Dispersion, mechanical, hydrophysical properties and mechanistic analysis of improved dispersive soil using guar gum

Dispersive soil has poor engineering geological properties, which can lead to various geological hazards in practical engineering projects. This study utilizes guar gum, an eco-friendly biopolymer with great potential in soil improvement, to improve dispersive soils in western Jilin. Guar gum powder was added to the dispersive soil at dry mass ratios of 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, and 5%, and cured for 1, 3, 7, 14, and 28 days. The improvement effect was comprehensively evaluated by dispersion identification test, unconfined compressive strength test before and after immersion, disintegration test, matric suction test, and permeability test. The mechanism of guar gum in improving dispersive soil was further explained from the microscopic point of view by particle size analysis, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that more than 1.5% guar gum proportion was effective in eliminating soil dispersion. The cured soil had the best mechanical properties at 3.0% guar gum content. With the incorporation of guar gum, the hydrophysical properties of the soil were also improved. Guar gum wraps around soil particles, forming bridges through the hydrogel. Additionally, it fills the voids in the soil, leading to a denser aggregation of the soil particles. In conclusion, guar gum, as an environmentally friendly biopolymer, has a positive effect on the improvement of dispersive soils. The research results will provide theoretical guidance for engineering construction in dispersive soil areas.