Resistivity characteristics during horizontal-layered electrolysis desaturation of calcareous sand

• Published in: Engineering geology Vol. 279; p. 105899
• Main Authors: Zhang, Zhe, Chen, Yumin, Liu, Hanlong, Zhou, Yunfeng, Zhou, Xiaozhi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20-12-2020
• Subjects: Calcareous sand; Degree of saturation; Electrolysis desaturation method; Resistivity; Temperature; X-CT; Electrolysis desaturation method; Temperature; Degree of saturation; Calcareous sand; Resistivity; X-CT
• ISSN: 0013-7952; 1872-6917
• DOI: 10.1016/j.enggeo.2020.105899

The electrolysis desaturation method is a novel method for treating liquefiable sand. However, the mechanisms of the electrolysis desaturation method are unclear. X-ray computed tomography (X-CT) tests were conducted calcareous sand to investigate the behavior of the gas bubbles inside the sample during the electrolysis process. The temperature inside the calcareous sand and the resistivity of the sand between the electrodes were monitored during desaturation. The results show that five distinct stages of resistivity variation in sand can be identified over the whole process of electrolysis. All the stages were controlled by the temperature and the gas bubbles generated during electrolysis. The bubbles generated during electrolysis are formed and stored in sand voids by two modes: capillary invasion and the formation of small bubbles, resulting in a slight increase in the resistivity of the sand; or displacement of the sand particles and the formation of large bubbles, resulting in a significant increase in the resistivity of the sand. The cathode has a significant effect on the behavior of the bubbles, and the saturation around the cathode is always lower than that in other zones throughout the process of electrolysis. Compared with McNeill's function, a cubic function relationship is more suitable for describing the relationship between the resistivity and saturation of calcareous sand during electrolysis. The end of stage II of the resistivity variation, that is, when the resistivity of the sand stops declining, is the right time to end the electrolysis. This study improves our understanding of the physical processes of electrolysis desaturation and provides insights into the potential application of electrolysis desaturation in the prevention and treatment of sand liquefaction.
•The physical processes of electrolysis desaturation are presented.•Five distinct stages of resistivity variation of sand is identified in the whole process of electrolysis.•The storage of gas bubbles produced by electrolysis in calcareous sand is visualized.•The mechanisms of electrolysis desaturation in horizontal layered calcareous sand are discussed.•Insights are provided for potential applications of electrolysis desaturation.