Effect of Column Spacing and Dry Xanthan Gum Content on the Bearing Response of Soft Clay Improved with Sand Columns
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Abstract
Soft clay foundations commonly exhibit low bearing resistance and excessive settlement, while granular-column performance depends on both column geometry and infill properties. This study experimentally investigates the combined influence of column spacing and dry-blended xanthan gum (XG) content on the bearing response of soft clay improved with a 50 mm sand cushion and a 4 × 4 group of sand columns. Tests were conducted in a 700 × 700 × 800 mm rigid steel box using a 60 × 60 mm square footing. The clay was prepared at a target water content of approximately 25% and an undrained shear strength of approximately 17 kPa. Sixteen sand columns, 25 mm in diameter and 150 mm long, were installed at clear spacings of 20 and 35 mm, corresponding to Sc/d ratios of 1.80 and 2.40. XG contents of 0%, 0.5%, 1%, and 2% by dry sand mass were examined after three days of covered conditioning. Responses were compared at s/B = 11%. Untreated clay carried 98.24 kPa, while the sand cushion increased the pressure to 110.76 kPa. The highest response occurred at 35 mm spacing with 1% XG, reaching 174.15 kPa and BCR = 1.773. At 20 mm spacing, the best response occurred with 2% XG, reaching 129.09 kPa and BCR = 1.314. The results indicate a non-monotonic spacing–XG interaction, showing that spacing and XG content should be evaluated jointly. The best-performing tested configuration remains specific to the model conditions and requires confirmation through replicated and larger-scale testing.
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Abdelrahman, G.E., Youssef, Y.G., and Abd, M.E., 2026. Experimental study on the improvement of bearing capacity of soft clay by using reinforced sand cushion resting on encased stone columns. HBRC Journal, 22(1), pp. 36–51. https://doi.org/10.65800/2090-9934.1003
Alavi, S.M., Shakeri Talarposhti, S., Khodaei Ardabili, A.A., and Aghamolaei, M., 2024. Field study on unconfined compressive strength and drilling data of DSM columns: a machine learning approach. In International Conference on Transportation and Development 2024: Transportation Safety and Emerging Technologies, Atlanta, GA, USA, 15–20 June 2024, pp. 404–416. Reston, VA: American Society of Civil Engineers. https://doi.org/10.1061/9780784485514.036
Al-Hashemi, H.M.B., 2016. Bearing capacity and settlement of shallow foundation: Comparison of different approaches. Term Project Report, Master of Science in Geotechnical Engineering, Civil and Environmental Engineering Department, College of Engineering Sciences and Applied Engineering, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia. https://doi.org/10.13140/RG.2.2.23244.82560
Al-Kaisi, A.R., and Ali, H.H., 2013. Mathematical estimation for the bearing capacity of sand column inserted in soft clay soil. Engineering and Technology Journal, 31(5A), pp. 816–827. https://doi.org/10.30684/etj.31.5a2
Al-Kazzaz, Z.A., and Al-Obaydi, M.A., 2021. Effect of spacing between stone columns on the behavior of soft soil. E3S Web of Conferences, 318, Article 01006. https://doi.org/10.1051/e3sconf/202131801006
Al-Kubaisi, O.K.I., 2018. Prediction of the effect of using stone column in clayey soil on the behavior of circular footing by ANN model. Journal of Engineering, 24(5), pp. 86–97. https://doi.org/10.31026/j.eng.2018.05.06
Al-Saoudi, N.K.S., Al-Kaissi, M.M.M., and Al-Baiaty, S.E.K., 2013. Ordinary and encased stone columns with two different relative densities. Engineering and Technology Journal, 31(13A), pp. 2415–2432. https://doi.org/10.30684/etj.31.13a.2
Al-Subari, B.L., Hilal, A., and Ekinci, A., 2023. Life cycle assessment of soil stabilization using cement and waste additives. Construction and Building Materials, 403, Article 133045. https://doi.org/10.1016/j.conbuildmat.2023.133045
Andreou, P., Frikha, W., Frank, R., Canou, J., Papadopoulos, V., and Dupla, J.C., 2008. Experimental study on sand and gravel columns in clay. Proceedings of the Institution of Civil Engineers – Ground Improvement, 161(4), pp. 189–198. https://doi.org/10.1680/grim.2008.161.4.189
Askari, F., Gharib, M., Ranjbar Malidarreh, N., Esmaeilnia Amiri, M., and Soleimani Kutanaei, S., 2025. Investigation of self-healing process and strength of biopolymer-stabilized silty sand: Comparison of xanthan and Persian gum in geotechnical engineering. Carbohydrate Polymer Technologies and Applications, 11, Article 100914. https://doi.org/10.1016/j.carpta.2025.100914
ASTM D1143/D1143M, 2020. Standard Test Methods for Deep Foundation Elements Under Static Axial Compressive Load. West Conshohocken, PA: ASTM International.
ASTM D422, 2007. Standard test method for particle-size analysis of soils.
ASTM D854, 2014. Standard test methods for specific gravity of soil solids by water pycnometer.
ASTM D2974, 2014. Standard test methods for moisture, ash, and organic matter of peat and other organic soils.
ASTM D4318, 2017. Standard test methods for liquid limit, plastic limit, and plasticity index of soils.
ASTM D4972, 2019. Standard test methods for pH of soils.
ASTM D5907, 2018. Standard test methods for filterable matter (total dissolved solids) and nonfilterable matter (total suspended solids) in water.
Barman, D., and Dash, S.K., 2022. Stabilization of expansive soils using chemical additives: a review. Journal of Rock Mechanics and Geotechnical Engineering, 14(4), pp. 1319–1342. https://doi.org/10.1016/j.jrmge.2022.02.011
Bergado, D.T., Balasubramaniam, A.S., Fannin, R.J., and Holtz, R.D., 2002. Prefabricated vertical drains (PVDs) in soft Bangkok clay: a case study of the new Bangkok International Airport project. Canadian Geotechnical Journal, 39(2), pp. 304–315. https://doi.org/10.1139/t01-100
Black, J.A., Sivakumar, V., and Bell, A., 2011. The settlement performance of stone column foundations. Géotechnique, 61(11), pp. 909–922. https://doi.org/10.1680/geot.9.p.014
Chang, I., Im, J., Prasidhi, A.K., and Cho, G.C., 2015. Effects of xanthan gum biopolymer on soil strengthening. Construction and Building Materials, 74, pp. 65–72. https://doi.org/10.1016/j.conbuildmat.2014.10.026
Chen, C., Wu, L., Perdjon, M., Huang, X., and Peng, Y., 2019. The drying effect on xanthan gum biopolymer treated sandy soil shear strength. Construction and Building Materials, 197, pp. 271–279. https://doi.org/10.1016/j.conbuildmat.2018.11.120
Debnath, P., and Dey, A.K., 2017. Bearing capacity of reinforced and unreinforced sand beds over stone columns in soft clay. Geosynthetics International, 24(6), pp. 575–589. https://doi.org/10.1680/jgein.17.00024
Dentz, M., Hidalgo, J.J. and Lester, D., 2023. Mixing in porous media: Concepts and approaches across scales. Transport in Porous Media, 146, pp. 5–53. https://doi.org/10.1007/s11242-022-01852-x
Díaz, E., Salamanca-Medina, E.L., and Tomás, R., 2024. Assessment of compressive strength of jet grouting by machine learning. Journal of Rock Mechanics and Geotechnical Engineering, 16(1), pp. 102–111. https://doi.org/10.1016/j.jrmge.2023.03.008
Dutta, R.K., Khatri, V., Sharma, A., and Gayathri, V., 2025. Performance of square footing resting on clay reinforced with granular columns. Transportation Infrastructure Geotechnology, 12(6), Article 189. https://doi.org/10.1007/s40515-025-00640-6
Fattah, M.Y., Shlash, K.T., and Al-Waily, M.J.M., 2011. Stress concentration ratio of model stone columns in soft clays. Geotechnical Testing Journal, 34(1), pp. 50–60. https://doi.org/10.1520/gtj103060
Foye, K.C., Basu, P., and Prezzi, M., 2008. Immediate settlement of shallow foundations bearing on clay. International Journal of Geomechanics, 8(5), pp. 300–310. https://doi.org/10.1061/(ASCE)1532-3641(2008)8:5(300)
Hegde, A., and Sitharam, T.G., 2013. Experimental and numerical studies on footings supported on geocell reinforced sand and clay beds. International Journal of Geotechnical Engineering, 7(4), pp. 346–354. https://doi.org/10.1179/1938636213Z.00000000043
Hughes, J.M.O., and Withers, N.J., 1974. Reinforcing of soft cohesive soils with stone columns. Ground Engineering, 7(3), pp. 42–49.
Inazumi, S., and Shakya, S., 2024. A comprehensive review of sustainable assessment and innovation
in jet grouting technologies. Sustainability, 16(10), Article 4113. https://doi.org/10.3390/su16104113
Jang, J., and Jia, P., 2020. A review of the application of biopolymers on geotechnical engineering and the strengthening mechanisms between typical biopolymers and soils. Advances in Materials Science and Engineering, 2020, Article 1465709. https://doi.org/10.1155/2020/1465709
Jayarajan, J., and Karpurapu, R., 2021. Bearing capacity and settlement response of ordinary and geosynthetic encased granular columns in soft clay soils: analysis and design charts. Indian Geotechnical Journal, 51(2), pp. 237–253. https://doi.org/10.1007/s40098-020-00457-9
Killeen, M.M., and McCabe, B.A., 2014. Settlement performance of pad footings on soft clay supported by stone columns: a numerical study. Soils and Foundations, 54(4), pp. 760–776. https://doi.org/10.1016/j.sandf.2014.06.011
Kitazume, M., and Terashi, M., 2013. The Deep Mixing Method. London: CRC Press. https://doi.org/10.1201/b13873
Kravchenko, E., Lu, W., Sauerwein, M., and Wong, A.H.K., 2024. Life cycle assessment of waste materials in deep cement mixing for land reclamation in Hong Kong. Environmental Impact Assessment Review, 105, Article 107398. https://doi.org/10.1016/j.eiar.2023.107398
Lee, M., Kwon, Y.-M., Park, D.-Y., Chang, I., and Cho, G.-C., 2022. Durability and strength degradation of xanthan gum based biopolymer treated soil subjected to severe weathering cycles. Scientific Reports, 12, Article 19453. https://doi.org/10.1038/s41598-022-23823-4
Lopez, M., and Quevedo, R., 2022. Modeling of settlement and bearing capacity of shallow foundations in overconsolidated clays. Journal of GeoEngineering, 17(1), Article 1. https://doi.org/10.6310/jog.202203_17(1).1
Mach, A., and Szczygielski, M., 2024. Carbon footprint analysis throughout the life cycle of the continuous deep mixing method (CDMM) technology. Energies, 17(13), Article 3294. https://doi.org/10.3390/en17133294
Mehrannia, N., Nazariafshar, J., and Kalantary, F., 2018. Experimental investigation on the bearing capacity of stone columns with granular blankets. Geotechnical and Geological Engineering, 36(1), pp. 209–222. https://doi.org/10.1007/s10706-017-0317-6
Moghal, A.A.B., and Vydehi, K.V., 2021. State-of-the-art review on efficacy of xanthan gum and guar gum inclusion on the engineering behavior of soils. Innovative Infrastructure Solutions, 6(2), Article 108. https://doi.org/10.1007/s41062-021-00462-8
Mohammed, S.M., 2015. The effect of granular material on behaviour of stone columns in soft clay under embankment. Engineering and Technology Journal, 33(9A), pp. 2212–2219. https://doi.org/10.30684/etj.2015.116242
Ni, J., Hao, G.L., Chen, J.Q., Ma, L., and Geng, X.Y., 2021. The optimisation analysis of sand–clay mixtures stabilised with xanthan gum biopolymers. Sustainability, 13(7), Article 3732. https://doi.org/10.3390/su13073732
Sabermahani, M., and Hajisalimi, A., 2025. Field study on jet grouting columns performance above and below groundwater table in sandy soil. Case Studies in Construction Materials, 23, Article e05105. https://doi.org/10.1016/j.cscm.2025.e05105
Sakleshpur, V.A., Prezzi, M., and Salgado, R., 2018. Ground engineering using prefabricated vertical drains: a review. Geotechnical Engineering Journal of the SEAGS & AGSSEA, 49(1), pp. 45–64. https://doi.org/10.14456/seagj.2018.54
Staubach, P., Macháček, J., Bienen, B., and Wichtmann, T., 2022. Long-term response of piles to cyclic lateral loading following vibratory and impact driving in water-saturated sand. Journal of Geotechnical and Geoenvironmental Engineering, 148(11), Article 04022097. https://doi.org/10.1061/(ASCE)GT.1943-5606.0002906
Stuedlein, A.W., and Holtz, R.D., 2013. Bearing capacity of spread footings on aggregate pier reinforced clay. Journal of Geotechnical and Geoenvironmental Engineering, 139(1), pp. 49–58. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000748
Wu, Y., Zhang, Y., Qiu, J., Li, Y., and Xia, S., 2025. pH and hardness of cement-stabilized soil leachate under the influence of multiple factors. Advances in Cement Research, 37(12), pp. 645–653. https://doi.org/10.1680/jadcr.24.00140
Xin, Y., Ding, X., Zhao, J., Wang, H., and Jiang, C., 2025. A study on the response of coral sand foundations with different particle gradations reinforced using a vibroflotation method. Journal of Marine Science and Engineering, 13(4), Article 666. https://doi.org/10.3390/jmse13040666
Zhao, K., and Wong, L.N.Y., 2025. A review of cement-soil in engineering geological applications: mixing mechanisms, mechanical behavior, and constitutive models. Bulletin of Engineering Geology and the Environment, 84(12), Article 637. https://doi.org/10.1007/s10064-025-04659-4