Improvement of dispersive soil properties by enzyme-induced carbonate precipitation technology: Mechanical, microstructural, and statistical analysis

A novel method that combines reinforced enzyme-induced carbonate precipitation (REICP) was proposed to improve the mechanical properties of dispersive soil. Dispersive soils, which are highly susceptible to erosion caused by rainfall or seepage, pose significant environmental challenges. It is essential to focus on modifying dispersive soil using environmentally friendly methods. This study investigated the cohesion, internal friction angle, permeability, hydrostability test, and microstructure of dispersive soil treated with enzyme-induced carbonate precipitation (EICP)–MgCl 2 –xanthan gum (REICP), using statistical analysis. A series of laboratory experiments was conducted, including direct shear tests, permeability experiments, mud ball tests, simulated rainfall tests, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results showed that the combined treatment significantly enhanced the mechanical properties of dispersive soil. At the optimal ratio, cohesion increased by a factor of 2, and the permeability coefficient decreased by approximately 1.7 × 10 7 times. Additionally, the strength parameters gradually increased with curing time. Microstructural analyses indicated that calcite precipitation, pore filling, and ionic redistribution significantly improved the mechanical properties and hydrostability of the soil. Statistical analyses showed that EICP materials and xanthan gum increased soil cohesion, while magnesium chloride enhanced the internal friction angle and reduced porosity. This study integrates mechanical testing, statistical analysis, and microstructural evaluation to propose a sustainable and environmentally friendly method for improving dispersive soils. This approach reduces the use of chemical modifiers, minimizes environmental impacts, and demonstrates application potential in the stabilization of dispersive soils.