Damage characteristics of sandstone with different crack angles subjected to true triaxial cyclic loading and unloading

Hu, Huarui; Lu, Yiyu; Xia, Binwei; Luo, Yafei; Peng, Jinrong; Li, Yang

doi:10.1016/j.tafmec.2022.103444

Cited by 19 publications

(7 citation statements)

References 41 publications

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“…The fracture index deformation equation , can describe changes in the dynamic behavior of fracture width better than the linear deformation equation. w normalh = w 0 e − β false( δ n − P false) / 3 where w 0 is the fracture static width, m; β is the fracture index deformation, Pa –1 ; P is the intraseam pressure, Pa; and P 0 is the formation pore pressure, MPa.…”

Section: Fracture Characterizationmentioning

confidence: 99%

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Study on the Model and Law for Radial Leakage of Drilling Fluid in Fractured Formations

Zhang

Zhou

et al. 2022

ACS Omega

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The economic loss caused by fracture leakage accounts for 90% of all leakage costs; thus, it is necessary to find the factors that affect the leakage and to study the leakage laws of fractured strata. The advantage of this article is that we introduced fracture index deformation and fracture tortuosity parameters to characterize fracture roughness and fracture characteristic parameters using the logging data analysis method. To explore the mechanism of leakage in essence, this paper, based on fluid mechanics, improves the radial leakage model by adopting the Herschel–Bulkey (H–B) flow type drilling fluid with high calculation accuracy and comprehensively considering the factors such as drilling fluid performance parameters, fracture roughness characteristic parameters, pressure difference between the wellbore and formation, and radial extension length of the drilling fluid. The advantage of the model is that it is solved in an absolutely stable backward Euler difference format. The numerical simulation is carried out by MATLAB. The simulation results revealed that the leakage rate increased as the fracture index deformation coefficient and the fracture opening increased. The leakage rate also increased as the fracture tortuosity parameters decreased and as the fracture smoothened. However, the leakage rate decreased as the drilling fluid consistency coefficient increased. Drilling fluid dynamic shear force had a minor effect on the leakage rate. The higher the pressure difference between the wellbore and the formation, the higher the leakage rate. As the drilling fluid intrusion depth increased, the leakage rate decreased until it reached 0. Two parameters were mainly controlled in order to control the degree of leakage: differential pressure and fracture static width, which has important guiding for adjusting the drilling fluid density and predicting leaks in the field. The solution method of the model in this paper has a certain reference value for the solution of other models in the future. The conclusion can provide reference for numerical simulation, laboratory test, and field application in the future.

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Section: Fracture Characterizationmentioning

confidence: 99%

“…The fracture index deformation equation 30,31 can describe changes in the dynamic behavior of fracture width better than the linear deformation equation.…”

Section: Fracture Characterizationmentioning

confidence: 99%

Study on the Model and Law for Radial Leakage of Drilling Fluid in Fractured Formations

Zhang

Zhou

et al. 2022

ACS Omega

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“…At present, scholars at home and abroad have systematically studied the infuence of crack dip angle, number and length on the strength, and deformation and failure characteristics of coal mass through laboratory tests and numerical simulation [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Burst Failure Characteristics and Energy Evolution Law of Coal with Prefabricated Cracks at Different Angles

Zhang,

Han,

Chen

et al. 2024

Shock and Vibration

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In order to study the influence of fissures on the burst tendency of coal, the test and numerical simulation of the burst tendency of coal with different burst angles were carried out. The evolution law of the burst tendency index of coal under the influence of burst angle was analyzed, and the mechanism of energy storage and release of coal under the influence of fissure angle was revealed. The results show that compared with the specimens without prefabricated cracks, the uniaxial compressive strength of the specimens with 0° cracks is reduced by 48.4%, the dynamic failure time is increased by 279.4%, the burst energy index is reduced by 54%, and the burst energy velocity index is reduced by 87.9%. After that, with the increase of prefabricated crack angle, the uniaxial compressive strength of coal increases gradually, the dynamic failure time decreases gradually, the burst energy index increases gradually, and the burst energy velocity index increases gradually. That is to say, the larger the crack angle contained in the coal body, the stronger the burst tendency of the coal body, but it is still lower than that of the complete coal body. With the increase of prefabricated crack angle, the proportion of prepeak elastic energy of coal body increases, the less energy dissipation in the whole loading process of coal body, and the faster energy release rate during failure. The research results can provide some theoretical support for the prevention and control of rock burst disaster.

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“…Xiao et al [ 22 ] studied the influence of prior cyclic loading and unloading damage on subsequent unloading behavior of sandstone under true triaxial conditions, and analyzed the influence law of cyclic loading and unloading times on strength and deformation characteristics, energy conversion and failure mode of sandstone. Hu et al [ 23 , 24 , 25 ] carried out true triaxial cyclic loading and unloading tests on fractured sandstone samples and analyzed the evolution laws of sandstone strength, deformation and energy. Meanwhile, they defined damage variables based on plastic deformation and energy dissipation and obtained the damage laws of fractured sandstone.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Mechanical and Damage Evolution Characteristics of Coal during True Triaxial Cyclic Loading and Unloading

et al. 2023

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Research on the mechanical properties and damage evolution of coal during true triaxial cyclic loading and unloading is of great significance for maintaining the long-term safety and stability of underground engineering structures in coal mines. In this paper, firstly, the deformation, strength and fracturing characteristics of coal during true triaxial loading and true triaxial cyclic loading and unloading were analyzed. Then, the residual strain characteristics, energy distribution and evolution of coal were systematically studied. Additionally, the damage evolution laws of coal during cyclic loading and unloading were quantitatively analyzed from the perspectives of residual strain and energy dissipation, respectively. The damage evolution law based on residual strain showed that when the intermediate principal stress was high, the damage to coal was directional. With the increase in cyclic load, the coal damage variables in the directions of σ1 and σ3 increased exponentially, while that in the direction of σ2 increased quadratically. The damage evolution law based on energy dissipation showed that the coal damage variable increased exponentially with the increase in cyclic load. With the increase in σ2, the increasing speed of coal damage variable decreased first and then increased. The damage variables established based on residual strain and energy dissipation can both reveal the damage deterioration mechanism of coal during true triaxial cyclic loading and unloading, which is of great theoretical and engineering significance for scientifically evaluating the stability of underground coal and rock engineering and preventing the occurrence of major geological disasters.

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Damage characteristics of sandstone with different crack angles subjected to true triaxial cyclic loading and unloading

Cited by 19 publications

References 41 publications

Study on the Model and Law for Radial Leakage of Drilling Fluid in Fractured Formations

Study on the Model and Law for Radial Leakage of Drilling Fluid in Fractured Formations

Burst Failure Characteristics and Energy Evolution Law of Coal with Prefabricated Cracks at Different Angles

Experimental Study on Mechanical and Damage Evolution Characteristics of Coal during True Triaxial Cyclic Loading and Unloading

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