Stable Crack Propagation Model of Rock Based on Crack Strain

Huang, Xiao Fei; Shi, Chong; Ruan, Huaining; Zhang, Yiping; Zhao, Wei

doi:10.3390/en15051885

Cited by 17 publications

(12 citation statements)

References 34 publications

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“…Logistic regression algorithm mainly through the sigmoid function to deal with data sets into a binary classification problem. The sigmoid function is shown in (5).…”

Section: Improved Logistic Regression Algorithmmentioning

confidence: 99%

“…At present, a large number of studies on fractured rock have been carried out at home and abroad 2,3 , mainly including strength analysis strength prediction model and fracture diffusion mechanism [4][5][6] . In the analytical solution based on rock strength theory, Xinxi, L et al improved the Drucker-Prager criterion based on the influence of dry-wet cycles and fracture dip on shale strength 7 .…”

Section: Introductionmentioning

confidence: 99%

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Strength prediction model of fractured dolomite and analysis of mechanical properties based on PFC3D

Chen

Rao

Zhao

et al. 2023

Preprint

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In order to study the mechanical properties of fractured dolomite, this paper first uses the rubbing method to count the surface fracture of the dolomite rock samples, obtains the main parameters of the fracture characteristics, and then carries out the uniaxial compression test to obtain the uniaxial compressive strength of the dolomite rock. Then, the Pearson correlation coefficient and the maximum information coefficient (MIC) are used to analyze the fracture characteristics. The three-times polynomial is used to preprocess the original data, and the three-classification strategy is used to improve the logistic regression algorithm to predict the dolomite strength. Finally, the significant order of the influence of fracture characteristics on rock strength is judged by numerical simulation software PFC3D, and the dip angle effect of rock fracture is explained from the perspective of fracture propagation. The results show that: 1) When the regularization coefficient λ = 10000, the algorithm has the highest prediction accuracy and the strongest model generalization ability. 2) The numerical simulation analysis software PFC3D can accurately invert rock failure process and characteristics, and the order of influence of fracture characteristics on rock strength is inclination > length > position. 3) When α = 0° ~ 90°, the peak strength decreases first and then increases. The greater the peak strength of the rock, the more obvious the crushing phenomenon, and the worse the wing fracture expansion ability. When α = 60°, the peak strength is the lowest.

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“…Logistic regression algorithm mainly through the sigmoid function to deal with data sets into a binary classification problem. The sigmoid function is shown in (5).…”

Section: Improved Logistic Regression Algorithmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Strength prediction model of fractured dolomite and analysis of mechanical properties based on PFC3D

Chen

Rao

Zhao

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Hence, it is possible to obtain the rock’s mechanical, deformational, AE, failure, and energy properties, and so on. In addition, the effects of different crack combinations, water, heat, chemistry, and other environments on it are studied, and many useful results are obtained [ 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. However, most of the defects in these studies are concentrated in the middle of the rock specimen or symmetrically distributed in the middle of the rock, and there are also a few studies on the distribution of shear cracks and tensile cracks in rock failure.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Microcrack Evolution Characteristics of Roof Rock of Coal Seam with Different Angle of Defects Based on Particle Flow Code

et al. 2023

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The creation of the natural ceiling rock of the coal seam is rife with fractures, holes, and other flaws. The angle of the defects has a significant influence on the mechanical characteristics and crack evolution of coal seam roof rock. Multi-scale numerical simulation software PFC2D gets adapted to realize the crack propagation and coalescence process in the roof rock of a coal seam with different angles of defects under uniaxial compression. The effect of flaw angles on the micro and macro mechanical characteristics of rock is also discovered. The results show that: (1) the defect angle has influence on the stress-strain, elastic modulus, peak strength, peak strain, acoustic emission (AE) and strain energy of roof rock of coal seam. When the defect angles are different, the starting position of the roof rock in a coal seam fracture is different. The quantity of microcracks firstly reduces with an increase in defect angles before gradually increasing. At the same fault angle, the cracks are mostly tensile ones and only a few shear ones. (2) When the defect angle is less than 90°, tensile and shear fractures are mostly localized at the defect’s two tips and propagate along the loading direction. When the defect angle is 90°, the tensile and shear cracks are not concentrated at the tip of the defect. (3) As the defect angles increase, the elastic strain energy rises initially and then falls, and the dissipated energy and total input energy both increase continuously. The elastic strain energy is greatest at the highest strength. The study provides a certain reference for the use of various analysis methods in practical engineering to evaluate the safety and stability of rock samples with pre-existing defects.

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“…However, the randomness and uncertainty in the geometry, distribution and evolution of microcracks makes it difficult to clearly determine the microcrack evolution patterns. The use of the proposed crack strain (Martin, 1993) effectively avoids the difficulty of studying microcrack evolution (Huang et al, 2022). Therefore, the study of rock fracture evolution characteristics from the perspective of crack strain can provide a deep understanding of the time-dependent evolution of rock.…”

Section: Introductionmentioning

confidence: 99%

Creep crack energy dissipation and instability prediction in micritic bioclastic limestone

Li²,

Yao³

et al. 2023

Front. Earth Sci.

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Time-dependent deformation and long-term stability of rocks are important issues in water conservancy and geotechnical engineering. Currently, there are no well-accepted theoretical criteria with which to predict stability and damage considering time-dependent deformation. In-depth research is still needed. Multilevel creep experiments were performed on micritic bioclastic limestone obtained from a continuously deforming tunnel in Xinjiang, China. Based on crack strain theory, the axial crack strain evolution characteristics during loading and creep processes were investigated. The evolutionary characteristics of the crack dissipation energy density, which was obtained via integration of the crack strain during loading and creep, were revealed. The energy dissipation leading to rock fracture in each multilevel creep experiment was identified and used to calculate the total energy dissipated at the point at which the rock loses strength. A rock instability index based on the creep crack dissipation energy density was proposed. An instability index evolution model was proposed, expressed as a surface for the change in instability index with the bearing state (Rd) and time. Based on the instability index surface, the stress threshold creep-sensitive stress σcs was defined. The time-dependent instability index surface was divided into a long-term stability zone (Z1), an initial time-dependent instability zone (Z2), a time-dependent instability stable evolution zone (Z3) and a time-dependent instability sensitive zone (Z4) by the crack initial stress, crack damage stress, and creep sensitive stress. The instability index model was established as an energy instability evolution criterion to evaluate and predict the rock instability and lifespan under specific stress states.

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Stable Crack Propagation Model of Rock Based on Crack Strain

Cited by 17 publications

References 34 publications

Strength prediction model of fractured dolomite and analysis of mechanical properties based on PFC3D

Strength prediction model of fractured dolomite and analysis of mechanical properties based on PFC3D

Mechanical and Microcrack Evolution Characteristics of Roof Rock of Coal Seam with Different Angle of Defects Based on Particle Flow Code

Creep crack energy dissipation and instability prediction in micritic bioclastic limestone

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