Electroosmotic drainage has been proposed as a method for reducing moisture content and simultaneously increasing shear strength, thereby enhancing the stability of soft clays. Understanding electroosmotic consolidated soil behavior under wet-dry cycles is vital for assessing long-term stability and performance in a changing environment. In this investigation, electroosmosis-treated soft clay specimens were prepared and subjected to different wetting-drying cycles. The experimental results emphasized that in the case of soft clay which has been treated under identical electroosmosis conditions and subsequently subjected to varying numbers of wetting-drying cycles, it was determined that with an increment in the number of wetting-drying cycles, the crack ratio exhibits an increasing trend. However, the extent of the crack ratio exerts a minimal and almost negligible effect on the average moisture content of the soil mass. Specifically, five wetting-drying cycles can induce a pronounced reduction in the coefficient of variation (COV) of the soil moisture content distribution. Moreover, it was observed that a relatively smaller crack ratio is associated with a relatively greater average shear strength. Simultaneously, the corresponding COV will be larger. Conversely, a larger crack ratio gives rise to a smaller average shear strength, and the corresponding COV will be smaller.

Electroosmosis and surcharge preloading represent two effective soil consolidation methodologies. Their combined application has been proven to be effective in shortening the consolidation period and mitigating the degradation of electroosmotic consolidation performance due to crack generation. In this study, an axisymmetric free-strain consolidation analytical model incorporating a continuous drainage top boundary was established. A semi-analytical solution was then derived utilizing Laplace-Hankel transform and boundary condition homogenization. The validity of the proposed solution was confirmed by comparing it with three cases documented in the existing literature. Additionally, a comparison with indoor model box test results demonstrated the rationality of setting the top boundary as a continuous drainage boundary. Parameter analysis revealed several key insights: firstly, under the free strain assumption, the spatiotemporal distribution of excess pore water pressure aptly captured the coupled effects of the radial electric field. Secondly, the combination of electro-osmosis and preloading technology significantly improved consolidation efficiency, with this effect becoming more pronounced as the applied voltage increased. Lastly, the general solution based on the continuous drainage boundary proved to be suitable for addressing the consolidation of soft soils enhanced by vertical drainage, applicable to real foundation consolidation problems with top boundaries exhibiting different permeabilities.

In this study, electro-osmotic consolidation considering smear effect and free strain under cyclic loading was investigated. The analytical solution of radial consolidation of electroosmosis-vacuum-surcharge combined preloading is derived by using the Bessel function and eigenfunction methods. Subsequently, the effectiveness of the proposed method is validated through comparison with existing numerical solutions. Based on the derived solutions, the influence of the smear effect, applied voltage, vacuum pressure, and cyclic loading on soil consolidation characteristics was analyzed. The results showed that the smearing effect slows the rate of consolidation, but the final average consolidation and negative excess pore water pressure are enhanced. Compared with only cyclic loading, the combined effect of electroosmosis, vacuum, and surcharge preloading enables the soil to achieve higher strength and consolidation. When the effect of electroosmosis alone on reinforcing low-permeability soils is not significant, the combination of electroosmosis with vacuum preloading helps enhance the soil reinforcement effect.

The electrical conductivity of soil is closely associated with various physical properties of the soil, and accurately establishing the interrelationship between them has long been a critical challenge limiting its widespread application. Traditional approaches in geotechnical engineering have relied on specific conduction mechanisms and simplifying assumptions to construct theoretical models for electrical conductivity. This paper adopts a different approach by using machine learning methods to predict the electrical conductivity of clay materials. A reliable dataset was generated using the quartet structure generation set to create random clay microstructures and calculate their electrical conductivity. Based on this dataset, machine learning methods such as least squares support vector machine and backpropagation neural networks outperform theoretical models in terms of prediction accuracy and resistance to interference, with a coefficient of determination (R2) exceeding 0.995 when unaffected by disturbances. The computation of Shapley values for input features aids in explicating the machine learning model. The results reveal that saturation is a key feature in predicting electrical conductivity, while porosity and constrained diameter are relatively less important. Finally, an already trained model is applied to the one-dimensional electroosmosis-surcharge preloading consolidation theory. The results of the calculations demonstrate that neglecting changes in soil electrical conductivity during electroosmosis can lead to an overestimation of the absolute values of anode excess pore water pressure and soil settlement.

The combining of electroosmotic, vacuum, and surcharge preloading is an emerging technique for soft foundation treatment. Considering smear effects and free strain, an analytical solution for the radial consolidation of combined electroosmotic, vacuum, and surcharge preloading was derived based on the characteristic function method and Bessel function. The correctness of the proposed solution was verified by comparing with existing solutions and numerical results. On this basis, the influence of smear effects, vacuum pressure, surcharge load, and applied voltage on the consolidation characteristics of soil was further analyzed. The results showed that when the electroosmosis permeability coefficient of the undisturbed zone was greater than that of the smear zone, the excess pore-water pressure at the interface between the smear zone and the undisturbed zone increased in the early stage of consolidation owing to the electroosmotic effect. Vacuum pressure had a great influence on soil consolidation in the smear zone, while applied voltage had a great influence on the consolidation of soil in the undisturbed zone.

During the construction of pile foundations, the generation of vast amounts of engineering slurry, with poor geotechnical mechanical properties, requires expeditious treatment. In this paper, composite flocculants, consisting of anionic polyacrylamide (APAM), slaked lime (Ca (OH)2), and poly aluminum chloride (PAC) in varying proportions, were used to pretreat high water content (150%) engineering slurries. Afterwards, electroosmosissolidification treatment tests were carried out on the pretreated slurries to determine the influence of composite flocculant pretreatment on the efficacy of electro-osmosis treatment. The results indicate that the addition of a composite flocculant, APAM-PAC-Ca (OH)2, allows for the formation of flocs with structural pores within the slurry, which creates more favorable conditions for electroosmotic drainage treatment. After electroosmosis, the composite flocculant treated slurry led to lower average corrosion coefficients and presented with more uniform changes to soil moisture and 50% higher undrained soil shear strengths compared to samples treated with a single flocculant. The incorporation of Ca (OH)2 in the composite flocculant was shown to effectively decrease the extent of anode corrosion. Additionally, scanning electron microscope (SEM) imaging of the composite flocculant-treated and electroosmosis-treated slurries show the presence of CSH, CAH, AFt, polymer network structures and other products in the solidified slurry. The filling of the pores demonstrated the strengthening of the soil, meeting the requirements of external transportation and reuse.