Acoustics and Shear Response of Sand-Steel Contacts Through Micromechanical Tests

Abstract Understanding the shear and acoustic responses of soil-metal interfaces is vital for efficient design and monitoring of the geotechnical systems, including soil characterization devices, soil-reinforced structures, buried pipelines, and pile foundations. Applying acoustic emission (AE) based waveguides for monitoring geotechnical structures is emerging as an efficient and economical alternative to existing methods. To the best of the authors’ knowledge, for the first time, the underlying causes of AE and its correlation with shear influencing parameters at particle-steel contacts were explored using a novel micromechanical shear testing apparatus. The experimental results analysed across time and frequency domains reveals micro-tapping induced by the breakage of particle asperities during shearing is the primary source of AE during shear, rather than the frictional mechanisms associated with pure sliding or plowing.