MICP-induced reduction of bound water film thickness in granitic residual soil:Development and AFM validation of a soil mechanics-based predictive modelOA

The mechanical properties of clayey soils are intimately linked to Bound Water Content(BWC).Microbially Induced Calcium Precipitation(MICP),as an emerging technology for slope treatment and foundation engineering,has an unclear mechanism in the influence on BWC of soil.Therefore,quantitative analysis of the Thickness of the Bound Water Film(TBWF)—a direct microscale characterization of BWC—holds significant importance.To quantitatively analyze the influence of MICP technology on TBWF,this study proposes a TBWF prediction model based on soil mechanics theory and validates effectiveness through Atomic Force Microscopy(AFM)experiments.Taking Granite Residual Soil(GRS)as the research object,the study revealed that MICP technology significantly reduces TBWF:when the cementation solution concentration was 1.0 mol/L,TBWF decreased from 48.297 nm(untreated control)to 34.561 nm(1.0 mol/L treatment group),a reduction of 28.44%.Further investigations revealed that MICP treatment lowers the liquid limit moisture content of soil while increasing specific gravity,bound water density,and specific surface area.However,when the concentration exceeded 1.0 mol/L,TBWF rebounded due to suppressed urease activity.AFM experimental data showed high consistency with theoretical model predictions,verifying the model’s reliability.This study provides microscopic mechanism support for the application of MICP technology in geotechnical engineering fields such as landslide prevention and slope reinforcement,establishes a new method for quantitative analysis of the bound water film,and holds important significance for improving the effectiveness of geological disaster prevention and control.