Soil degradation is caused by frequent extreme weather events. The acceleration of soil degradation is due to the development of soil fissures, which form additional channels for water evaporation. This article investigates the effects of different concentrations of xanthan gum on soil water retention and crack resistance. The results indicate that xanthan gum slows down soil cracking and effectively enhances soil crack resistance. This article defines the first batch of cracks that appear at the beginning of crack formation as “trunks”, cracks branching from the trunks as “branches”, and cracks splitting from the branches as “twigs”. As the content of xanthan gum increases, the trunks decrease and gradually turn into branches and twigs. Compared with soil with a xanthan gum content of 0.2%, the fractal dimension and fracture rate of soil samples decreased by 8.62%, 26.83%, and 35.45% and 2.75%, 13.74%, and 20.88%, respectively, when the xanthan content was 0.4%, 0.6%, and 0.8%. The final residual water content of the soil increased by 30%, 142%, and 192.5%, respectively. Compared with soil with a xanthan gum content of 0.8%, soil with a xanthan gum concentration of 0.2% showed a 150% increase in deceleration phase time. Xanthan gum affects the evaporation process and fracture behavior by altering the pore volume of the soil and generating biological aggregates. This study provides new ideas for the use of xanthan gum in solving soil cracking caused by dryness and water-retention problems.
Yang et al. (Tue,) studied this question.