The influence of changes in water content on the electrical resistivity of a natural unsaturated loess

TL;DR

This study develops a new electrical resistivity probe to monitor local water content changes in unsaturated loess, analyzing the relationship between resistivity and saturation through experiments and theoretical models.

Contribution

A novel resistivity probe was designed and tested to measure local water content variations in unsaturated loess, integrating experimental data with theoretical analysis.

Findings

Resistivity increases with decreasing water saturation in loess.

Theoretical models effectively describe resistivity-saturation relationship.

Water retention properties of loess are discussed based on resistivity data.

Abstract

Non-destructive methods of measuring water content in soils have been extensively developed in the last decades, especially in soil science. Among these methods, the measurements based on the electrical resistivity are simple and reliable thanks to the clear relationship between the water content and the electrical resistivity of soils. In this work, a new electrical resistivity probe was developed to monitor the change in local water content in the triaxial apparatus. The probe is composed of two-pair of electrodes, and an electrical current is induced through the soil at the vicinity of the contact between the probe and the specimen. Some experimental data on the changes in resistivity with the degree of saturation were obtained in specimens of a natural unsaturated loess from Northern France. Two theoretical models of resistivity were also used to analyze the obtained data. Results are finally discussed with respect to the loess's water retention properties.