Optimizing soil conditioning by foam during EPB shield tunnelling based on surface tension measurement
- Author
- Zhongtian Chen, Chuan He, Adam Bezuijen (UGent) , Yong Fang, Jian Cui and Xiongyu Hu
- Organization
- Abstract
- Foam is the most commonly used chemical additive for soil conditioning in earth pressure balance (EPB) shield tunnelling. Investigating foam generation, stability, and application through surface tension analysis can enhance the efficiency of soil conditioning. This study presents extensive laboratory experiments, including surface tension measurements using the capillary rise and platinum plate methods, foam generation and stability tests based on the mixing method and foam generator, and foam application using slump tests. The results show that the foaming agents used in this study exhibit similar surface tension curves, with a critical micelle concentration (CMC) of approximately 0.1%. The presence of pore water in sand would increase the consumption of foaming agent by increasing the surface tension of foaming agent solutions. The distribution of surfactant molecules and micelles is critical to surface tension measurement, foam generation, and foam stability. In practical shield tunnelling, the concentration of the foaming agent solution should be substantially higher than the CMC, as surfactant density decreases during foam generation when the surface area increases. The capillary rise method, which reflects the surfactant density within the solution, is more suitable for assessing foam performance in shield tunnelling, since surfactants inside the solution are required during foam generation. Moreover, surface tension measured by the capillary rise method shows a linear correlation with the foaming ability of the solution and foam stability, as well as with the foam volume consumed in soil conditioning of sand. Foam exhibits lower stability when mixed with coarse sand in foam sand mixtures.
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Citation
Please use this url to cite or link to this publication: http://hdl.handle.net/1854/LU-01KBMNRSBTBYCYFXBBAY9544A3
- MLA
- Chen, Zhongtian, et al. “Optimizing Soil Conditioning by Foam during EPB Shield Tunnelling Based on Surface Tension Measurement.” TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY, vol. 169, 2026, doi:10.1016/j.tust.2025.107306.
- APA
- Chen, Z., He, C., Bezuijen, A., Fang, Y., Cui, J., & Hu, X. (2026). Optimizing soil conditioning by foam during EPB shield tunnelling based on surface tension measurement. TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY, 169. https://doi.org/10.1016/j.tust.2025.107306
- Chicago author-date
- Chen, Zhongtian, Chuan He, Adam Bezuijen, Yong Fang, Jian Cui, and Xiongyu Hu. 2026. “Optimizing Soil Conditioning by Foam during EPB Shield Tunnelling Based on Surface Tension Measurement.” TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY 169. https://doi.org/10.1016/j.tust.2025.107306.
- Chicago author-date (all authors)
- Chen, Zhongtian, Chuan He, Adam Bezuijen, Yong Fang, Jian Cui, and Xiongyu Hu. 2026. “Optimizing Soil Conditioning by Foam during EPB Shield Tunnelling Based on Surface Tension Measurement.” TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY 169. doi:10.1016/j.tust.2025.107306.
- Vancouver
- 1.Chen Z, He C, Bezuijen A, Fang Y, Cui J, Hu X. Optimizing soil conditioning by foam during EPB shield tunnelling based on surface tension measurement. TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY. 2026;169.
- IEEE
- [1]Z. Chen, C. He, A. Bezuijen, Y. Fang, J. Cui, and X. Hu, “Optimizing soil conditioning by foam during EPB shield tunnelling based on surface tension measurement,” TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY, vol. 169, 2026.
@article{01KBMNRSBTBYCYFXBBAY9544A3,
abstract = {{Foam is the most commonly used chemical additive for soil conditioning in earth pressure balance (EPB) shield tunnelling. Investigating foam generation, stability, and application through surface tension analysis can enhance the efficiency of soil conditioning. This study presents extensive laboratory experiments, including surface tension measurements using the capillary rise and platinum plate methods, foam generation and stability tests based on the mixing method and foam generator, and foam application using slump tests. The results show that the foaming agents used in this study exhibit similar surface tension curves, with a critical micelle concentration (CMC) of approximately 0.1%. The presence of pore water in sand would increase the consumption of foaming agent by increasing the surface tension of foaming agent solutions. The distribution of surfactant molecules and micelles is critical to surface tension measurement, foam generation, and foam stability. In practical shield tunnelling, the concentration of the foaming agent solution should be substantially higher than the CMC, as surfactant density decreases during foam generation when the surface area increases. The capillary rise method, which reflects the surfactant density within the solution, is more suitable for assessing foam performance in shield tunnelling, since surfactants inside the solution are required during foam generation. Moreover, surface tension measured by the capillary rise method shows a linear correlation with the foaming ability of the solution and foam stability, as well as with the foam volume consumed in soil conditioning of sand. Foam exhibits lower stability when mixed with coarse sand in foam sand mixtures.}},
articleno = {{107306}},
author = {{Chen, Zhongtian and He, Chuan and Bezuijen, Adam and Fang, Yong and Cui, Jian and Hu, Xiongyu}},
issn = {{0886-7798}},
journal = {{TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY}},
language = {{eng}},
pages = {{15}},
title = {{Optimizing soil conditioning by foam during EPB shield tunnelling based on surface tension measurement}},
url = {{http://doi.org/10.1016/j.tust.2025.107306}},
volume = {{169}},
year = {{2026}},
}
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