Abstract: Biopolymers,as a novel environmentally friendly soil treatment and improvement material,have gained extensive applications in recent years,even in small quantities,due to their significant strengthening effect on soil. In this study,laboratory experiments were conducted on bauxite slime samples treated with different concentrations (0%,1%,1. 5%,and 2%) of guar gum. These experiments included testing for Atterberg limits,quick shear tests,nuclear magnetic resonance (NMR) experiments, and scanning electron microscopy (SEM). The experimental results indicate that with the increase in biopolymer content,both the liquid limit and shear strength of bauxite slime improved significantly. Specifically,the bauxite slime treated with 2% guar gum exhibited a 26% increase in liquid limit and a remarkable 182% increase in cohesion. NMR experiments revealed that guar gum could increase the moisture content of bauxite slime samples and create large internal pores within them. Additionally,SEM images confirmed the formation of a guar gum-bauxite slime matrix,thereby enhancing both the liquid limit and shear strength.

Key words: shear strength,liquid limit,guar gum,microstructural mechanisms,bauxite slime