Investigation of dynamic failure behavior and acoustic emission frequency characteristics of sandstone under drop hammer impact

Abstract

To investigate the dynamic failure behavior and acoustic emission (AE) response patterns of sandstone under impact loading, a drop hammer impact (DHI) AE experimental system was established. The study examined the mechanical properties, energy changes, failure characteristics, and AE waveform signal responses of sandstone at different impact speeds during the failure process. The results indicate that the load-time curve of sandstone failure under DHI can be divided into four stages: compaction stage, linear elastic stage, plastic deformation stage, and post-peak development stage. Under low-speed impacts, the load-time curve exhibits a “step” characteristic. As the impact speed increases, the failure mode of sandstone transitions from rebound failure to puncture failure, and the impact energy absorption also shows an upward trend. The main frequency values of the AEs during sandstone failure are all located in the low-frequency range (0–30 kHz), which is an important characteristic frequency range for sandstone failure under DHI. These research findings contribute to a better understanding of sandstone failure behavior and AE response patterns under DHI, playing an important role in ensuring safe production in coal mines.