The investigation on tensile failure of active waveguide structure by acoustic emission measurements

Based on the principle of active waveguide monitoring for rock slope, the physical test was designed, and the acoustic emission (AE) characteristics of the active waveguide structure were studied. The results show that the signal distribution range in the parameter correlation diagram expands from the low-amplitude to the high-amplitude region with tensile load increase. The AE amplitude rises from 35 to 55 dB to 60-85 dB, accompanied by a continuous increase in AE energy. Subsequently, continuous signals appear in the frequency bands of 50-150 kHz, accounting for 15% of the total AE events. When the tensile stress is near the peak stage, the AE signal increases sharply, the signal amplitude is distributed in the range of 40-90dB, and a large number of high-frequency signals appear in the range of 300-400 kHz, accounting for 32% of the total effective AE events. The energy amplitude level of the high-frequency band is in the range of 30%-35%. Through a series of tensile load (0.1-1.0kN/s) tests, it is found that the statistical AE counts are sensitive to the loading rate, which can effectively distinguish the tensile stage and cracking evolution trend of the active waveguide structure. The active waveguide structure can monitor the internal deformation and failure characteristics of the rock slope, so as to provide some reference for the early warning.