Acoustic Emission as an indicator of sand deformation in drained triaxial tests
Acoustic Emission as an indicator of sand deformation in drained triaxial tests
AE is a non-destructive method that captures high-frequency waves from micromechanical events in soils, offering insight into deformation onset and proximity to failure. This study evaluates AE as an early-warning indicator using drained triaxial tests on Ottawa sand at two relative densities, 40% and 85%. A conventional triaxial apparatus instrumented with resonant sensors embedded in the end caps recorded acoustic activity during creep and shear. AE intensity was quantified by signal strength (SS) and compared with deviatoric stress, axial strain, and volumetric strain. During creep, the SS rate was near zero, then increased immediately at the onset of shearing, demonstrating sensitivity to the start of deformation. Up to peak strength, both densities exhibited similar SS rates despite different stress levels, indicating AE activity is more closely tied to strain state than to absolute stress. Beyond peak, deviatoric stress softened while the SS rate remained elevated and increasingly intermittent, consistent with persistent localized shearing; the denser specimen showed a larger post-peak rise, aligning with stronger dilation and contact interlocking/breakage. Overall, the results indicate that AE can both detect the initiation of deformation and qualitatively gauge proximity to peak and subsequent transition toward residual strength, supporting its use for early-warning applications in granular soils.
Saad Allah Solh; Sherif L. Abdelaziz
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Session 3: Resilient geotechnical infrastructure
https://doi.org/10.53243/ICPMG2026-414