Fracture evolution and failure characteristics of sandstone under freeze-thaw cycling by computed tomography

Song, Yongjun; Tan, H.; Yang, Huimin; Chen, Shaojie; Che, Yongxin; Chen, Jiaxing

doi:10.1016/j.enggeo.2021.106370

Cited by 46 publications

(9 citation statements)

References 36 publications

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“…Liu et al (2019) thought that freeze-thaw times lead to pore radius expansion, and the radius of these expansion pores was mainly concentrated on 0-40 μm. Song et al (2021) used C-T scanning technology to perform layered scanning of freeze-thaw times of rock, which found that as the number of freeze-thaw times increased, the volume fraction of internal macropores increased rapidly. Niu et al (2021) observed the mesostructure of freeze-thaw sandstone by scanning electron microscopy and concluded that the smoothness of the sandstone interior played a dominant role in rock failure.…”

Section: Introductionmentioning

confidence: 99%

Study on the pore structure characteristics and damage constitutive model of sandstone under freeze-thaw conditions

Jin²,

Wu³

et al. 2023

Front. Earth Sci.

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Rocks in Northwest China are often affected by the combined action of freeze-thaw and load erosion. Therefore, in order to better understand the mechanical properties of rocks in seasonal frozen areas and the meso-damage caused by freeze-thaw erosion, uniaxial compression tests, electron microscope scanning tests, X-ray diffraction tests (XRD) and mercury intrusion tests (MIP) were carried out on five sandstone samples with different freeze-thaw times, and the mechanical parameters and meso-damage characteristics of sandstone samples with different freeze-thaw times were obtained. Fractal theory was used to analyze the change in pore volume of sandstone after freeze-thaw cycles. Finally, the damage constitutive equation under the coupling action of freeze-thaw damage and load was established based on Lemaitre’s equivalent effect variation criterion. The results showed that the type of sandstone is a porous coarse-grained sandstone. With the increased freeze-thaw times, the compressive strength and cohesion of sandstone gradually decreased, and the closed pores in sandstone gradually connected, leading to the visible internal macroscopic cracks. Affected by freeze-thaw times, the volume proportion of large pores (100–1,000 µm) in sandstone gradually increased, while the volume proportion of micropores (.05–100 µm) gradually decreased. With the increased freeze-thaw times, the fractal dimension of pore volume decreased from 1.94 to 1.59. The theoretical curve can better fit the characteristic points of the stress-strain curve, which can further reveal the damage mechanism of sandstone under the coupling effects of freeze-thaw and load. The minimum error between the peak point of the experimental curve and the theoretical curve is 3.3%.

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Section: Introductionmentioning

confidence: 99%

Study on the pore structure characteristics and damage constitutive model of sandstone under freeze-thaw conditions

Jin²,

Wu³

et al. 2023

Front. Earth Sci.

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“…Shields et al [22] conducted CT scans on freeze-thaw mortar samples with saturations of 75%, 90%, 95%, and 100%, finding that the crack volume increased with increases in the saturation. Song et al [23] used CT to scan sandstone samples with saturated intact, saturated fractured, and ice-filled fractured states during freezing and thawing to explore the evolution process of secondary fractures. However, most studies employing CT scans focus on freeze-thawed intact rocks with different saturations; however, since all the rocks contain defects such as cracks and joints, the fracture saturation affects the freeze-thaw damage of the rock.…”

Section: Introductionmentioning

confidence: 99%

Mesoscopic Freeze-Thaw Damage Evolution Characteristics of Fractured Sandstone at Different Saturations

et al. 2023

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To study the effect of saturation on the freeze-thaw damage of fractured rocks in cold regions, five prefabricated oval double-hole red sandstones with different saturations were prepared. Three-dimensional images of rock fractures were obtained by CT technology. The freeze-thaw damage mechanism and critical saturation of the red sandstone were explored through the fracture propagation evolution and quantitative characterization of the pore structure. The experimental results show that the pore size distribution can reflect the complex pore structure. Pores can be divided according to their sizes: small pores, mesopores, and macropores; mesopores account for the largest proportion and more than 70% of the total, and the proportion of mesopores in high-saturation sandstone (90% or 100%) increases under the action of freeze-thaw cycle. This is also accompanied by a small increase in the proportion of macropores. An 80% critical saturation of the sandstone was obtained. In addition, prefabricated cracks make the ice separation mechanism more likely to occur. The low-saturation sandstone mainly damaged the fracture area during freeze-thaw cycles, while the prefabricated cracks provided a good seepage channel for high-saturation sandstone. The corresponding rock bridge area eventually demonstrated a connectivity trend. This study more realistically reflects the freeze-thaw damage of actual rock masses in cold regions and provides a theoretical basis for the prediction of rock mass engineering disasters in cold regions.

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“…The following conditions have mainly been considered: freeze-thaw times [18][19][20], moisture content [21,22], the geometric distribution of prefabricated or natural fissures [23][24][25][26], and loading patterns, such as cyclic loading and static-dynamic loading [27][28][29][30][31]. In the test process, computed tomography scanning can be used to observe better the micropropagation law of the cracks in frozen-thawed rock [32,33]. A nuclear magnetic resonance test can be used to analyse the change of rock porosity caused by freezing-thawing and load [34,35].…”

Section: Introductionmentioning

confidence: 99%

Triaxial Compression Fracture Characteristics and Constitutive Model of Frozen–Thawed Fissured Quasi-Sandstone

et al. 2022

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The artificial frozen wall crossing the water-rich sand layer is prone to failure during thawing. To study the loading fracture characteristics and damage evolution of single-fissured sandstone after thawing, quasi-sandstones with prefabricated single fissure at different angles were prepared using the sandstone of the Luohe Formation as the original rock to conduct freeze–thaw tests with various temperature differences, and triaxial compression tests were performed on the samples. Based on the distribution theory of rock micro-element strength and static elastic modulus, a damage constitutive model of single-fissured quasi-sandstone under freezing–thawing and confining pressure was established. The results show that with the decrease in freezing temperature, the amount of flake spalling on the sample surface increases, and the frost-heaving cracks of quasi-sandstone become more numerous and longer, which makes the single-fissured quasi-sandstone tend to have a more complex tensile–shear hybrid failure than a shear failure. Moreover, with the increase in fissure angle, the absolute value of the freezing temperature required to produce frost-heaving cracks increases. An S-shaped damage evolution curve corresponds to each stage of triaxial compression of single-fissured quasi-sandstone. With the decrease in freezing temperature, the strength of rock after thawing decreases, and the brittleness characteristics strengthen.

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Fracture evolution and failure characteristics of sandstone under freeze-thaw cycling by computed tomography

Cited by 46 publications

References 36 publications

Study on the pore structure characteristics and damage constitutive model of sandstone under freeze-thaw conditions

Study on the pore structure characteristics and damage constitutive model of sandstone under freeze-thaw conditions

Mesoscopic Freeze-Thaw Damage Evolution Characteristics of Fractured Sandstone at Different Saturations

Triaxial Compression Fracture Characteristics and Constitutive Model of Frozen–Thawed Fissured Quasi-Sandstone

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