Study on the improvement of clay properties by xanthan gum and its application on ecological slope protection engineering

ABSTRACT

Traditional substrate binder releases greenhouse gases during the production and application processes, and is detrimental to the vegetation restoration on slopes. To develop a new environmentally friendly soil substrate, this paper conducted a serial of experimental studies on the ecological function and mechanical properties of the xanthan gum (XG)-amended clay by plant growth tests and direct shear tests. The improvement mechanism of the xanthan gum (XG)-amended clay has also explored through microscopic examinations. Experimental results of plant growth tests show that the germination of ryegrass seeds and growth of seedlings can be effectively promoted by adding a proper content (≤2%) of XG into clay. Plants in substrates with 2% of XG grew best, while a high content (3-4%) of XG has an inhibitory effect on the plant growth. The results of direct shear tests illustrate that the shear strength and cohesion both increase with the increase of XG contents, while the internal friction has an opposite trend. The improve mechanism of the xanthan gum (XG)-amended clay were also explored by XRD tests and micro-scopic examinations. It is found that shows that XG does not react chemically to form new mineral components after mixing with clay. The mechanism of XG improving clay is mainly because the XG gel can fill the pores between clay particles, and enhance the cementation between clay particles. XG can enhance the mechanical properties of clay and offset the deficiencies of traditional binder. It can play an active role in the ecological slope protection project.

GRAPHICAL ABSTRACT

KEYWORDS:

• Xanthan gum
• plant growth test
• direct shear test
• microscopic mechanism
• ecological substrate slope protection technology

Disclosure statement

No potential conflict of interest was reported by the authors().

Data availability statement

Due to the nature of this research, participants of this study did not agree for their data to be shared publicly, so supporting data is not available.

Additional information

Funding

This research was supported by the National Natural Science Foundation of China (No. U22A20232, 52078195), the Innovation Group Project of Hubei Science and Technology Department (No. 2020CFA046) and the Innovation Demonstration Base of Ecological Environment Geotechnical and Ecological Restoration of Rivers and Lakes (2020EJB004).