Acoustic emission characteristics and damage model of cement mortar under uniaxial compression

Gu, Qingheng; Ma, Qing; Tan, Yunliang; Jia, Zhichuang; Zhao, Zenghui; Huang, Dongmei

doi:10.1016/j.conbuildmat.2019.04.090

Cited by 43 publications

(13 citation statements)

References 35 publications

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“…Combined with the cumulative parameter time curve in Fig. 8, we can conclude that the cumulative damage evolution process of crown under earthquake can be roughly divided into three stages [17] ： Section AB: Microcracks and pores are compressed and closed at this stage, the lining is mainly elastic deformation; acoustic emission counts and energy is very small, indicating that the acoustic emission signal activity is weak at this stage, called the initial compression elastic stage; Section BC： When the seismic excitation input after a certain time, the microcrack in the lining accelerates to expand and the crack penetrates, acoustic emission counts and energy are very high at this stage, and the corresponding cumulative counts and energy values increase rapidly, which can be seen as a strong acoustic emission signal activity at this stage, called the yielding damage stage. After point C：Lining macroscopic damage phase, acoustic emission activity decreases, the counts and energy value decreases sharply, and the increase of cumulative counts and cumulative energy tends to be gentle, called the residual phase.…”

Section: Analysis Of Damage Process Of Tunnel Crownmentioning

confidence: 84%

Research on tunnel damage process based on acoustic emission technology

Zhu

Liu

Cui

et al. 2022

J. Phys.: Conf. Ser.

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For a long time, it is generally believed that the tunnel has excellent seismic performance and can resist earthquake damage, so it will not be damaged. However, according to the survey of tunnels after the Wenchuan earthquake in China, 110 tunnels were damaged to varying degrees. In this paper, a series of shaking table tests were carried out on the proportional tunnel model under seismic excitation. Acoustic emission technology is combined with seismic excitation to identify and describe the damage of tunnel lining. The tunnel lining strain and acoustic emission signals are collected in the test. In addition, this paper also introduces the use of acoustic emission technology to describe the damage of tunnel lining. Taking the crown as an example, through the correlation analysis of amplitude, counts and energy, it is preliminarily judged that the crown is damaged under working conditions 7 and 8; Then combined with strain analysis, it is proved that the correlation analysis is reasonable. Finally, the rationality of correlation analysis is further explained by the changes of counts, energy, and its cumulative parameters with time. At the same time, the damage process of tunnel lining under seismic excitation is described by defining damage variables, which can be divided into three stages: initial compression elastic stage, yield failure stage and residual stage.

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Section: Analysis Of Damage Process Of Tunnel Crownmentioning

confidence: 84%

Research on tunnel damage process based on acoustic emission technology

Zhu

Liu

Cui

et al. 2022

J. Phys.: Conf. Ser.

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“…To further observe the applicability of the developed model, a comparison between the proposed model and experimental data of two kinds of cement mortar in References [6,39] was made. The cement–sand ratio, elastic modulus E , total strain ε A at the crack closure point, plastic strain ε10 at the crack closure point, residual strength σ cr , and the loading rate are 1:1 and 1:2, 0.925 GPa and 0.837 GPa, 0.019 and 0.021, 0.009 and 0.008, 2.86 MPa and 2.08 MPa, 0.1 mm/min and 1.0 mm/min, respectively.…”

Section: Resultsmentioning

confidence: 99%

Uniaxial Compression Behavior of Cement Mortar and Its Damage-Constitutive Model Based on Energy Theory

Tan

Ning

et al. 2019

Materials

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The mechanical properties of mortar materials in construction are influenced both by their own proportions and external loads. The trend of the stress–strain curve in cracks compaction stage has great influence on the relationship between the strength and deformation of cement mortar. Uniaxial compression tests of mortar specimens with different cement–sand ratios and loading rates were carried out, and the stored and dissipated energies were calculated. Results indicated that the elastic modulus and strength of mortar specimens increase with the cement–sand ratio and loading rate. The energy dissipation shows good consistency with the damage evolution. When the loading rate is less than 1.0 mm/min, most of the constitutive energy at the peak point is stored in the specimen and it increase with cement–sand ratio. A simple representation method of axial stress in cracks compaction stage was proposed and an energy-based damage constitutive model—which can describe well the whole process of cement mortar under uniaxial compression—was developed and verified.

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“… 66 , 67 In the study of rock damage based on AE data, standardized cumulative energy, ringing, and other characteristic parameters have been widely used to characterize rock damage. 68 , 69 The dissipated energy ratio and standardized cumulative dissipated energy are also commonly used to assess rock damage. 70 , 71 However, regarding the total stress–strain curve, there is little research on the characteristics of the energy transformation value at different stages, correlations between the energy evolution and deformation damage, and energy value expressions.…”

Section: Plastic Damage Energy Evolution Model and Complete Stress–st...mentioning

confidence: 99%

Strength Degradation and Fracture Propagation of Repeatedly Immersed Artificial Dam Samples under Uniaxial Cyclic Loading–Unloading

et al. 2023

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The use of underground reservoirs is a critical technique for achieving sustainable coal and water resources in many ecologically fragile mines in western China. Concrete samples subject to repeated water immersion and cyclic loading−unloading (CLU) operations were obtained from an underground artificial reservoir dam in Chahasu Colliery to study their strength damage and fracture propagation behavior. The variation in water content of the samples according to immersion times were divided into the rapid growth stage (0−10 h), slow growth stage (10−60 h), and stable stage (>60 h). With an increase in immersion times (IIT), the saturated water content of the coal samples logarithmically increased to 7.02%, and the ultrasonic wave velocity decreased by 10.44%. According to the increasing trend of plastic damage energy density, the total stress−strain curve was divided into four fracture stages. The total energy and elastic energy densities increased nonlinearly with the increase in cycles, whereas the plastic damage energy density first decreased and then increased. The plastic damage energy ratio at the stress peak point of the samples under different sequential times of immersion was 0.18, 0.29, 0.28, 0.58, and 0.61. The initial fracture development and fracture damage thresholds of the samples decreased by 20 and 50% with IIT, respectively. However, the proportion of the fracture closure and initial fracture development thresholds of the samples showed an increasing quadratic trend with IIT. Based on the low ratio of rise time to amplitude and high average frequency, the fracture mode of the samples under repeated water immersion was mainly tensile fracture. Acoustic emission events with energy higher than 10 4 aJ spread from the center with repeated water immersion. When the CLU was greater than 6, the plastic damage energy of the fitted three-dimensional surface increased nonlinearly with IIT. The energy parameter−plastic damage energy ratio was introduced to help develop a theoretical model for describing the complete stress−strain damage evolution of repeatedly immersed concrete samples under CLU. The paper provides technical references for improving the long-term strength design of concrete artificial dams of underground reservoirs.

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Acoustic emission characteristics and damage model of cement mortar under uniaxial compression

Cited by 43 publications

References 35 publications

Research on tunnel damage process based on acoustic emission technology

Research on tunnel damage process based on acoustic emission technology

Uniaxial Compression Behavior of Cement Mortar and Its Damage-Constitutive Model Based on Energy Theory

Strength Degradation and Fracture Propagation of Repeatedly Immersed Artificial Dam Samples under Uniaxial Cyclic Loading–Unloading

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