Evaluation and Prediction for the Cementation Effect of MICP Based on Electrical Resistivity

Microbially induced calcium carbonate precipitation (MICP) is widely studied as a promising technique for ground improvement. However, there is no simple and feasible method to evaluate the treatment effects, which limits the extensive application of MICP. This study used electrical resistivity to evaluate and predict the treatment effects. The relationship between electrical resistivity and porosity, moisture content, or CaCO3 content of biotreated sand columns was first studied, and an empirical model of electrical resistivity and soil properties was then proposed to predict the porosity and unconfined compressive strength (UCS). The results showed that when the porosity increased, the electrical resistivity increased in the form of exponential power, but the fitting degree of the curve was lower. Moreover, the electrical resistivity decreased in the form of negative exponential power with the increase in moisture content or linearly decreased with the increase in CaCO3 content. The empirical model was capable of predicting the relationship between porosity or UCS and electrical resistivity after considering the uniform distribution of CaCO3. The treatment effects (porosity and UCS) of biotreated soils can be evaluated via electrical resistivity, which provides guidance for the application of MICP in the geotechnical engineering and civil engineering fields.