Abstract

All available models of soil shrinkage curves, despite their essential differences, are based on fitting the model parameters. We try to construct a model that enables one to predict the shrinkage curve based on physical parameters, that is, parameters that can be measured or calculated without fitting, independently of an experimental shrinkage curve. Such a model is constructed for real aggregates of clay soils (i.e., soils with clay content approximately > 40% by weight). The intra-aggregate matrix is considered to be a clay matrix that embraces silt and sand grains. An available microstructure-based model of the clay matrix shrinkage curve is used. For data analysis we derive an estimate for the liquid limit of the intra-aggregate matrix. We compare predicted and observed shrinkage curves using available data on aggregates of 31 different swelling soils that are mostly clay soils. As expected the generalized model works for clay soil aggregates with clay content approximately >40% (21 of 31 soils under study). The obtained results of the clay soil aggregates are a prerequisite of the next step relating to the shrinkage modeling of an aggregated soil without fitting.

Keywords: Modeling without fitting; shrinkage; aggregates; clay microstructure.