Effect of crack interaction and friction on the dynamic strength of rock-like materials with many cracks

Qi, Chengzhi; Chen, Xia; Dyskin, Arcady; Zhao, Fa Suo

doi:10.1016/j.engfracmech.2021.108006

Cited by 6 publications

(2 citation statements)

References 53 publications

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“…Chen et al [ 37 ] found that the stress intensity factors of type I and type II cracks had a certain influence on the crack propagation trajectory, and the change of the stress field at the crack tip was the main factor in crack propagation. Qi et al [ 38 ] believed that the interaction between cracks was related to the density of crack distribution. The greater the density, the stronger the interaction between them, and the lower the strength of rock failure.…”

Section: Resultsmentioning

confidence: 99%

Energy evolution and crack development characteristics of sandstone under freeze-thaw cycles by digital image correlation

Jin

Feng

et al. 2023

PLoS ONE

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Freeze-thaw erosion is the main reason for rock mass instability in cold regions and poses major threats to public safety. In this study, the stress threshold, energy, and strain field evolution of sandstone and the variation in stress intensity factor of fractures in various stress fields were all investigated after freeze-thaw cycles by uniaxial compression tests and digital image correlation technology. The results show that the elastic modulus, crack initiation stress, and peak stress all fell by 97%, 92.5%, and 89.9%, respectively, as the number of freeze-thaw cycles approaches 80. Elastic energy’s storage capacity also dropped from 0.85 to 0.17. Sandstone’s strain was increased by freeze-thaw erosion, which also improved ductility and shortened the cracking time. The stress intensity factor at the crack tip was positively correlated with the tip inclination angle and negatively correlated with the number of freeze-thaw cycles. This study provides a useful reference for understanding the stability of rock masses and the characteristics of crack derivation in cold regions.

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Section: Resultsmentioning

confidence: 99%

Energy evolution and crack development characteristics of sandstone under freeze-thaw cycles by digital image correlation

Jin

Feng

et al. 2023

PLoS ONE

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“…Актуальность темы оценки параметров трещинной пустотности горных пород вытекает из необходимости решения задач прочности [1][2][3][4], устойчивости пород вокруг горных выработок [5][6][7], гидроразрыва породных массивов [8][9][10], фильтрации флюида через массив [11,12], расчета параметров бурения и взрыва [13][14][15], а также из других практических задач горного производства. Для определения трещиноватости используют геологические [16][17][18], маркшейдер-ские [19-21], видеометоды [22,23].…”

Section: Introductionunclassified

Influence of random parameter joint length on rock electrical conductivity

Sizin

Вознесенский

Kidima-Mbombi

2023

Min.Sci.Technol. (RUS)

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Rock joint hollowness coefficient is an important parameter when resolving practical mining problems. Geophysical methods used to resolve this problem are indirect. Thus the interpretation of their results may cause certain difficulties as a result of the uncertainty of the physical relationships between the parameters of joints and the measurement results. One of the ways to resolve this problem is to combine experimental research methods with analytical and numerical simulation. The studies were aimed at investigating the electrical conductivity of a two-dimensional medium in the presence of thin insulating (non-conducting) joints. This paper proposes an analytical method for assessing the dependence of the specific conductivity of a medium with inclusions in the form of elliptical joints on their half-length. This dependence is show to have the form of an exponent depending on the square of the length of the maximum semi-axis as an argument. The simulation method is based on the assumption of the elliptical shape of a joint when the length of the minor semi-axis of the ellipses tends to zero. A review of publications and their results presented in this paper showed that this method for determining the specific conductivity of the medium with thin joints is one of the best in terms of compliance with experimental data. Its predictions are close to those of the Effective Media Approximation (EMA). However, the proposed method is distinguished by the simplicity of the formulas and their physical visibility essential for the use in interpreting the data of a physical experiment. In two-dimensional formulation, numerical simulation of the specific electrical conductivity of a sample of a medium measuring 1×1 m with elliptical joints of conductivity less than that of the matrix was carried out in the COMSOL Multiphysics environment. A square sample of unit sizes with unit conductivity was considered in which 25 joints with uniform distribution along the length occurred. 40 models were built wherein the maximum length of the joints varied from 0.01 to 0.4 sample size in increments of 0.01 m. The satisfactory concordance of the results of numerical and analytical models, both visual and confirmed by statistical estimates, has been shown. It was noted that when the size of the joints changes to achieve the value of the maximum semi-axis α = 0.15 m, the influence of single joints that do not extend beyond the boundaries of the sample prevails. Above this value, at α > of 0.15 m, the influence of joint coalescence, as well as their extension to and beyond the sample boundaries begins to affect. Comparison of the proposed theoretical model of electrical conductivity, depending on the square of the length of the maximum semi-axis of a joint, with a similar model in the form of an exponent with a linear dependence showed a better concordance of the proposed model with observations at the stage of the lack of joint coalescence and their extension to the sample boundaries at α < 0.15 m. At α > 0.15 m. The proposed model has a lower coefficient of determination compared to the full range including both intervals, but higher than that of the model with a linear dependence in the exponent argument. This indicates the universal nature of the proposed model.

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Dynamic mechanical response characteristics and cracking behavior of randomly distributed cracked sandstone

Yuan

Zhang

et al. 2023

Comp. Part. Mech.

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Effect of crack interaction and friction on the dynamic strength of rock-like materials with many cracks

Cited by 6 publications

References 53 publications

Energy evolution and crack development characteristics of sandstone under freeze-thaw cycles by digital image correlation

Energy evolution and crack development characteristics of sandstone under freeze-thaw cycles by digital image correlation

Influence of random parameter joint length on rock electrical conductivity

Dynamic mechanical response characteristics and cracking behavior of randomly distributed cracked sandstone

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