Progressive Failure Characterization of Sandstone from Yingjinshan Area in Qinghai-Tibet Plateau

Wang, Xinzhong; Xie, Heping; Zhang, Ru; Zhang, Guangze; Xu, Zhengxuan; Deng, Jiewei; Wang, Dong; Li, Cunbao; Feng, Gan; Zhang, Zetian; Ren, L.

doi:10.1007/s00603-022-02999-1

Cited by 15 publications

(4 citation statements)

References 65 publications

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“…For the case of σ 3 = 0.1 MPa, the interval belonging to the stage 2–3 on the stress-strain curve was divided into three substages shown as (i), (ii), (iii) in Fig 8a . The length of the interval of this stage is longer in the case of σ 3 = 2 MPa due to the relatively higher confining stress [ 22 , 24 , 62 , 63 ]. Thereby, the stage 2–3 of the stress-strain curve was now divided into six substages presented as (i), (ii), (iii), (iv), (v), and (vi) in Fig 8b .…”

Section: Discussionmentioning

confidence: 99%

“…Thanks to the acoustic emission (AE) technique in the laboratory, monitoring analyses can be conducted to observe the pre-failure microcrack accumulation [15][16][17][18][19][20][21][22][23][24] as well as to detect damage acceleration in brittle rocks consisting of pre-existing flaws [25][26][27][28][29][30][31]. Propagation and distribution of microcracks with increasing axial stress can be followed in rock samples by measuring the energy released.…”

Section: Introductionmentioning

confidence: 99%

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Stress levels of precursory strain localization subsequent to the crack damage threshold in brittle rock

Göğüş

Avşar

2022

PLoS ONE

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Micromechanical cracking processes in rocks directly control macro mechanical responses under compressive stresses. Understanding these micro-scale observations has paramount importance in predicting macro-field problems encountered in rock engineering. Here, our study aims to investigate the development of precursory damage zones resulting from microcracking pertinent to macro-scale rock failure. A series of laboratory tests and three-dimensional (3D) numerical experiments are conducted on andesite samples to reveal the characteristics of damage zones in the form of strain fields. Our results from discrete element methodology (DEM) predict that the crack damage threshold (σcd) values are 61.50% and 67.44% of relevant peak stress under two different confining stresses (σ3 = 0.1 MPa and σ3 = 2 MPa), respectively. Our work evaluates the strain fields within the range of the σcd to the peak stress through discrete analysis for both confining stresses. We note that the representative strain field zones of failure are not observed as soon as the σcd is reached. Such localized zones develop approximately 88% of peak stress levels although the confinement value changes the precursory strain localization that appears at similar stress levels. Our results also show that the distinct strain field patterns developed prior to failure control the final size of the macro-damage zone as well as their orientation with respect to the loading direction (e.g 17° and 39°) at the post-failure stage. These findings help to account for many important aspects of precursory strain field analysis in rock mechanics where the damage was rarely quantified subtly.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stress levels of precursory strain localization subsequent to the crack damage threshold in brittle rock

Göğüş

Avşar

2022

PLoS ONE

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“…Poisson's ratio is of great importance for the describing of the elastic mechanical properties of rocks (Tang et al 2001;Gercek 2007) and is frequently employed in the analysis of deformation ( Zhang and Chen 2006;Liang et al 2012;Ji et al 2018;Li et al 2021), progressive failure (Bieniawski and Bernede 1978;Eberhardt et al 1998;Wang et al 2011;Davarpanah et al 2019) and dynamic properties of rocks (Xing et al 2018(Xing et al , 2021. The rock mechanics community has long followed the assumptions of classical elastic mechanics by considering Poisson's ratio as an elastic constant to simplify the analyses.…”

Section: Introductionmentioning

confidence: 99%

Variation of Possion’s ratio of hard rocks during compression and an innovative determination method based on axial loading-unloading test

Yang,

Fan,

Gao

et al. 2024

Preprint

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The Poisson’s ratio of hard rock exhibits a marked stress dependence, which is contrary to its mechanical definition as an elastic constant. Thus, it is of great importance to determine the Poisson’s ratio through a reasonable method. To investigate the Poisson effect of multiple types of hard rocks (sandstone, basalt, granite, and marble), the uniaxial loading–unloading tests are carried out. The test results indicate that whether the tangent Poisson’s ratio or the average Poisson’s ratio, all gradually increases with the stress level. And the stress dependence of the average Poisson’s ratio under the unloading path is reduced, which is significant in the low and medium stress intervals. Appropriately increasing the number of loading–unloading cycles can also improve the stability of the average Poisson’s ratio to some extent. Based on this, a new method for testing the average Poisson’s ratio is proposed, which can effectively exclude the effect of irreversible displacement of rocks and improve the stability of the average Poisson’s ratio. The test procedure is simple and has good application prospects.

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“…The acoustic emission (AE) measurement is a robust and well-known tool for monitoring the microcrack accumulation in rocks during the loading stage [16][17][18][19][20][21][22]. The AE in geological materials is defined as a transient elastic wave generated from the rapid release of unit deformation energy during micro-fractures and fractures (Hardy, 1972).…”

Section: Introductionmentioning

confidence: 99%

Thermal effect on the geo-engineering characteristics of a rock salt

Özcan

2023

PLoS ONE

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Rock salt caverns are considered one of the best hosts to store oil, natural gas, radioactive and toxic wastes due to their low permeability, self-healing characteristics and wide distribution on the Earth. Stored nuclear waste in rock salts will radiate for many years. Therefore, the thermal energy and also temperature in the host environment will increase depending on time. In this study, P-wave velocity (Vp), Brazilian tensile strength (σt), uniaxial compression strength (σc) of Çankırı rock salt were investigated under different temperatures ranging from 20°C to 250°C since the temperature is a factor that causes changes in some physical and geo-mechanical properties of rocks. The acoustic emission technique was utilized during uniaxial compression strength tests, to monitor the crack accumulation. Additionally, X-ray micro-computed tomography technique was employed to observe the microstructure and determine the porosity of rock salt samples depending on the temperature. The Vp and the σt of Çankırı rock salt decrease with increasing temperatures of samples whereas the σc increases. The ductility of rock salt tends to increase with augmented temperature and the axial strain at the ultimate stress level is 2.96% at 20°C whereas it reaches up to 6.29% at 250°C. The AE activity of rock salt generates at the early stages of loading and AE count prominently increases with the increasing temperature of samples. Therefore, the stress levels of crack initiation (σi) and crack damage (σcd) thresholds were reached earlier than the previous one with each temperature increment. According to X-ray micro-CT images of rock salts, the number of cracks increased markedly in thermally treated rock salt samples and therewith the porosity increases from 1.12% to 2.73% with an increase in temperature from 50°C to 250°C.

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Progressive Failure Characterization of Sandstone from Yingjinshan Area in Qinghai-Tibet Plateau

Cited by 15 publications

References 65 publications

Stress levels of precursory strain localization subsequent to the crack damage threshold in brittle rock

Stress levels of precursory strain localization subsequent to the crack damage threshold in brittle rock

Variation of Possion’s ratio of hard rocks during compression and an innovative determination method based on axial loading-unloading test

Thermal effect on the geo-engineering characteristics of a rock salt

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