<p>Clayey soils have low strength, high compressibility, and large reductions in their bearing capacity after exposure to moisture, thus not being appropriate for engineering applications such as pavements and foundations. The conventional methods are expensive and damages the environment. Therefore, sustainable and eco-friendly alternatives are needed to mitigate the problem. The present study aims to investigate the potential of bio-mediated stabilization using bacterial solution (BS) and guar gum (GG) biopolymer to improve the mechanical properties of clayey soils. To assess the efficiency of the stabilization process, a wide range of experimental investigations was conducted using triaxial compression tests and California Bearing Ratio (CBR) tests under different curing conditions. Various percentages of bacterial solution (0.5%, 1.0%, and 1.5%) and guar gum (0.5%, 1.0%, 1.5%, and 2.5%) were used to assess their individual and synergistic effects on the shear strength properties of the soils. The results of the triaxial test showed that the deviatoric stress and shear strength parameters of the soils treated using the bacterial solution and guar gum showed a significant improvement when compared to the untreated soil. The results showed that the mixture containing 1.0 BS and 0.5% GG revealed the highest improvement, where the maximum deviatoric stress values of 511 kPa, 688 kPa, and 861 kPa were achieved at different confining pressures of 50 kPa, 100 kPa, and 150 kPa, respectively. For the untreated soil, the CBR values of 2.71% and 0.76% were obtained in the unsoaked and soaked test conditions, respectively. This revealed poor subgrade stability. In contrast, the results obtained from the combined stabilization technique showed remarkable improvement in the CBR values. For the optimum mixture of 1.0 BS + 0.5% GG, the highest unsoaked CBR value of 16.24% and soaked CBR value of 14.22% were obtained at the end of 7 days of curing, which revealed approximately six-fold and eighteen-fold improvement over the CBR values of the untreated soils. The application of bacterial solution and guar gum biopolymer results in an improvement in the shear strength behaviour and load-carrying capacity of the clayey soil. The improvement in the soil is attributed to the formation of calcium carbonate bonds as a result of microbial action and the formation of a biopolymer network revelled in microstructural analysis, which increases the soil strength.</p>

Bio- mediated stabilization of clayey soil

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2026年6月26日

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Nisha K. Singh,
Ajanta Kalita

摘要

Clayey soils have low strength, high compressibility, and large reductions in their bearing capacity after exposure to moisture, thus not being appropriate for engineering applications such as pavements and foundations. The conventional methods are expensive and damages the environment. Therefore, sustainable and eco-friendly alternatives are needed to mitigate the problem. The present study aims to investigate the potential of bio-mediated stabilization using bacterial solution (BS) and guar gum (GG) biopolymer to improve the mechanical properties of clayey soils. To assess the efficiency of the stabilization process, a wide range of experimental investigations was conducted using triaxial compression tests and California Bearing Ratio (CBR) tests under different curing conditions. Various percentages of bacterial solution (0.5%, 1.0%, and 1.5%) and guar gum (0.5%, 1.0%, 1.5%, and 2.5%) were used to assess their individual and synergistic effects on the shear strength properties of the soils. The results of the triaxial test showed that the deviatoric stress and shear strength parameters of the soils treated using the bacterial solution and guar gum showed a significant improvement when compared to the untreated soil. The results showed that the mixture containing 1.0 BS and 0.5% GG revealed the highest improvement, where the maximum deviatoric stress values of 511 kPa, 688 kPa, and 861 kPa were achieved at different confining pressures of 50 kPa, 100 kPa, and 150 kPa, respectively. For the untreated soil, the CBR values of 2.71% and 0.76% were obtained in the unsoaked and soaked test conditions, respectively. This revealed poor subgrade stability. In contrast, the results obtained from the combined stabilization technique showed remarkable improvement in the CBR values. For the optimum mixture of 1.0 BS + 0.5% GG, the highest unsoaked CBR value of 16.24% and soaked CBR value of 14.22% were obtained at the end of 7 days of curing, which revealed approximately six-fold and eighteen-fold improvement over the CBR values of the untreated soils. The application of bacterial solution and guar gum biopolymer results in an improvement in the shear strength behaviour and load-carrying capacity of the clayey soil. The improvement in the soil is attributed to the formation of calcium carbonate bonds as a result of microbial action and the formation of a biopolymer network revelled in microstructural analysis, which increases the soil strength.