Mechanical behavior and strengthening mechanism of loess stabilized with xanthan gum and guar gum biopolymers

Abstract

The structural properties of loess are susceptible to change when subjected to external loads and complex environments, leading to various geological disasters. To investigate the mechanical behavior and strengthening mechanism of loess stabilized with biopolymers such as xanthan gum and guar gum, especially for soils with low bearing capacity and stability in engineering applications, we conducted research on the improvement of soil with xanthan gum and guar gum, tests including unconfined compressive strength, disintegration, direct shear, and microstructure tests were conducted. Among the four different dosages of biopolymers (0%, 0.5%, 1%, 2%) and four different curing ages (1 day, 3 days, 7 days, 14 days), the 2% content of biopolymer and 14 days had the greatest impact on the mechanical properties of loess, Both the compressive and shear strength, as well as the water stability of solidified loess, improve with higher content of xanthan gum and guar gum or prolonged curing time; however, the disintegration rate decreases. Microscopic analysis indicates that the biopolymers effectively fill the gaps between soil particles and attach to the particle surfaces, forming fibrous and reticular structures that improve the interparticle bonding and ultimately increase the strength and water stability of the loess. Xanthan gum and guar gum biopolymers can improve the mechanical properties and water stability of loess, enhance the erosion resistance and improve the water-holding capacity. These outcomes suggest that guar gum and xanthan gum biopolymers have the potential to serve as environmentally sustainable alternatives to conventional soil stabilizers.