Experimental Study on Acoustic Emission Characteristics of Granite and Sandstone under Uniaxial Compression

Abstract

In order to better apply acoustic emission technology to engineering practice, this paper carried out indoor acoustic emission test, and uniaxial compression tests of granite and sandstone under monotonic loading and grading loading were carried out and monitored. The influencing factors of the acoustic emission characteristics of the two rock samples were discussed and the characteristics of the acoustic emission signals corresponding to different stages of rock failure were analyzed. The analysis of the test results includes the curve fitting relationship between the AE event count rate, energy rate, and stress time and the changes of AE event count rate and energy rate under different loading methods. The results of the study are as follows: there is a quiet zone in the acoustic emission event before the rock is destroyed and destabilized, and the higher the rock strength, the more obvious the quiet zone; this important feature can be used as a precursor feature of rock mass failure for prediction, and the rock acoustic emission energy rate is more obvious in the quiet area before destruction than the acoustic emission event rate; rock acoustic emission has experienced initial compaction zone, rising zone, peak zone, and descending zone, whether different rocks go through each stage and how long each stage lasts is related to the nature of the rock; under different loading methods, the failure mechanism of rock is different; the different loading rates of monotonic loading and grading loading will affect the change rate of acoustic emission.

Rock Crack Initiation Triggered by Energy Digestion

“…Due to the heterogeneity of rock materials, not all external work is converted into elastic strain energy and stored inside the material, and it is accompanied by other forms of energy dissipation, such as elastic strain energy[28], acoustic emission [29][30][31] that releases energy in the form of elastic waves phenomenon: deformation energy [32], which causes the internal state of the material to change, thermal energy [33], and so on. This portion of the energy is primarily used to reconstruct the internal stress eld distribution, as well as to generate and decimate micro-cracks, which have been observed by the acoustic emission study of rock specimens under uniaxial loading [23, 26, 29-32, 34, 35].…”

Mechanical properties and acoustic emission characteristics of basalt fiber reinforced cemented silty sand subjected to freeze-thaw cycles

“…As a dynamic and nondestructive evaluation method, acoustic emission (AE) technology can directly reflect the damage inside the material from deformation to failure [24], which has been widely used in the fields of geotechnical engineering, seismic monitoring and rock failure prediction [25][26][27][28]. Mao and Towhata [29] used AE detection to monitor the single-particle fragmentation process under static action, found that the AE characteristics of particle fragmentation process were significant, at first the AE signal activity was relatively low, then entered the inactive period, finally, it was significantly active again and exhibited high-frequency AE signal aggregation prior to impending fracture failure, which provided important information for elucidating the initiation and propagation of internal cracks during particle crushing.…”

Creep mechanical properties and creep damage model of sandstone considering temperature effect based on acoustic emission

“…[32][33][34][35][36][37] AE signals can be used to determine the evolution process of internal cracks in rocks and thus capture the precursor information of rock instability and failure. Scholars used AE characteristic parameters to study the characteristics and processes of rock rupture, such as AE count, [38][39][40] AE amplitude, 41,42 AE frequency, 43,44 and AE energy. 11,12 In this paper, AE technology was employed to monitor uniaxial compression and creep experimental process of high-temperature heat treated sandstone in real time.…”