Physical modelling of cohesive soil inherent variability: consolidation problem

Abstract

Abstract The main goal of this study is to substantiate the heterogeneous soil modelling in the laboratory and to examine the effect of spatial variability on the soil consolidation properties. For this purpose, several heterogeneous soil physical models are constructed using nine homogeneous soil clusters, which are prepared by mixing variable proportions of kaolin and bentonite at a specific water content equal to the liquid limit of the mixtures. The index properties of different homogeneous kaolin–bentonite clusters are utilized to model the spatial variability of the heterogeneous soil models using the random field generation approach. The physical model contains different discrete cells where the variability is controlled by the specific realizations of a random field. The number of these realizations in the heterogeneous model is augmented by varying the liquid limit of the mixtures. The constructed physical models are then subjected to several one-dimensional consolidation stages using the oedometer apparatus and the influence of the heterogeneity of the soil sample on its hydraulic parameters is evaluated. The results show that the higher variability involved in the soil strata, expressed through the larger coefficient of variation and smaller correlation distance, leads to the increase in the hydraulic conductivity and coefficient of consolidation of the heterogeneous soil physical model. It is also revealed that the experimental modelling of soil spatial variability can shed light on the numerical simulation of random field theory presented in several previous studies.

Keywords

• Kaolin–bentonite mixture
• Consolidation
• Heterogeneous physical model
• Hydraulic conductivity
• Coefficient of variation