Laboratory Measurement of Porosity and Formation Factor in Granular Media Using Conductivity-Type Concentration Meters (CCM)
Laboratory Measurement of Porosity and Formation Factor in Granular Media Using Conductivity-Type Concentration Meters (CCM)
In geotechnical laboratory practice, determination of the density of a granular specimen throughout the course of testing is a key concern. The density or the packing of the granular media can be translated into the stiffness of the material which may increase or decrease depending on the type of the experiment, applied loading, boundary condition, and many other contributing factors. While there are some wave speed dependent measurement techniques available, the equipment required or the difficulty in examining the acquired results limits the applicability and practicality of such techniques. For example, bender element testing requires reasonably complicated electronics interfaces capable of very high sampling rates. Moreover, other bespoke techniques which rely on the wave propagation speed are plagued by the background noise generated in the tests and their use is often limited to geotechnical centrifuge domain. Beyond these inherent shortcomings associated with the wave propagation measurement techniques, the conversion from stiffness to the density of the material also requires correlations which might further limit their use for density measurements. Although the electrical conductivity/resistivity measurements are widely recognized as a means to infer soil moisture content or salinity, the electrical resistivity of the granular media could also be used as an indicator of the packing density. This contribution shares a novel technique of density measurement utilizing electrical conductivity. The contribution elaborates on the working principle of the sensors and highlights results of a series of calibration tests conducted at Deltares.
Cihan Cengiz
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Session 1: New facilities, new equipment, and measuring techniques
https://doi.org/10.53243/ICPMG2026-25