Morphology-resolved stress contributions in sheared wet granular materials
Ahmad Awdi1, Camille Chateau1, Coumba Niang1
1CNRS, Institut Polytechnique de Paris, Université Gustave Eiffel, Laboratoire NAVIER, ENPC, 77420 Champs-sur-Marne, France.
Physical Review. E
|June 19, 2026
Summary
This study reveals how liquid distribution in wet granular materials affects their strength. Simple liquid bridges dominate capillary pressure, influencing macroscopic friction and material behavior.
Area of Science:
- Geophysics
- Materials Science
- Fluid Dynamics
Background:
- Understanding the mechanical behavior of unsaturated wet granular materials is crucial for various engineering applications.
- The role of liquid bridges and their morphology in granular material rheology remains incompletely understood.
Purpose of the Study:
- To investigate the micro-scale mechanisms governing capillary stresses in wet granular materials.
- To establish a predictive link between liquid morphology and macroscopic rheological properties.
Main Methods:
- Utilized three-dimensional x-ray microtomography combined with rheometric measurements.
- Developed automated classification for liquid domains (bridges, clusters) and tracked their spatial organization.
- Integrated morphology-resolved capillary pressure into an effective-stress framework.
Main Results:
- Demonstrated shear localization's impact on liquid redistribution, with simple bridges uniformly distributed and complex clusters accumulating in shear zones.
- Showed that two-grain capillary bridges contribute ~85% to capillary pressure at a specific liquid content.
- Validated the effective-stress framework's ability to reproduce macroscopic friction without adjustable parameters.
Conclusions:
- Liquid morphology significantly influences the rheology of wet granular materials.
- A micro-macro link between liquid structure and bulk mechanical response was established.
- The findings provide a predictive model for granular material behavior under varying liquid content.
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