose. The model is then used to compute the biocement precipitated in a sand column simulating a real experimental test. The results of the simulations present a distribution of biocement along the column closer to that observed in the experimental tests, validating the model.
Source: Mathematics
DOI: 10.3390/math12203267
Authors: Victor Scartezini Terra, Fernando M. F. Simões, Rafaela Cardoso
Institutions: University of Lisbon, Instituto Superior Técnico
Language: English
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,955
Awards: Mecanismos de fixação e durabilidade do tratamento de solos por biocimentação. Aplicação a um talude real para evitar ravinamento., Modelling of Biocementation in soils using chemo-hydro-mechanical coupled analysis., Instituto de Investigação e Inovação em Engenharia Civil para a Sustentabilidade
OpenAlex ID: W4403516263