Abstract
The Fugu area of Yulin City, Shaanxi Province, China, is a typical Pisha sandstone region that has long faced severe soil erosion issues. While traditional engineering measures provide temporary relief, they struggle to achieve long-term ecological restoration. To address this, this study incorporated xanthan gum and superabsorbent polymer into loess soil at specific ratios for slope soil amendment. Strength and erosion resistance were evaluated through direct shear and 70 mm/h rainfall erosion tests, with reinforcement mechanisms examined via scanning electron microscopy. Results indicate that at a 0.3% XG and 0.15% SAP mixture ratio, the shear strength of samples reached a maximum of 162.75 kPa, representing an increase of approximately 35.6%, while cohesion increased by about 71.7%. Furthermore, under the combination of 0.6% XG and 0.3% SAP, slope soil loss mass decreased by 42.1%, while rainfall infiltration decreased by 32.8%. Combined with SEM results, the incorporation of XG and SAP enhances intergranular bonding by filling soil pore spaces, thereby strengthening particle cohesion and reducing slope erosion. It also increases soil cohesion and improves macroscopic shear performance. In summary, these findings provide valuable references for ecological protection of Pisha sandstone slopes.
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References
Liang, Z. et al. Pisha sandstone: Causes, processes and erosion options for its control and prospects. Int. Soil. Water Conserv. Res. 7, 1–8 (2019).
Li, R., Zhou, C., Fu, Y. & Zhu, J. Assessments of tensile characteristics and degradation mechanism of sandstone subjected to wetting–drying cyclic treatment. Rock Mech. Rock Eng. 56, 8965–8978 (2023).
Li, C. et al. Green and Low-Cost Modified Pisha Sandstone Geopolymer Gel Materials for Ecological Restoration: A Phase Review. Gels 10, 302 (2024).
Ping, Z. H. A. O. & Chenglin, T. Z. Origin, development and prospect of spray seeding technologyfor land greening. Sci. Soil. Water Conserv. 22, 9–21 (2024).
Zha, H., Zeng, L., Fu, H., Qiu, X. & Zhuo, P. A beneficial exploration and recommendations for the use of hydrophobic materials in ecological protection of strongly weathered carbonaceous mudstone slopes. J. Clean. Prod. 532, 146966 (2025).
Xu, Y., Su, C., Huang, Z., Yang, C. & Yang, Y. Research on the protection of expansive soil slopes under heavy rainfall by anchor-reinforced vegetation systems. Geotext. Geomembr. 50, 1147–1158 (2022).
Zhang, X., Li, M., Yao, Z., Qin, L. & Meng, M. Study of loess ecological slope protection optimization measures and prediction of the erosion control effect. J. Geog. Sci. 34, 1083–1108 (2024).
Berninger, T., Dietz, N. & González López, Ó. Water-soluble polymers in agriculture: Xanthan gum as eco‐friendly alternative to synthetics. Microb. Biotechnol. 14, 1881–1896 (2021).
Li, B., Song, G., Kang, A., Kou, C. & Wu, X. Study on the Anti-Scouring Performance of a New Type of Cast-in-Situ Vegetation Concrete for Slope Protection. Available at SSRN 5014012.
Wang, L., Yao, Y., Li, J., Liu, K. & Wu, F. A state-of-the-art review of organic polymer modifiers for slope eco-engineering. Polymers 15, 2878 (2023).
Yao, D., Qian, G., Liu, J. & Yao, J. Application of polymer curing agent in ecological protection engineering of weak rock slopes. Appl. Sci. 9, 1585 (2019).
Kang, X., Xia, Z., Chen, R., Sun, H. & Yang, W. Effects of inorganic ions, organic polymers, and fly ashes on the sedimentation characteristics of kaolinite suspensions. Appl. Clay Sci. 181, 105220 (2019).
Yao, D., Qian, G., Yao, J., Liu, J. & Yu, X. Polymer curing agent in ecological protection design weak rock slope engineering application. J. Perform. Constr. Facil. 34, 04019115 (2020).
Jiang, T., Zhao, J. & Zhang J.-r. Splitting tensile strength and microstructure of xanthan gum-treated loess. Sci. Rep. 12, 9921 (2022).
Soldo, A., Miletić, M. & Auad, M. L. Biopolymers as a sustainable solution for the enhancement of soil mechanical properties. Sci. Rep. 10, 267 (2020).
Bian, X. et al. Changes in strength, hydraulic conductivity and microstructure of superabsorbent polymer stabilized soil subjected to wetting–drying cycles. Acta Geotech. 17, 5043–5057 (2022).
Fortuna, B., Logar, J., Sorze, A., Valentini, F. & Smolar, J. Influence of xanthan gum-based soil conditioners on the geotechnical properties of soils. Appl. Sci. 14, 4044 (2024).
Sorze, A., Valentini, F., Dorigato, A. & Pegoretti, A. Development of a xanthan gum based superabsorbent and water retaining composites for agricultural and forestry applications. Molecules 28, 1952 (2023).
Venda Oliveira, P. J. & Cabral, D. J. Behaviour of sand stabilised with xanthan gum under unconfined and confined conditions. Proc. Institution Civil Engineers-Ground Improv. 176, 3–13 (2023).
Adjuik, T. A., Nokes, S. E., Montross, M. D. & Wendroth, O. The impacts of bio-based and synthetic hydrogels on soil hydraulic properties: A review. Polymers 14, 4721 (2022).
Maghchiche, A., Haouam, A. & Immirzi, B. Use of polymers and biopolymers for water retaining and soil stabilization in arid and semiarid regions. J. Taibah Univ. Sci. 4, 9–16 (2010).
Yang, Q., Pei, X. & Huang, R. Impact of polymer mixtures on the stabilization and erosion control of silty sand slope. J. Mt. Sci. 16, 470–485 (2019).
Ng, C. W. W., Guo, H., Ni, J., Zhang, Q. & Chen, Z. Effects of soil–plant-biochar interactions on water retention and slope stability under various rainfall patterns. Landslides 19, 1379–1390 (2022).
Lee, M. H., Lin, H. H. & Jien, S. H. Effects of biochar application on vegetation growth, cover, and erosion potential in sloped cultivated soil derived from mudstone. Processes 10, 306 (2022).
Ministry of Water Resources, China, and Nanjing Hydraulic Research Institute. Vol. GB/T 50123 – 2019 717 (Ministry of Housing and Urban (Rural Development of the People’s Republic of China; State Administration for Market Regulation, 2019).
Chang, I., Im, J., Prasidhi, A. K. & Cho, G. C. Effects of Xanthan gum biopolymer on soil strengthening. Constr. Build. Mater. 74, 65–72 (2015).
Chang, I. & Cho, G. C. An Tran, T. P. Water-retention properties of xanthan-gum-biopolymer-treated soils. Environ. Geotechnics. 11, 152–163 (2024).
Faruqi, A., Hall, C. A. & Kendall, A. Sustainability of bio-mediated and bio-inspired ground improvement techniques for geologic hazard mitigation: A systematic literature review. Front. Earth Sci. 11, 1211574 (2023).
Ma, H. & Ma, Q. Experimental studies on the mechanical properties of loess stabilized with sodium carboxymethyl cellulose. Advances in Materials Science and Engineering 9375685 (2019). (2019).
Gu, J., Ni, J., Liu, S. & Chen, Y. Shear strength of biopolymer amended soil under freeze-thaw cycles: Experimental investigation and DEM modeling. Engineering Geology, 108108 (2025).
Wang, Q. et al. Microstructure and reinforcement mechanism of lignin-modified loess. J. Mater. Civ. Eng. 32, 04020319 (2020).
Tang, C. S., Shi, B. & Zhao, L. Z. Interfacial shear strength of fiber reinforced soil. Geotext. Geomembr. 28, 54–62 (2010).
Yang, Y. et al. Effects of long-term super absorbent polymer and organic manure on soil structure and organic carbon distribution in different soil layers. Soil Tillage. Res. 206, 104781 (2021).
Xuan, K. et al. Effects of organic amendments on soil pore structure under waterlogging stress. Agronomy 13, 289 (2023).
Tejada, M., Garcia, C., Gonzalez, J. & Hernandez, M. Use of organic amendment as a strategy for saline soil remediation: Influence on the physical, chemical and biological properties of soil. Soil Biol. Biochem. 38, 1413–1421 (2006).
Weng, Z., Yu, J., Deng, Y., Cai, Y. & Wang L.-n. Mechanical behavior and strengthening mechanism of red clay solidified by xanthan gum biopolymer. J. Cent. South. Univ. 30, 1948–1963 (2023).
Ningning, Z. H. A. O., Chengzong, H. C. H. E., Chengzong, H. E. & Chengzong, H. E. Anti-cracking and Anti-scouring Characteristics of Clayey SoilImproved by Palm Silk. HENAN Sci. 41, 476–485 (2023).
Funding
This research was funded by “Natural Science Foundation of Science and Technology Department of Shaanxi Province” (S2024-JC-YB-2574) and “Xi’an Science Technology Bureau Fund” (23NYGG0050).
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C.X analyzed the data and drafted the manuscript; ND.D and ZX.M revised the manuscript and guided the experimental implementation; SL.Z and XJ.B were responsible for experimental operations and statistical analysis of the results; C.X participated in the preparation of figures and tables. All authors reviewed the manuscript.
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The authors confirm that informed consent for field soil sampling activities in this study was obtained from relevant local authorities. We recognize that formal written permission should be secured in advance for future research and will implement this as standard operating procedure. All samples collected in this study were used exclusively for this non-commercial scientific research.
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Deng, N., Xu, C., Bai, X. et al. Study on the strength and erosion resistance of soil-amended substrates for rock slopes in Fugu County. Sci Rep (2026). https://doi.org/10.1038/s41598-026-47030-7
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DOI: https://doi.org/10.1038/s41598-026-47030-7
