A new method of determining geostresses by the acoustic emission Kaiser effect

2000 ◽  
Vol 37 (3) ◽  
pp. 543-547 ◽  
Author(s):  
H.T. Wang ◽  
X.F. Xian ◽  
G.Z. Yin ◽  
J. Xu
Keyword(s):  
Acoustic Emission ◽  
New Method ◽  
Kaiser Effect

Estimation of Rock In-Situ Stress by Acoustic and Electromagnetic Emission

2006 ◽  
Vol 13-14 ◽  
pp. 357-362 ◽  
Author(s):  
Yasuhiko Mori ◽  
P. Sedlak ◽  
Josef Sikula
Keyword(s):  
Acoustic Emission ◽  
Simultaneous Measurement ◽  
Rock Sample ◽  
Electromagnetic Emission ◽  
In Situ Stress ◽  
New Method ◽  
Acoustic Emission Activity ◽  
Kaiser Effect ◽  
Emission Activity

The Kaiser Effect in acoustic emission is often used for an estimation of the stress to which rocks have been subjected. However, there are cases in which the Kaiser Effect is not clear, since the noises due to the contact and/or the stick slip between the pre-induced fracture surfaces are measured during the reloading process. In such cases, estimation of previous stress is difficult by the conventional method which is based on the acoustic emission activity observed under reloading process. In the tests for the Kaiser Effect on rocks, therefore, the noises must be eliminated from the acoustic emission generated from newly created cracks during the second loading process. Such techniques as analysis of the difference between the acoustic emission activity observed in the first and second reloading and the analysis of the change in the slope of the acoustic emission amplitude distribution have been proposed. In this paper we present a new method by which the maximum previous stress in rocks can be directly estimated without any post signal analysis. In the new method, simultaneous measurement of acoustic and electromagnetic emission during loading test of rock sample is employed. The electromagnetic emission in the deformation of rock sample generates only when the fresh surfaces due to cracking are created in the material, and the source of electromagnetic emission is the electrification between the fresh crack surfaces. This paper describes the simultaneous measurement of acoustic and electromagnetic emission useful for estimating the rock in-situ stress.

Study on Acoustic Emission Signatures during the Process of Edge Chipping for Engineering Ceramics

2011 ◽  
Vol 697-698 ◽  
pp. 93-96 ◽  
Author(s):  
Xiu Jian Tang ◽  
Xin Li Tian ◽  
Jian Quan Wang ◽  
Ya Tao Mao ◽  
F.Q. Li
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Static Load ◽  
Average Frequency ◽  
Displacement Curve ◽  
Edge Chipping ◽  
Kaiser Effect ◽  
Engineering Ceramics ◽  
Highly Active ◽  
Fracture Processes

The developments of edge chipping for engineering ceramics are analyzed. An edge chipping experiment under static load is adopted to study the fracture process of edge chipping. The results show that the fracture processes of edge chipping under different edge distances are similar, which can be divided into four stages based on load-displacement curve. There is obviously Kaiser Effect during the fracture processes of edge chipping. Counts, average frequency, RMS, duration, amplitude and inverse calculation can be used to describe the process of edge chipping for engineering ceramics. Amplitude, duration and average frequency become highly active on the eve of fracture, which can be regard as the omens of edge chipping and used to predict the fracture of edge chipping.

scholarly journals A Simple and Accurate Interpretation Method of In Situ Stress Measurement Based on Rock Kaiser Effect and Its Application

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Kang Zhao ◽  
Shuijie Gu ◽  
Yajing Yan ◽  
Keping Zhou ◽  
Qiang Li ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fractal Dimension ◽  
Principal Stress ◽  
In Situ Stress ◽  
Time Range ◽  
Kaiser Effect ◽  
Time Stress ◽  
Stress Curve ◽  
Interpretation Method

Many deep underground excavation practices show that the size and distribution of in situ stress are the main factors resulting in the deformation and instability of the surrounding rock structure. The in situ stress measured by the Kaiser effect of rock is used by engineers because of its economy and convenience. However, due to the lack of quantitative judgment basis in determining the Kaiser point position, there is a large artificial error in the practical application. In response to the problem, this study systematically investigates the characteristics of rock acoustic emission curve on the basis of the fractal theory and establishes an accurate and simple interpretation method for determining the Kaiser point position. The indoor rock acoustic emission test was carried out by drilling a rock sample at a mine site. By using the conventional tangent method, the cumulative ringing count rate-time-stress curve of rock acoustic emission is analyzed to preliminarily determine the time range of Kaiser point appearance. Considering that the fractal dimension of the rock Kaiser point is lower than the adjacent point, the minimum point of the fractal dimension of this time range can be determined from the fractal dimension-time-stress curve. Such determined point is the Kaiser point. The size of the in situ stress is calculated using an analytical method. Based on the value of the in situ stress, the distribution of the in situ stress in the mining area is further analyzed using the geological structure of the mine. The maximum principal stress is 19.38 MPa, with a direction of N (30°-40°) E, and the minimum principal stress is 8.02 MPa with a direction of N (50°-60°) W. The maximum and minimum principal stresses are approximately in the horizontal plane. The intermediate principal stress is 11.73 MPa in vertically downward. These results are basically consistent with the distribution statistical law of the measured in situ stress fields in the world. The results presented in the study could provide a reference for the later mining, stability evaluation, and support of the surrounding rock.

scholarly journals Damage and fractal evolution trends of sandstones under constant-amplitude and tiered cyclic loading and unloading based on acoustic emission

2019 ◽  
Vol 15 (7) ◽  
pp. 155014771986102
Author(s):  
Dongxu Liang ◽  
Nong Zhang ◽  
Lixiang Xie ◽  
Guangming Zhao ◽  
Deyu Qian
Keyword(s):  
Acoustic Emission ◽  
Cyclic Loading ◽  
Damage Evolution ◽  
Damage Accumulation ◽  
Fractal Dimensions ◽  
Damage Variable ◽  
Constant Amplitude ◽  
Kaiser Effect ◽  
Cyclic Loading And Unloading ◽  
Loading And Unloading

It is of significance to study the damage and destruction of rock under cyclic loading in geotechnical engineering. We determined the trends in damage evolution of sandstone under constant-amplitude and tiered cyclic loading and unloading under uniaxial compression. The results of the study show that (1) the variation of acoustic-emission events was consistent with the stress curves and 89% of all acoustic-emission events occurred during the cycling stages. The observed Kaiser effect was more notable in tiered cycling. (2) The damage variable increased sharply in the cycling stages and its increment was 0.07 higher for tiered cycling than constant-amplitude cycling. Sandstone exhibited greater damage under tiered cyclic loading and unloading. (3) Equations for the evolution of the damage variable under the two cycle modes were obtained by fitting of experimental data. (4) The fractal dimensions of the constant-amplitude cycle were larger than those of the tiered cycle. The process of damage and destruction presents a trend of reducing fractal dimension. The damage accumulation of sandstone under tiered cycling was faster than under constant-amplitude cycling. These results provide references for damage and early warning of rock under both constant-amplitude and tiered cyclic loading and unloading.

scholarly journals Spectral Characteristics of Acoustic Emission in Carbon Fiber-Reinforced Composite Materials Subjected to Cyclic Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Vladimir L. Shkuratnik ◽  
Petr V. Nikolenko
Keyword(s):  
Acoustic Emission ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Spectral Characteristics ◽  
Spectral Composition ◽  
Low Frequency ◽  
Sharp Change ◽  
Kaiser Effect ◽  
Emission Activity ◽  
The Time Domain

The article is devoted to the investigation of the spectral characteristics of acoustic emission signals that appear under various schemes of composite materials loading. The tests involved samples of composites reinforced with layers sheets of carbon fiber fabric and dispersed carbon fibers. Based on the results of laboratory tests, a comparison is made between the traditional parameters of acoustic emission and the complete spectrograms of the acoustic emission response developed with the use of a special algorithm. The relationship between the emission activity and the change in the spectral composition of emission hits is shown. For example, for some composites, the acoustic emission memory effect (Kaiser effect) manifests itself not only in the time domain but also in the spectral domain in a form of a sharp change in the amplitudes in the frequency range 130/150 kHz. Also, when the samples were loaded according to the Brazilian scheme, the presence of the so-called “inverse” Kaiser effect is observed, in which the memory carrier “remembers” the previously experienced level of tensile stresses and reproduces this information during subsequent unloading. Such effect manifests itself in the form of a sharp change in the amplitudes in the low-frequency region of the spectrum.

Investigation of the Kaiser effect in anisotropic rocks with different angles by acoustic emission method

2021 ◽  
Vol 175 ◽  
pp. 107831
Author(s):  
Mehdi Kharghani ◽  
Kamran Goshtasbi ◽  
Majid Nikkah ◽  
Kaveh Ahangari
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Kaiser Effect ◽  
Anisotropic Rocks

Study on Acoustic Emission of Rock Damage Based on Physical Cellular Automata

2012 ◽  
Vol 170-173 ◽  
pp. 179-182
Author(s):  
Zhi Tao Ma ◽  
Yong Ping Wang ◽  
Sai Jiang Liang ◽  
Dong Chuan Gao
Keyword(s):  
Nonlinear Dynamics ◽  
Acoustic Emission ◽  
Cellular Automata ◽  
Elastic Energy ◽  
Physical Phenomenon ◽  
New Method ◽  
Rock Deformation ◽  
Dynamics Analysis ◽  
Rock Damage ◽  
Analysis Method

Rock acoustic emission a physical phenomenon during the rock deformation, it is also an effective method used to study the properties of rock damage. In this article, from the aspects of elastic energy, a discrete nonlinear dynamics analysis method was established based on physical cellular automata. Using this new method, the properties of acoustic emission during the rock deformation and damage were studied, and the results were compared with related previous research achievements, and the results show that this new method based on cellular automata is reasonable and effective.

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