The role of free‐strain assumption in axisymmetric electro‐osmosis‐enhanced preloading consolidation of unsaturated soil

Abstract

AbstractThe axisymmetric, equal‐strain consolidation theory of soil is widely employed in engineering due to the user‐friendliness of its solution. However, the radially averaged excess pore pressure (EPP) is unable to reveal the coupling effect of the radial electric field when the soil is consolidated by electro‐osmotic and surcharge preloading. In this paper, the axisymmetric consolidation analytical models with free strain and equal strain assumptions are developed to investigate the importance of the free strain assumption in the consolidation of unsaturated soil by electro‐osmosis‐aided preloading. The finite Hankel transform, decoupling technique, and Laplace transform are then utilised to derive the semi‐analytical solutions. Finally, the comparison of EPP, surface settlement, and average degree of consolidation under the two assumptions reveals that the free‐strain solution accurately shows the distribution of EPP at any point in the soils and the development of surface settlement at different radii, thus helping to analyse the electro‐osmotic consolidation characteristics. Moreover, it was discovered that electro‐osmosis combined with preloading allows for a more uniform consolidation of unsaturated soil. The difference in the average degree of consolidation under both assumptions is insignificant, while the installation distance of the cathode and anode vertical wells has a significant effect.