scholarly journals Study on Test Method of Rock Acoustic Emission and Damage Evolution Characteristics Under Triaxial Compression

2014 ◽  
Author(s):  
Yongjie Yang ◽  
Depeng Ma ◽  
Yanxin He ◽  
Luyi Xing
Keyword(s):  
Acoustic Emission ◽  
Damage Evolution ◽  
Triaxial Compression ◽  
Test Method ◽  
Evolution Characteristics

Study on mechanical properties and damage evolution of carbonaceous shale under triaxial compression with acoustic emission

2021 ◽  
pp. 105678952199119
Author(s):  
Kai Yang ◽  
Qixiang Yan ◽  
Chuan Zhang ◽  
Wang Wu ◽  
Fei Wan
Keyword(s):  
Mechanical Properties ◽  
Acoustic Emission ◽  
Water Content ◽  
Damage Evolution ◽  
Damage Assessment ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Damage Variable ◽  
Natural State ◽  
Carbonaceous Shale

To explore the mechanical properties and damage evolution characteristics of carbonaceous shale with different confining pressures and water-bearing conditions, triaxial compression tests accompanied by simultaneous acoustic emission (AE) monitoring were conducted on carbonaceous shale rock specimens. The AE characteristics of carbonaceous shale were investigated, a damage assessment method based on Shannon entropy of AE was further proposed. The results suggest that the mechanical properties of carbonaceous shale intensify with increasing confining pressure and degrade with increasing water content. Moisture in rocks does not only weaken the cohesion but also reduce the internal friction angle of carbonaceous shale. It is observed that AE activities mainly occur in the post-peak stage and the strong AE activities of saturated carbonaceous shale specimens appear at a lower normalized stress level than that of natural-state specimens. The maximum AE counts and AE energy increase with water content while decrease with confining pressure. Both confining pressure and water content induce changes in the proportions of AE dominant frequency bands, but the changes caused by confining pressure are more significant than those caused by water content. The results also indicate that AE entropy can serve as an applicable index for rock damage assessment. The damage evolution process of carbonaceous shale can be divided into two main stages, including the stable damage development stage and the damage acceleration stage. The damage variable increases slowly accompanied by a few AE activities at the first stage, which is followed by a rapid growth along with intense acoustic emission activities at the damage acceleration stage. Moreover, there is a sharp rise in the damage evolution curve for the natural-state specimen at the damage acceleration stage, while the damage variable develops slowly for the saturated-state specimen.

scholarly journals Method Improvement and Effect Analysis of Triaxial Compression Acoustic Emission Test for Coal and Rock

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Yan Zhou ◽  
Chuanxiao Liu ◽  
Depeng Ma
Keyword(s):  
Acoustic Emission ◽  
Rock Mechanics ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Outer Wall ◽  
Test System ◽  
Test Method ◽  
Effect Analysis ◽  
High Confining Pressure ◽  
Ae Signals

In the study of the acoustic emission (AE) characteristics of rock samples or coal samples under triaxial compression conditions, most scholars carry out relevant experiments by placing the AE detector on the outer wall of the triaxial chamber of the rock mechanics test system. Owing to the continuous obstruction of AE signals by hydraulic oil in the triaxial chamber and the frequent interference of external noises, the final experimental data cannot objectively and truly reflect the essential characteristics of AE of rock or coal under triaxial compression conditions. It is difficult to scientifically guide and accurately predict precursory information of rock’s or coal’s rupture and instability. Based on this, a series of improvements and optimizations were made to the original triaxial compression AE test method, which is based on the modification of the communication interface of the rock mechanics test system, a test head which can put the AE detector into the triaxial chamber and withstands high confining pressure, in order to obtain the true, comprehensive, and reliable AE signals. It is of considerable significance to the scientific determination of the precursory characteristics of rock’s or coal’s rupture and instability.

scholarly journals Researches on Damage Evolution and Acoustic Emission Characteristics of Rocks

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yong Chen ◽  
Yugui Yang ◽  
Feng Gao ◽  
Xiangxiang Zhang
Keyword(s):  
Acoustic Emission ◽  
Elastic Modulus ◽  
Damage Evolution ◽  
Constitutive Relations ◽  
Damage Model ◽  
Petroleum Reservoir ◽  
Evolution Characteristics ◽  
Damage Constitutive Model ◽  
Rock Specimens ◽  
Statistical Damage

Mechanical parameters of the rock are important for the design of geotechnical, mining engineering, and petroleum reservoir projects. Many researches have suggested that the mechanical variables of rock specimens, such as compressive strength and elastic modulus, do not have a single fixed value. Uncertainty in the basic mechanical variables of the rock material can significantly affect the structural performance and safety. In this study, a series of compression experiments with acoustic emission have been performed on rock specimens. The damage evolution characteristics of the rock in the process of loading were studied, and the macromechanical behaviors were obtained at the same time. Distribution characteristics of the strength and elastic modulus as random variables are illustrated, and the statistical damage model is presented by the authors to formulate analytical constitutive relations for deformation behavior. The comparisons between predicted results and experimental data show that the statistical damage constitutive model could well reproduce the deformation process of rock materials.

Acoustic Emission Characteristics and Damage Evolution of Coal at Different Depths Under Triaxial Compression

2020 ◽  
Vol 53 (5) ◽  
pp. 2063-2076 ◽  
Author(s):  
Zheqiang Jia ◽  
Heping Xie ◽  
Ru Zhang ◽  
Cunbao Li ◽  
Man Wang ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Damage Evolution ◽  
Triaxial Compression ◽  
Emission Characteristics ◽  
Different Depths

Diagnosis of damage evolution process for asphalt mixtures using pattern recognition with acoustic emission signals

2021 ◽  
Vol 280 ◽  
pp. 122536
Author(s):  
Xin Qiu ◽  
Jingxian Xu ◽  
Wenyi Xu ◽  
Qing Yang ◽  
Feng Wang ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Acoustic Emission ◽  
Damage Evolution ◽  
Asphalt Mixtures ◽  
Evolution Process
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