Mathematical model of electro-osmotic consolidation for soft ground improvement

Abstract

Electro-osmotic consolidation is an attractive, soft ground improvement technique. In this paper a theoretical model is proposed for electro-osmotic consolidation by coupling the seepage field, electric field, and the stress and strain field. The soil mass deformation, pore-water pressure and the electrical voltage are the basic variables in the governing equations. A three-dimensional numerical model based on the finite-element method was developed to simulate the electro-osmotic consolidation process, predicting the tempo-spatial variation of soil mass displacement. The numerical model is compared with previous analytical solutions. Three common electrode installation patterns are illustrated and analysed with the numerical model, and the results indicate that the triangular pattern can achieve the largest average surface settlement and the smallest differential settlement. The effect of the penetrating depth of the electrodes on the ground settlement is also investigated. An engineering field application is simulated to validate the developed numerical formulation.

Analytical Solution for Electroosmotic Consolidation Considering Nonlinear Variation of Soil Parameters

“…Both the laboratory and field measurements indicated that these soil parameters encountered nonlinear variations during electroosmotic consolidation (Bjerrum et al 1967;Casagrande 1983;Burnotte et al 2004;Hu et al 2012;Zhou et al 2013;Yuan and Hicks 2013;Hu and Wu 2014;Wu and Hu 2014). Such variations would inevitably affect the development of porewater pressure and surface settlement.…”

Electro-osmotic consolidation of soil with variable compressibility, hydraulic conductivity and electro-osmosis conductivity

“…In fact, the flow of pore water from anode to cathode during electro-osmosis causes the decrease in water content and void ratio of the treated soil, and leads to non-linear variations in soil properties such as compressibility, hydraulic conductivity and electro-osmosis conductivity [1,4,5,7,13,[23][24][25][26][27][28]. Such variations would inevitably affect the development of pore water pressure during electro-osmotic consolidation, and the predictions from the existing analytical solutions with constant soil properties would be inaccurate.…”

Numerical analysis of electro-osmosis consolidation: a case study

“…Esrig (1968) first proposed an analytical solution to calculate the excess pore water pressure in a one-dimensional uniform electric field. Based on Esrig's equations, many researchers have since presented analytical and numerical solutions for electro-osmosis consolidation (Lewis & Garner, 1972;Wan & Mitchell, 1976;Shang, 1998;Rittirong & Shang, 2008;Tamagnini et al, 2010;Yuan et al, 2012Jeyakanthan & Gnanendran, 2013;Zhou et al, 2013;Hu & Wu, 2014;.…”

“…analysed the electro-osmosis test carried out by Micic et al (2003), accounting for the three-dimensional (3D) geometry and boundary conditions as well as elasto-plastic material behaviour. Hu & Wu (2014) performed a numerical simulation of the field test conducted by Bjerrum et al (1967); two-dimensional (2D) and 3D geometries were both accounted for, based on an elastic constitutive relationship and a single representative section between one anode and one cathode. The same field test was analysed by , who considered large strain and elasto-plastic constitutive behaviour in a 2D simulation of a single representative section of the full test.…”