Study on Staged Damage Behaviors of Rock-like Materials with Different Brittleness Degrees Based on Multiple Parameters

Abstract

Understanding the brittle fracture behavior of rock is crucial for engineering and Earth science. In this paper, based on acoustic emission (AE) and laser Doppler vibration (LDV) monitoring technology, the staged damage behaviors of rock-like materials with different brittleness degrees under uniaxial compression are studied via multiple parameters. The results show that the brittleness degree determines the fracture mode. As the specimen’s brittleness degree increases, the tensile failure increases and shear failure decreases. AE activity is enhanced at the crack damage point. With an increasing specimen brittleness degree, different instability precursor information is shown during the unstable crack growth stage: the AE b value changes from the fluctuating to continuously decreasing state, and the natural frequency changes from the stable fluctuation to upward fluctuation state. The AE b value near the stress drop is the smallest, and it decreases with an increasing brittleness degree. The natural frequency reduction indicates the rock-like fracture. The natural frequency is a symbolic index that reflects staged damage characteristics and predicts the amount of energy released by brittle failure. These findings provide guidelines for rock stability monitoring and provide support for better responses to stability evaluations of rock slopes, rock collapses, and tunnel surrounding rock in engineering.

A Review on Concrete Structural Properties and Damage Evolution Monitoring Techniques

“…However, a rapid decrease in the b-value is observed during the yielding stage, which can serve as an indicator of concrete condition [37]. Furthermore, AE signals generated from the fracture of concrete with different levels of brittleness exhibit discernible variations, with the b-value in proximity to the stress drop gradually decreasing with an increasing brittleness degree [38]. Moreover, AE signals generated from concrete cracking are closely associated with factors such as concrete size, mode of force application, and tensile rate.…”