EIT Oedometer : An Advanced Cell to Monitor Spatial and Time Variability in Soil with Electrical and Seismic Measurements

The paper presents an innovative oedometer cell (EIT oedometer), accomplishing for monitoring the spatial and temporal evolution of different physical quantities inside soil samples through seismic and electric non-destructive measurements. The technical solutions implemented to perform correct electrical measurements are reported together with the results of benchmark tests demonstrating the potentialities and the limits of the 3D electrical resistivity tomography in detecting both pre-existing and induced sample heterogeneities. It is shown that resistivity imaging can offer a powerful tool for the investigation of soil heterogeneities not detected by external measurements. The relationship between electrical resistivity and soil properties makes this application potentially useful for monitoring the evolution of transient processes as for instance those related to the diffusion of chemical species in clay soils and associated coupled chemo-mechanical processes, whereas the information gathered by classical oedometer measurements and by seismic waves propagation could be used to explore the associated macroscopic phenomena.

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