Acoustic emission (AE) characteristics of granite after heating and cooling cycles

Ge, Zhenlong; Sun, Qiang

doi:10.1016/j.engfracmech.2018.08.011

Cited by 98 publications

(20 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The decrease in shale b value under complex stress paths only occurs when the stress exceeds 80% of the peak strength, and has nothing to do with bedding planes and loading paths (Wang and Xiao, 2018). Ge and Sun (2018) have studied the effect of heating and cooling conditions on the b value, and considered that the b value increases with the increase of heating and cooling cycles.…”

Section: Introductionmentioning

confidence: 99%

AE Characteristics of Rockburst Tendency for Granite Influenced by Water Under Uniaxial Loading

Zhang

Sun

et al. 2020

Front. Earth Sci.

View full text Add to dashboard Cite

In deep mining, granite is stored with high energy duing to its structural integrity and brittleness. Rock bursts usually occur because stress changes and mining disturbances during mining, which seriously threaten safe production. Focusing on the factor -waterwhich may reduce the brittleness and rockburst tendency of granite, this work discussed the brittleness index and AE characteristics of dry and saturated water granite samples under uniaxial loading. The results show that the peak strength and elastic modulus of the saturated water granite are reduced. The damage degree of the water sample is larger than that of the dry sample, and the brittle failure is significantly reduced. The cumulative number of acoustic emission (AE) events in saturated water granite is significantly reduced compared to the dry sample, which is a decrease of 31.5%. However, AE event rate is higher than that of dry granite in the late loading period; AE quiet period of saturated water granite lasts longer and is more obvious than that of dry granite. Dry granite stores and releases more energy during the whole loading process, and the proportion of high energy level AE events in the later stage of loading is higher. The b value of the two samples show a downward trend with fluctuation in the critical state of fracture and a jump increases at the moment of instability. The decrease of b values of dry granite is larger than that of saturated water granite. Results suggest that the decline of AE b value of granite can be taken as the precursor of rock burst, and water can significantly reduce the rockburst tendency of granite.

show abstract

Section: Introductionmentioning

confidence: 99%

AE Characteristics of Rockburst Tendency for Granite Influenced by Water Under Uniaxial Loading

Zhang

Sun

et al. 2020

Front. Earth Sci.

View full text Add to dashboard Cite

show abstract

“…The increase in amplitude of the elastic modulus is different at different temperatures. (5) The strain corresponding to the upper loads of the granite samples decreases with increasing number of cycles. The variation of the strain corresponding to the upper loads with the number of cycles is relatively flat and it does not change significantly during the first two cycles at 70% loading stress.…”

Section: Discussionmentioning

confidence: 95%

“…A deep understanding of the effects of cyclic temperature and cyclic loading on the mechanical properties of rocks is critical for many high-temperature underground engineering applications, such as thermal energy storage (TES) [1,2], enhanced geothermal systems (EGS) [3][4][5] and compressed air energy storage (CAES) [6]. TES is a storage technology that is used in concentrated solar power plants [2].…”

Section: Introductionmentioning

confidence: 99%

Exploratory Experimental Study on the Mechanical Properties of Granite Subjected to Cyclic Temperature and Uniaxial Stress

Zhao

Jin

2020

Energies

View full text Add to dashboard Cite

This paper investigates the variation of mechanical properties of granite during temperature and stress cycling, which is an important part of evaluating the long-term thermal and mechanical stability of thermal energy storage. Cyclic temperature and loading tests were conducted where the upper limit of cyclic temperature was 100-600 • C, and the upper stress limits were 70% and 85% of the average uniaxial compressive strength (UCS) at the corresponding temperature. The response of stress-strain characteristics of the granite samples to changes in temperature, and cyclic load upper limit, while the number of temperature and loading cycles was comprehensively analyzed. The results show that the temperature and stress cycles have significant effects on the mechanical properties of granite (i.e., stress-strain curve, strength, elastic modulus, and deformation). The elastic modulus of the sample during loading increases gradually. The strain corresponding to the upper loads of the granite samples decreases with an increasing number of cycles. Additionally, the UCS of samples after 10 cycles at 70% loading stress is greater than that at 85% loading stress. The mechanical properties of samples change dramatically during the first and second cycles at 85% loading stress, whereas at 70% loading stress, the mechanical properties change gradually in the first few cycles, and then tend to stabilize. Cyclic hardening is observed at temperatures below 500 • C, where post cyclic UCS is greater than the uncycled average UCS. This phenomenon requires further research.Energies 2020, 13, 2061 2 of 17 reported the effect of cyclic temperature on the physical and mechanical properties of rocks. Rong et al. [11,12] investigated the influence of thermal cycling on the physical and mechanical properties of rock (i.e., marble and granite) through a uniaxial compression test and conducted microscopic observations to investigate the thermal damage of rock sample induced by the treatment of different thermal cycles. Battaglia et al. [15] measured the linear thermal expansion of marbles subjected to thermal cycles utilizing a high-sensitivity apparatus. Lin et al. [16] investigated the variation of residual strain and micro-crack density of granite with cyclic temperature in the range of 600 • C, and explained the mechanism of permanent deformation caused by micro-cracks from the microscopic perspective. Fang [18] analyzed and compared the effects of mechanical properties of marble subjected to thermal treatment and thermal cycling. They showed that the physical and mechanical properties of rock samples deteriorate gradually with an increasing number of temperature cycles. Further, other researchers considered that the deterioration of the mechanical properties of building materials and engineering structures in cold regions with harsh climatic conditions was due to freeze-thaw cycles [19][20][21].Most of the earlier studies on the effect of cyclic loading on the mechanical properties of rocks did not consider the effect of temperature, i....

show abstract

“…Crack initiation and propagation in granite is an energy absorption process and an energy dissipation process that may be monitored by thermal and/or acoustic emission (AE), techniques [16][17][18][19][20]. From theoretical point of view, the fundamental equation that govern time to failure for uniaxial tensile in material is [21 :…”

Section: Acoustic Emission (Ae) Techniquementioning

confidence: 99%

Granite stone subjected to ultrasonic fatigue tests under three point bending modality

Almaraz

Dominguez

Alonso

2019

Frattura Ed Integrità Strutturale

View full text Add to dashboard Cite

Ultrasonic fatigue tests are carried out under the modality of three point bending on the granite stone. The testing specimens present a prismatic shape with the dimensions: 12 x 3 x 0.8 centimeters, in order to be supported by its two ends, and to configure the three point bending modality. Granite specimens are supported on an acrylic structure destined to fix and immobilize the specimens. Vibrating load is applied at the center of testing specimens by a self-designed and fabricated aluminum alloy awl, whose dimensions have been obtained by modal numerical analysis to fit the resonance condition, necessary for the ultrasonic fatigue tests. Experimental results are obtained at room temperature and humidity between 65 and 75%. The fatigue endurance is determined on the granite under this modality of loading, and the fracture surfaces are analyzed to identify the principal trends related to crack initiation and propagation on this material.

show abstract

Acoustic emission (AE) characteristics of granite after heating and cooling cycles

Cited by 98 publications

References 26 publications

AE Characteristics of Rockburst Tendency for Granite Influenced by Water Under Uniaxial Loading

AE Characteristics of Rockburst Tendency for Granite Influenced by Water Under Uniaxial Loading

Exploratory Experimental Study on the Mechanical Properties of Granite Subjected to Cyclic Temperature and Uniaxial Stress

Granite stone subjected to ultrasonic fatigue tests under three point bending modality

Contact Info

Product

Resources

About