Enhanced erosion resistance of granite residual soil through synergistic application of calcium lignosulfonate and microbial treatment

Abstract

MICP technology has been increasingly applied in geotechnical improvement, but its effectiveness in enhancing the erosion resistance of granite residual soil embankment slopes remains limited. This study proposes a novel approach combining CLS with MICP to enhance the erosion resistance of the soil. The effects of CLS on MICP-treated granite residual soil were evaluated through physical-mechanical tests, microstructural analysis, and artificial rainfall experiments. The results indicate that CLS significantly improved the physical and mechanical properties of the soil, increasing the maximum dry density from 1.72 g/cm³ to 1.83 g/cm³, unconfined compressive strength by 184.15 %, and surface penetration resistance by 43.91 %. The CLS-MICP combination enhanced erosion resistance, reducing erosion by 65.9 % under high rainfall intensity. Microstructural analysis revealed that CLS optimized the pore structure of the soil, optimizing the soil's pore structure, and reducing the median pore throat radius from 0.37 μm to 0.18 μm. Mechanistic analysis demonstrated that CLS enhanced the cementation strength and stability of the soil under rainfall erosion by promoting uniform CaCO₃ precipitation and reducing porosity. These findings provide both theoretical and technical support for the application of CLS-MICP technology in improving granite residual soil.