Analytical Solution for Electroosmotic Consolidation Considering Nonlinear Variation of Soil Parameters

Abstract

Electroosmotic consolidation can be used as an efficient technique for soft soil improvement. Considering the limitation in previous theories that soil parameters keep constant during electroosmotic consolidation, the nonlinear relationships between soil compressibility, hydraulic and electroosmosis conductivities, and void ratio are incorporated in a one-dimensional model in the present study. The analytical solutions for the ultimate excess pore-water pressure and surface settlement are derived. A comparison between the proposed analytical solutions and traditional theory indicates that the nonlinear variation of hydraulic conductivity results in a larger ultimate excess pore-water pressure, whereas the nonlinear variation of electroosmosis conductivity leads to a smaller one. The effects are more significant for soils with higher compressibility. The nonlinear variation of soil compressibility exhibits remarkable impact on the development of excess pore-water pressure when the nonlinear variations of hydraulic and electroosmosis conductivities are considered. Compared with the ultimate excess pore-water pressure, the impact of nonlinear variations of soil parameters on the ultimate surface settlement is less significant.

Development and Verification of a New Simplified Method for Calculating Settlement of a Thick Soil Layer with Nonlinear Compressibility and Creep

“…In Terzaghi's theory, the stress-strain relationship of soils is linear, resulting that soil compressibility is a constant in the vertical direction. However, the compressibility of soft soils is closely related to the initial and final effective stresses along the depth (Davis and Raymond 1965;Gibson et al 1967;Poskitt 1969;Hawley and Borin 1973;Abbasi et al 2007;Abuel-Naga and Pender 2012;Abuel-Naga et al 2015;Wu et al 2016). Due to the stress history and geological process, the initial effective stress and pre-consolidation pressure normally increase with depth in the field, thus, the soil compressibility varies with depth of the soft soil layer nonlinearly when the ground is subjected to an external loading (Craig 2004).…”

“…Subsequently, researchers such as Menéndez et al (2010), Abuel-Naga and Pender (2012), Brandenberg (2016), Wu et al (2016), Pu et al (2018aPu et al ( , 2018b, Li et al (2018), Liu et al (2018) focus on this challenging area and make meaningful achievements. Therefore, the variable compressibility of soft soils is necessary to be considered in settlement calculation of soft soil layers, especially for thick soil layers.…”

Model Tests of Soil Reinforcement Inside the Bucket Foundation with Vacuum Electroosmosis Method

“…Electroosmosis improves the permeability coefficient of the soil and reduces the amount of weakly absorbed water regardless of grain assize [32]. In recent years, electroosmotic strengthening of soil has been widely studied [33][34][35][36]. This study employed a series of model tests to quantitatively analyze foundation settlement, pore water pressure inside the soil, soil moisture content before and after reinforcement, and undrained shear strength of the soil.…”

Derivation of Universal Curves for Nonlinear Soil Consolidation with Potential Constitutive Dependences

“…Geng et al [4] and Lu et al [5] studied nonlinear soil consolidation problems, the first under cycling loadings, and the second under time-variable loadings and vertical drains, using logarithmic type constitutive relations for the main variables of the problem (void ratio, effective stress and hydraulic conductivity), obtaining that both the initial stress state and the ratio of the coefficients of the constitutive relations are the most influential parameters that govern the consolidation process. Other references to nonlinear consolidation are the papers of Wu et al [6] and Brandenberg [7], which also handle logarithmic dependences with the void ratio. The first author presents an analytical solution for the electroosmotic consolidation with no allusion to the dimensionless groups that rule the problem, while the second approximates the secondary consolidation.…”