Shrinkage anisotropy characteristics from soil structure and initial sample/layer size

TL;DR

This paper develops a physical model to predict soil shrinkage anisotropy based on sample size, layer thickness, and soil structure, providing new insights into how drying affects soil deformation.

Contribution

It introduces a novel approach linking soil shrinkage anisotropy to sample size, layer thickness, and soil structure through a new size ratio framework.

Findings

Predicted shrinkage anisotropy varies with sample size and soil structure.

Established relationships between shrinkage curves and physical soil parameters.

Provided illustrative estimates for different soil samples and sizes.

Abstract

The objective of this work is a physical prediction of such soil shrinkage anisotropy characteristics as variation with drying of (i) different sample/layer sizes and (ii) the shrinkage geometry factor. With that, a new presentation of the shrinkage anisotropy concept is suggested through the sample/layer size ratios. The work objective is reached in two steps. First, the relations are derived between the indicated soil shrinkage anisotropy characteristics and three different shrinkage curves of a soil relating to: small samples (without cracking at shrinkage), sufficiently large samples (with internal cracking), and layers of similar thickness. Then, the results of a recent work with respect to the physical prediction of the three shrinkage curves are used. These results connect the shrinkage curves with the initial sample size/layer thickness as well as characteristics of soil texture and structure (both inter- and intra-aggregate) as physical parameters. The parameters determining the reference shrinkage curve (relating to the small samples) and initial sample size/layer thickness are needed for the prediction of the above soil shrinkage anisotropy characteristics. Using the available data on two soils and samples of two essentially different sizes, illustrative estimates of the relative sample sizes, new characteristic of the shrinkage anisotropy, and shrinkage geometry factor are given as the physically predicted values.