Evaluation of Consolidation Behavior under Horizontal Drainage Condition Using Digital Image Analysis

Analytical solutions to predict the consolidation behavior of soft soils with vertical drains generally assume that soils are compressed only in the vertical direction. During consolidation, however, soils deform not only vertically but also radially in cases of radial drainage conditions, even though it is assumed that overall radial deformation is not occurred. Radial deformation may influence the consolidation response and also results in unexpected non-uniform soil conditions during and after consolidation. A new consolidation apparatus, which enables the deformation of a specimen to be visually observed, and the total vertical stress as well as the pore water pressure to be measured at several locations, was developed. Consolidation test using the developed apparatus was performed for reconstituted kaolinite specimen under horizontal drainage condition. Digital image analysis technique was adopted to analyze the consolidation deformation of the specimen. Horizontal deformation as well as vertical deformation developed during the consolidation process were obtained and the local consolidation behaviors were evaluated. The results show that consolidation behaviors are distinctive according to the distance from the drainage surface and the ground surface.