Formation and fractal characteristics of main fracture surface of red sandstone under restrictive shear creep

Zhao, Hongbao; Zhang, Huan; Li, Huahua; Wang, Feihu; Zhang, Mian

doi:10.1016/j.ijrmms.2017.07.011

Cited by 32 publications

(10 citation statements)

References 5 publications

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“…e microcrack image at point E in Table 3 is imported into the ImageJ image processing program to calculate the fractal dimension, and the results are shown in Figure 6 and Table 4. It can be seen from Figure 6 that the fractal dimension of the failure surface of the models with different preexisting flaw inclination angles is different, which proves that the propensity of microcrack propagation is different, and the stress distribution and magnitude are also different [28]. As the flaw inclination increases, its fractal dimension roughly shows an increasing trend.…”

Section: Fractal Dimension Of the Microcrack Distributionmentioning

confidence: 95%

Cracking Behavior and Acoustic Emission Characteristics of Rock Containing a Single Preexisting Flaw

Luo

Lei

et al. 2021

Shock and Vibration

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The existence of flaws in brittle rocks or rock-like materials has an obvious influence on the material mechanical properties and cracking behavior of civil engineering projects. In this work, the two-dimensional particle flow code PFC2D was used to study the deformation and strength properties, failure processes, and acoustic emission (AE) characteristics of mudstone with a single preexisting flaw. First, the procedure to construct a parallel bond model is introduced. The Weibull distribution is used to reflect the mechanical heterogeneity of rocks. Then, the microscopic parameters used in PFC2D are calibrated to the macroproperties of mudstone obtained from laboratory tests under the uniaxial compression. The results indicate that the increases of the flaw inclination lead to the increasing uniaxial compressive strength and elastic modulus. In terms of microcrack evolution, the initiation, propagation, and coalescence of microcracks are closely related to the force chain. Specifically, an “X” shaped tension force chain concentrated area around the preexisting flaw is founded, which is the most prone area for microcracks to initiate. With an increase in flaw inclination, the b value of AE also shows an increasing trend. By incorporating the AE event numbers into a damage variable, this paper derives a constitutive model, which is verified by numerical results on brittle rocks with a single preexisting flaw under uniaxial compression.

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Section: Fractal Dimension Of the Microcrack Distributionmentioning

confidence: 95%

Cracking Behavior and Acoustic Emission Characteristics of Rock Containing a Single Preexisting Flaw

Luo

Lei

et al. 2021

Shock and Vibration

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“…In recent years, creep behaviour has been studied in many rocks, such as shale, 12–16 salt, 17–19 sandstone, 11,20–23 granite, 24–26 basalt, 27 tuff, 28–30 limestone, 31,32 claystone 33,34 and coal‐rock 35–37 . Although the strength parameters of different rocks are different, the characteristics of their creep curves are essentially identical for all these major types of rocks 21,38 .…”

Section: Introductionmentioning

confidence: 99%

“…Rock material (e.g., sandstone) is a kind of special porous medium with a large number of microstructures such as pores and cracks 39,40 . The existence of a large number of microstructures leads to extremely complex development and development pattern with a feature of strong non‐linearity in the process of rock failure 22 . The earlier studies showed that the creep behaviour of rock was often associated with damage 9,41 .…”

Section: Introductionmentioning

confidence: 99%

“…It can be considered as an important basis for explaining and analysing the phenomena of geological tectonic movement, as well as predicting long-term stability for rock engineering. [7][8][9][10][11] In recent years, creep behaviour has been studied in many rocks, such as shale, [12][13][14][15][16] salt, [17][18][19] sandstone, 11,[20][21][22][23] granite, [24][25][26] basalt, 27 tuff, [28][29][30] limestone, 31,32 claystone 33,34 and coal-rock. [35][36][37] Although the strength parameters of different rocks are different, the characteristics of their creep curves are essentially identical for all these major types of rocks.…”

Section: Introductionmentioning

confidence: 99%

“…39,40 The existence of a large number of microstructures leads to extremely complex development and development pattern with a feature of strong non-linearity in the process of rock failure. 22 The earlier studies showed that the creep behaviour of rock was often associated with damage. 9,41 In some rocks, cracks may not initiate and propagate at the beginning but initiate and propagate after a time-interval of sustained loading under creep condition.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Damage analysis of sandstone during the creep stage under the different levels of uniaxial stress using NMR measurements

Cheng

Zhou

Pan

et al. 2020

Fatigue Fract Eng Mat Struct

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In this paper, the nuclear magnetic resonance (NMR) measurements are carried out to evaluate the micro‐cracking characteristics of sandstones during the creep stage under the different levels of creep stresses. The variations in the parameters, including transverse relaxation time (T2) spectra distribution, percentage of the pore distribution, incremental value of porosity and ultrasonic P wave velocity are analysed. The results show that, during the creep stage, small pores in the rocks gradually evolve into large pores, resulting in an increase in damage of rocks. With the increase of the loading ratio, the increasing rate of porosity increases sharply, implying that the damage degree becomes more serious under the high loading ratio. When the loading ratio is larger than 0.7, the increasing rate of porosity and the decreasing rate of the P wave velocity both increases rapidly. During the creep stage, the relationship between micro‐crack and macro‐creep characteristics of rocks is established based on the analysis of the deformation and the porosity evolution during creep. It is found that, as the loading ratio increases, the increasing rate of porosity is linear with the creep strain. The NMR method offers a feasible option to identify micro‐cracking process of rocks during the creep stage, which can directly reflect the damage mechanism of rock caused by creep. The porosity of rocks is an effective parameter to evaluate the damage of rocks. The damage evolution of the specimen is highly anisotropic and is heavily related to the loading ratio during the creep stage. The relationship between the damage parameter and the loading ratio is exponential.

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Introduction

Zhang¹

2020

Failure Mechanism and Stability Analysis of Rock Slope

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Formation and fractal characteristics of main fracture surface of red sandstone under restrictive shear creep

Cited by 32 publications

References 5 publications

Cracking Behavior and Acoustic Emission Characteristics of Rock Containing a Single Preexisting Flaw

Cracking Behavior and Acoustic Emission Characteristics of Rock Containing a Single Preexisting Flaw

Damage analysis of sandstone during the creep stage under the different levels of uniaxial stress using NMR measurements

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