Effect of Pore–Fluid Chemistry on the Undrained Shear Strength of Xanthan Gum Biopolymer-Treated Clays

Xanthan gum (XG) biopolymer-based soil treatment is an effective improvement method. In this study, we explored the effect of XG on undrained shear strength clays (kaolinite and montmorillonite) in chemically distinct pore fluids. Among fluids tested, kaolinite was highest kerosene, followed by deionized (DI) water brine. This study hypothesized that interparticle forces interactions dominated clay. contrast, montmorillonite showed with DI water, brine likely due to increase thickness viscous double layer reduced also affected clays, possibly viscosity modification clay fabrics. increased (maximum observed sample XG-to-soil mass ratio 0.5%) via absorption. Simultaneously, decreased montmorillonite, XG-induced particle aggregation resulting from changes surface charges. 2-M-NaCl brine, content, regardless mineral types, owing salt-induced double-layer compression concurrent pore–fluid viscosity. However, unaffected constant both nonpolar kerosene suggests hydrating a prerequisite for its application treatment.