Cementation effect evaluation of MICP sand solidification via electrical resistivity

There is no simple and feasible method to evaluate the on-site cementation effect of microbially induced calcium carbonate precipitation (MICP). Therefore, this study uses a convenient and non-destructive electrical resistivity method to evaluate the cementation effect of MICP sand solidification. First, the relationships of resistivity of MICP-solidified sand columns and porosity, water content, and calcium carbonate (CaCO₃) content are studied. The relationship between the resistivity and the unconfined compressive strength of the solidified sand column is then studied. The comprehensive parameter is proposed to represent the porosity, water content and CaCO₃ content of the solidified sand column, and the relationship between the comprehensive parameter and the resistivity or strengths is studied. Finally, a resistivity model for sand column solidified by MICP is proposed. The results show that the electrical resistivity increases with the increasing porosity, and it decreases with the increasing water content and also decreases approximately linearly with the increasing CaCO₃ content. The electrical resistivity also has a good correlation with its related properties. The results demonstrate that the electrical resistivity method is an effective method to evaluate the cementation effect of MICP sand solidification, which can be used in the field application.