Study on Planting and Mechanical Properties of Clay Modified by Xanthan Gum and Guar Gum

Abstract

The improvement of clay by using xanthan gum and guar gum was studied, and the combined solidification effect of the two after compounding was investigated. Investigations were conducted on three variants of biopolymer-augmented clays: xanthan gum, guar gum, and their combination. Assessments through plant growth and direct shear experiments elucidated their planting and mechanical properties. Scanning electron microscopy (SEM) experiments were conducted to analyze the microstructure of clay before and after modification, and the mechanism of improvement of clay by the two biopolymers was discussed in combination with planting and mechanical tests. The experimental results demonstrated that the planting performance of clay could be significantly enhanced by incorporating appropriate amounts of xanthan gum, guar gum, and composite gum, but was inhibited at excessive dosages. These biopolymers mainly increased the cohesive force of the soil, improving its shear strength while minimally affecting the internal friction angle. Among them, the compounded gum showed the most significant improvement in shear strength of the clay. The cohesive force and shear strength were notably enhanced when biopolymers and plant roots were combined. Specifically, ryegrass roots in biopolymer-modified clay substrates further increased shear strength. The study demonstrates that biopolymers can effectively promote plant growth and improve soil strength under the combined action of plant roots. The research results demonstrate that a synergistic thickening effect is achieved when xanthan gum is combined with guar gum, leading to gel particles aggregating with soil particles to enhance the shear strength of the soil. The relationship between the improvement of shear performance of xanthan gum and guar gum modified clay and the microscopic internal changes, and provide a reference for further exploring the new ecological slope protection substrate of green environmental protection.