On the use of dimensional analysis to predict swelling strain

Soil swelling is a complex phenomenon, the magnitude of which is not trivial to predict. It is affected by many parameters including the initial hydration state of the soil, its initial level of compaction (or density) and the level of confinement. It is hereby proposed to extend a preliminary research which dealt with using the dimensional analysis to predict the swelling strain of different soils. Dimensional analysis is a common technique in Fluid Mechanics but it is not used that often in Geotechnical Engineering despite its versatility. The present work presents the derivation of dimensionless numbers for three swelling configurations: under oedometric conditions (one dimensional) until full saturation, under isotropic confinement (three dimensional) until full saturation and one dimensional with controlled suction. Some extensive experimental testing has been conducted in order to provide a database for validation of the first two dimensionless models. Data from the literature have been used to validate the approach on partial swelling under controlled suction. Results of calibration–prediction exercises are provided, which suggest that dimensional analysis is a simple, efficient and accurate tool to predict swelling strain, at least for the three configurations tested. The paper also provides a discussion on some limitations of the model and on the minimum number of tests required to calibrate the models.