Open Access

ARTICLE

Experimental Investigation of Seepage-Induced Rheological Deformation in Mucky Soft Soil Containing Medium-Fine Sand

Longbin Lin¹, Hua Hu^2,*

1 School of Civil Engineering, Xiamen University Tan Kah Kee College, Zhangzhou, China
2 School of Architecture and Civil Engineering, Xiamen University, Xiamen, China

* Corresponding Author: Hua Hu. Email:

Fluid Dynamics & Materials Processing 2026, 22(7), 7 https://doi.org/10.32604/fdmp.2026.085657

Received 19 May 2026; Accepted 15 July 2026; Issue published 31 July 2026

Abstract

Seepage-induced rheological deformation represents a critical factor governing the long-term stability of coastal soft-soil excavations subjected to intense rainfall infiltration and groundwater fluctuations. This study elucidates the individual and interactive effects of seepage pressure and seepage duration on the time-dependent deformation behavior of undisturbed mucky soft soil containing medium-fine sand, collected from a deep foundation pit. A comprehensive experimental campaign based on triaxial seepage-shear rheological testing for a confining pressure of 180 kPa is presented, encompassing sixteen combinations of seepage pressure and duration together with a directly measured zero-seepage reference condition. Three replicate specimens are examined for each testing scenario. The results demonstrate that seepage significantly accelerates rheological deformation, with axial strain exhibiting a pronounced nonlinear dependence on both hydraulic loading intensity and exposure duration. Under the most adverse seepage condition considered, namely a seepage pressure of 70 kPa maintained for 120 min, the mean axial strains reach 3.63 ± 0.25% and 10.81 ± 0.71% at deviatoric stresses of 300 and 600 kPa, respectively, compared with only 1.34 ± 0.09% and 4.77 ± 0.20% under zero-seepage conditions. Two-way analysis of variance confirms that seepage pressure, seepage duration, and their combined interaction exert statistically significant control over the rheological response. To further characterize this coupled hydraulic-mechanical behavior, an empirical power-law response-surface model is established to describe the dependence of deformation on seepage conditions. The proposed model exhibits strong predictive capability within the investigated range, yielding coefficients of determination of 0.9488 and 0.8579 and leave-one-condition-out cross-validation Q² values of 0.9208 and 0.7371 at deviatoric stresses of 300 and 600 kPa, respectively. The framework is specifically applicable to stable pre-failure deformation regimes and should not be extended to conditions approaching failure, such as those corresponding to a deviatoric stress of 900 kPa.

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Keywords

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