Evaluation of Uniformity of Soil Specimens Prepared in Large Tanks by Slurry Consolidation

Abstract

This paper evaluates the degree of uniformity achieved in clay beds prepared for model tests using slurry consolidation method. Clay Specimens were prepared in a cylindrical tank split into five horizontal rings of equal height. This set-up facilitated the sampling of clay for quality checks viz., oedometer tests, gradation analyses, vane shear strength and water content determination in horizontal and vertical directions throughout the specimen. The results from the study show that while the spatial variation of water contents conforms to the acceptance criterion, the same is not true for that of undrained shear strength which is the main parameter of interest for model tests. It is proposed, therefore, to make the acceptance criterion for water content stricter by the factor bs, which is the characteristic of the soil type, depicting slope of the linear function of water content, w, versus undrained shear strength, su, on log–log scale. Oedometer tests showed the reduction of consolidation pressure with depth, which indicates the loss of applied pressure while being transmitted to the lower layers. Gradation analyses suggested no particle segregation in the consolidated specimen. The relation between water content and consolidation pressure was utilised to plot pressure distribution contours throughout the specimen. The uniformity in the specimen was also compared with that prepared through centrifuge consolidation.