Characterizing bond breakages in cemented sands using a MEMS accelerometer

Abstract

In this study, a raicroelectromechanical systems (MEMS) accelerometer, MEMS A (1-3 kHz), and a commercially available piezoelectric acoustic emission (AE) sensor, PZT (125-750 kHz), were used to capture AE responses in uncemented and cemented sands during triaxial compression tests. The AE rates measured in the cemented sands by both sensors demonstrated a similar trend and showed a strong resemblance to the stress-strain response. The bond breakages and the associated AE activities were mild at small strains and increased afterwards to initiate yielding. After the peak stress, shear banding gradually formed and the AE rate distinctly dropped. These observations suggest that a MEMS accelerometer can function as an effective AE sensor to detect the bond-breakage process in cemented sands. In addition, a PZT is more sensitive to the AE detection for cemented sands but a MEMSA starts earlier to capture AE and also continue to capture AE from the shear band at large strains while the PZT only measures a few or no AE activities. Copyright © 2009 by ASTM International.