Effect of water content on the failure pattern and acoustic emission characteristics of red sandstone

2021 ◽  
Vol 142 ◽  
pp. 104709
Author(s):  
Kui Zhao ◽  
Daoxue Yang ◽  
Peng Zeng ◽  
Zhen Huang ◽  
Wenkai Wu ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Water Content ◽  
Failure Pattern ◽  
Emission Characteristics ◽  
Red Sandstone ◽  
Effect Of Water

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

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.

scholarly journals Experiment and Mechanism Investigation on Freezing-Thawing of Sandstone with Different Water Contents

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Guilei Song ◽  
Longxiao Chen ◽  
Kesheng Li ◽  
Deng Zhang ◽  
Junhao Xu ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Water Content ◽  
Shear Failure ◽  
Freezing Temperature ◽  
Emission Characteristics ◽  
Underground Engineering ◽  
Empirical Formulas ◽  
Splitting Failure ◽  
Acoustic Emission Test ◽  
Water Contents

Freezing-thawing cycles seriously affect the safety of underground engineering in cold regions. At present, most research studies focus on the effect of number and freezing temperature on freezing-thawing cycles. As another important factor, the mechanism of rock mass water content affecting freezing-thawing is less studied. This paper studied the influence of the water content on mechanical property, microstructure, and acoustic emission characteristics of sandstone. The results indicated that the uniaxial compressive strength (UCS) and elastic modulus (E) of sandstone after 20 freezing-thawing cycles decreased as the water content increased. However, the decreasing rate of UCS gradually decreased, while the decreasing rate of E gradually increased. Furthermore, the empirical formulas of UCS and E about water content were obtained. The porosity and plasticity of sandstone after 20 freezing-thawing cycles increased as the water content increased. The empirical formulas of UCS and E about water content were obtained. The porosity and plasticity of sandstone after 20 freezing-thawing cycles increased as the water content increased. The decreasing trend of UCS with porosity was the same as that of UCS with water content. The failure form of sandstone gradually changed from splitting failure to shear failure. The results of the acoustic emission test showed that the stress-strain curves combined with acoustic emission ring counting could reveal the damage evolution process of sandstone during loading.

EFFECT OF WATER CONTENT ON PROPERTIES OF Na2O, 3SiO2 GLASSES

1982 ◽  
Vol 43 (C9) ◽  
pp. C9-455-C9-458 ◽  
Author(s):  
M. Takata ◽  
M. Tomozawa ◽  
J. Acocella ◽  
J. Molinelli ◽  
C. Y. Erwin ◽  
...  
Keyword(s):  
Water Content ◽  
Effect Of Water

Effect of water content on microwave dielectric properties of building materials

2020 ◽  
Vol 263 ◽  
pp. 120107
Author(s):  
Romain Damez ◽  
Philippe Artillan ◽  
Arthur Hellouin de Menibus ◽  
Cédric Bermond ◽  
Pascal Xavier
Keyword(s):  
Dielectric Properties ◽  
Water Content ◽  
Building Materials ◽  
Microwave Dielectric Properties ◽  
Effect Of Water ◽  
Microwave Dielectric

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.

Sign in / Sign up

Export Citation Format

Share Document