Dynamic Mechanical Behavior of Dry and Water Saturated Igneous Rock with Acoustic Emission Monitoring

The uniaxial cyclic loading tests have been conducted to study the mechanical behavior of dry and water saturated igneous rock with acoustic emission (AE) monitoring. The igneous rock samples are dried, naturally immersed, and boiled to get specimens with different water contents for the testing. The mineral compositions and the microstructures of the dry and water saturated igneous rock are also presented. The dry specimens present higher strength, fewer strains, and rapid increase of AE count subjected to the cyclic loading, which reflects the hard and brittle behavior and strong burst proneness of igneous rock. The water saturated specimens have lower peak strength, more accumulated strains, and increase of AE count during the cyclic loading. The damage of the igneous rocks with different water contents has been identified by the Felicity Ratio Analysis. The cyclic loading and unloading increase the dislocation between the mineral aggregates and the water-rock interactions further break the adhesion of the clay minerals, which jointly promote the inner damage of the igneous rock. The results suggest that the groundwater can reduce the burst proneness of the igneous rock but increase the potential support failure of the surrounding rock in igneous invading area. In addition, the results inspire the fact that the water injection method is feasible for softening the igneous rock and for preventing the dynamic disasters within the roadways and working faces located in the igneous intrusion area.

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

International Journal of Distributed Sensor Networks ◽

10.1177/1550147719861020 ◽

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.

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Experimental Study of Mechanical Behavior of Interlayer Staggered Zone under Cyclic Loading and Unloading Condition

International Journal of Geomechanics ◽

10.1061/(asce)gm.1943-5622.0001602 ◽

2020 ◽

Vol 20 (3) ◽

pp. 04019187 ◽

Cited By ~ 3

Author(s):

Shuqian Duan ◽

Quan Jiang ◽

Dingping Xu ◽

Guofeng Liu

Keyword(s):

Experimental Study ◽

Cyclic Loading ◽

Mechanical Behavior ◽

Cyclic Loading And Unloading ◽

Loading And Unloading

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Mechanical Behavior of Shale Rock under Uniaxial Cyclic Loading and Unloading Condition

Advances in Civil Engineering ◽

10.1155/2018/9750480 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 6

Author(s):

Baoyun Zhao ◽

Dongyan Liu ◽

Ziyun Li ◽

Wei Huang ◽

Qian Dong

Keyword(s):

Cyclic Loading ◽

Mechanical Behavior ◽

Creep Behavior ◽

Peak Stress ◽

Creep Model ◽

Cycle Number ◽

Shale Rock ◽

Cyclic Loading And Unloading ◽

Residual Strains ◽

Loading And Unloading

In order to investigate the mechanical behavior of shale rock under cyclic loading and unloading condition, two kinds of incremental cyclic loading tests were conducted. Based on the result of the short-term uniaxial incremental cyclic loading test, the permanent residual strain, modulus, and damage evolution were analyzed firstly. Results showed that the relationship between the residual strains and the cycle number can be expressed by an exponential function. The deformation modulus E50 and elastic modulus ES first increased and then decreased with the peak stress under the loading condition, and both of them increased approximately linearly with the peak stress under the unloading condition. On the basis of the energy dissipation, the damage variables showed an exponential increasing with the strain at peak stress. The creep behavior of the shale rock was also analyzed. Results showed that there are obvious instantaneous strain, decay creep, and steady creep under each stress level and the specimen appears the accelerated creep stage under the 4th stress of 51.16 MPa. Based on the characteristics of the Burgers creep model, a viscoelastic-plastic creep model was proposed through viscoplastic mechanics, which agrees very well with the experimental results and can better describe the creep behavior of shale rock better than the Burgers creep model. Results can provide some mechanics reference evidence for shale gas development.

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Damage precursor of construction rocks under uniaxial cyclic loading tests analyzed by acoustic emission

Construction and Building Materials ◽

10.1016/j.conbuildmat.2019.02.074 ◽

2019 ◽

Vol 206 ◽

pp. 169-178 ◽

Cited By ~ 20

Author(s):

Li Dexing ◽

Wang Enyuan ◽

Kong Xiangguo ◽

Jia Haishan ◽

Wang Dongming ◽

...

Keyword(s):

Acoustic Emission ◽

Cyclic Loading ◽

Loading Tests ◽

Damage Precursor ◽

Cyclic Loading Tests

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Experimental study on acoustic emission frequency characteristics of granite under different cyclic loading and unloading

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/619/1/012018 ◽

2020 ◽

Vol 619 ◽

pp. 012018

Author(s):

Tan Jie ◽

Song Zhaoyang ◽

Wu Zaihai ◽

Ning Fangbo

Keyword(s):

Experimental Study ◽

Acoustic Emission ◽

Cyclic Loading ◽

Frequency Characteristics ◽

Emission Frequency ◽

Cyclic Loading And Unloading ◽

Loading And Unloading

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Creep Behaviour in Reinforced Masonry Walls Interpreted by Acoustic Emission

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.417-418.237 ◽

2009 ◽

Vol 417-418 ◽

pp. 237-240 ◽

Cited By ~ 2

Author(s):

Pietro G. Bocca ◽

Giuseppe Lacidogna ◽

Alessandro Grazzini ◽

Amedeo Manuello ◽

Davide Masera ◽

...

Keyword(s):

Acoustic Emission ◽

Cyclic Loading ◽

Damage Evolution ◽

Creep Behaviour ◽

Fracture Propagation ◽

Masonry Walls ◽

Innovative Methods ◽

Reinforced Masonry ◽

Loading Tests ◽

Cyclic Loading Tests

An experimental analysis on a set of strengthened masonry walls has been carried out by means of cyclic loading tests in order to simulate the creep effects. The damage evolution of specimens reinforced by traditional or innovative methods is evaluated by the Acoustic Emission (AE) technique. The AE time dependence during fracture propagation is analysed through a power law. In addition, the AE frequency analysis is used to obtain information on the criticality of the ongoing process.

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Experimental and numerical studies on fracture characteristics of notched granite beams under cyclic loading and unloading

The Journal of Strain Analysis for Engineering Design ◽

10.1177/0309324720923218 ◽

2020 ◽

Vol 56 (1) ◽

pp. 3-17

Author(s):

Xiaojing Li ◽

Peijie He ◽

Jianhui Tang ◽

Xudong Chen

Keyword(s):

Acoustic Emission ◽

Cyclic Loading ◽

Correlation Method ◽

Average Frequency ◽

Test System ◽

Underground Engineering ◽

Three Point Bending ◽

Cyclic Loading And Unloading ◽

Loading And Unloading ◽

Felicity Ratio

In underground engineering, such as mining engineering and deep tunnel engineering, the rock is often loaded and unloaded repeatedly. The strength of rock under cyclic load is lower than that under static load. To obtain the fracture response of the rock, the three-point bending tests of notched granite beams under cyclic loading and unloading were carried out with Electro-hydraulic Servo Material Test System. The acoustic emission technology was adopted to monitor the acoustic emission events of sample in the process of fracture. It is revealed that the fracture toughness of granite under cyclic loading and unloading is lower than that under static loading. Based on the acoustic emission energy obtained from monitoring, the damage evolution during cyclic loading and unloading was analyzed. The fracture mode of granite samples is analyzed by the RA value-average frequency correlation method. And the Felicity ratio during the loading and unloading cycle was calculated to evaluate the severity of initial damage of the material. It is revealed that Kaiser effect appears only in the elastic deformation stage of cyclic loading unloading bending. The Holmquist–Johnson–Cook damage constitutive model and Weibull distribution were used to establish the heterogeneous granite model. And the three-point bending of the model under cyclic loading and unloading was simulated to disclose the crack growth mechanism of rock. The study may provide some references for rock instability control in geotechnical engineering construction.

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Experimental Study on Mechanical Properties and Acoustic Emission Characteristics of Water Bearing Sandstone under Stable Cyclic Loading and Unloading

Shock and Vibration ◽

10.1155/2020/9472656 ◽

2020 ◽

Vol 2020 ◽

pp. 1-15

Author(s):

Xinzhan Qin ◽

Yu Zhou ◽

Manchao He

Keyword(s):

Mechanical Properties ◽

Acoustic Emission ◽

Cyclic Loading ◽

Water Content ◽

Coal Mines ◽

Surrounding Rock ◽

Emission Characteristics ◽

Cyclic Loading And Unloading ◽

Loading And Unloading ◽

Pumped Storage

Due to the adjustment of energy structure, a large number of coal mines are abandoned. Considering the environmental and economic effects, many experts proposed to use the abandoned mine cavern as the reservoir of the pumped storage power station. Furthermore, considering the long-term effects of repeated pumping and drainage and hydrodynamic pressure on the surrounding rock in coal mines, a large amount of sandstone was collected from the Ruineng coal mine in Yan’an city to carry out a series of laboratory tests. Through uniaxial compression testing of rock samples with different water content rates, combined with acoustic emission (AE) analysis, the strength softening and macrodeformation characteristics are obtained, and the influence of water content on acoustic emission characteristics is clarified. The mechanical properties of water bearing rock under cyclic loading and unloading experiments with varying upper limits are obtained using a triaxial test system, and the precursory information of rock failure is captured, providing significant guidance for stability analysis and instability warning for surrounding rock in pumped storage power stations.

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