Abstract
To investigate the effects of freeze-thaw cycles and immersion on the physicochemical properties, deformation characteristics, and state of dispersive clay, laboratory physical, chemical, and compression tests were conducted on dispersive clay, and a compression deformation formula for dispersive clay under freeze-thaw cycles and immersion conditions was proposed based on the test results. The results indicate that after undergoing freeze-thaw cycles and immersion, the sodium and potassium ions in the clay decreased by 91%~95%, and the pH value dropped from 9.24 to 7.47; the particle size (0.075~0.005 mm and <0.005 mm) increased, the liquid limit and specific gravity increased, while the plastic limit remained unchanged; immersion caused the exchange and loss of sodium ions in dispersive clay, and its compressibility was higher than that of non-dispersive clay; freeze-thaw cycles and immersion deteriorated the dispersive clay mass, accelerated the ion loss process, altered the compression curve, and resulted in a significant deepening of the flocculent structure; after approximately 10 h of freeze-thaw cycles and immersion, the dispersive clay exhibited a completely flocculent structure.
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Preamble
Study on the Physicochemical and Compressive Deformation Characteristics of Dispersive Clay Under the Coupling Effect of Freezing-Thawing Cycles and Immersion
Han Xiao¹, He Rui¹, Wang Lixiang²,³
¹Guiyang Engineering Corporation Limited, Guiyang 550081, China
²Huangshan University, Huangshan 245021, China
³Anhui and Huaihe River Institute of Hydraulic Research, Hefei 233000, China
Abstract: This study investigates the effects of freeze-thaw cycles and immersion on the physicochemical properties, deformation characteristics, and state of dispersive clay through laboratory physical, chemical, and compression testing. Based on the experimental results, a compression deformation formula for dispersive clay under freeze-thaw and immersion conditions is proposed. The results demonstrate that after freeze-thaw cycling and immersion, sodium and potassium ions in the clay decreased by 91–95%, while pH declined from 9.24 to 7.47. Particle sizes in the 0.075–0.005 mm and <0.005 mm fractions increased, liquid limit and specific gravity increased, and plastic limit remained unchanged. Immersion caused leaching of exchangeable sodium ions from the dispersive clay, yielding higher compressibility than non-dispersive clay. The combined action of freeze-thaw cycles and immersion deteriorated the clay structure, accelerated ion loss, altered compression curves, and significantly increased the depth of the flocculated structure. After approximately 10 hours of freeze-thaw cycling and immersion, the dispersive clay exhibited a fully flocculated structure.
Keywords: Dispersive clay; Freeze-thaw cycles; Exchangeable sodium; Physicochemical properties; Compressibility