Cracking Characteristics and Damage Assessment of Filled Rocks Using Acoustic Emission Technology

Abstract

Natural flaws containing fillings strongly affect the mechanical properties and failure process of rocks in practical engineering. In this work, uniaxial compression tests are performed on filled and unfilled red sandstone specimens containing two parallel dentate flaws. Two monitoring technologies––acoustic emission (AE) and high-speed camera––are employed to record the cracking process of the flawed rocks. The effects of filling and ligament angles on the mechanical properties of the flawed rocks are analyzed. The relationship between AE parameters and stress–strain curves is established in order to evaluate the cracking process. The fracture behaviors between the filled and unfilled specimens are qualitatively compared. An intensity analysis method, based on the historic index and severity, is employed to assess the damage level of the flawed rocks. Simultaneously, a judgmental design criterion, including safety, early warning, and instability, is developed, which can be employed to evaluate the stability of rock structures.