The Effects of Precrack Angle on the Strength and Failure Characteristics of Sandstone under Uniaxial Compression

Zhang, Shuai; Xu, Jinhai; Chen, Liang; Shimada, Hideki; Zhang, Mingwei; He, Haiyang

doi:10.1155/2021/7153015

Cited by 2 publications

(2 citation statements)

References 34 publications

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Section: Udec T-w Modeling Methodsmentioning

confidence: 99%

“…Therefore, in addition to the mechanical properties of the Trigon blocks, the micro-properties of the contact elements should also be determined. In fact, the process of calibrating the micro-properties of the contact elements through the macro mechanical properties of hydrostone is a trial-and-error process, which follows the following procedures [27,34]: (1) adjust the shear stiffness and the normal stiffness of the contact elements until the Young's modulus calculated by uniaxial compression test simulation matches the Young's modulus of the rock according to the shear stiffness to normal stiffness ratio (k s /k n ) equals the shear modulus to Young's modulus ratio of the rock; (2) simulate the Brazilian tests with different contact tensile strengths until the simulation result matches the tensile strength of the rock; (3) adjust contact cohesion C cont and contact friction angle ϕ cont , and conduct a series of confined compression test simulations for each group of contact cohesion and contact friction angle. For each series of simulation results, the confining pressure-confined compressive strength curve can be fitted.…”

Section: 𝜑 = 𝑎𝑟𝑐𝑠𝑖𝑛mentioning

confidence: 99%

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Numerical Investigation of Influence of Fluid Rate, Fluid Viscosity, Perforation Angle and NF on HF Re-Orientation in Heterogeneous Rocks Using UDEC T-W Method

Zhang

Chen

et al. 2022

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Numerical simulation is very useful for understanding the hydraulic fracture (HF) re-orientation mechanism from artificial weaknesses. In this paper, the UDEC T-W (Trigon–Weibull distribution) modeling method is adopted to simulate the hydraulic fracturing process in heterogeneous rocks. First, the reliability of this method is validated against previous laboratory experiments and numerical simulations. Then the effects of fluid rate, fluid viscosity, perforation angle and natural fracture (NF) on the HF re-orientation process in heterogeneous rocks are studied independently. The results show that the HF re-orientation process depends on the combined effect of these factors. The HF re-orientation distance increases significantly, the final HF re-orientation trajectory becomes more complex and the guiding effect of perforation on the HF propagation path is more evident with the increase of fluid rate, fluid viscosity, and perforation angle if the hydraulic fracturing is performed in relatively heterogeneous rocks, while the differential stress is the main influencing factor and is more likely to dictate the HF propagation path if the rocks become relatively homogeneous. However, increasing the fluid viscosity and fluid rate can attenuate the impact of differential stress and can promote HF propagation along the perforation direction. Besides, NFs are also the important factor affecting HF re-orientation and induce secondary HF re-orientation in some cases in heterogeneous rocks.

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Section: Udec T-w Modeling Methodsmentioning

confidence: 99%

Section: 𝜑 = 𝑎𝑟𝑐𝑠𝑖𝑛mentioning

confidence: 99%

Numerical Investigation of Influence of Fluid Rate, Fluid Viscosity, Perforation Angle and NF on HF Re-Orientation in Heterogeneous Rocks Using UDEC T-W Method

Zhang

Chen

et al. 2022

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Study on Mechanical Properties and Damage Constitutive Model of Rock Mass with Different Fracture Lengths

Zhang

Chen

Che

et al. 2023

Journal of Testing and Evaluation

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This article, on the basis of experimental research, combines theoretical analysis and numerical calculation. In addition, the research, while taking into consideration different fracture lengths, confining pressure of rock mass mechanics properties, and behavior of evolution law, establishes and reflects the unique characteristics of the processes of fractured rock mass deformation and destruction of the damage constitutive model. In this instance, the discrete element method numerical has been discussed from the perspective of mesoscopic fracture mechanism of the fractured rock mass. The results show that the capacity of resistance of rock mass deformation and destruction along with the increase of fracture length, the peak stress of rock mass, the elastic modulus, and peak strain are positively correlated with the confining pressure. Furthermore, an increase in the confining pressure, transition of rock mass from brittle to ductile, an intact sample to shear failure pattern by stretching evolution, and different fracture lengths are characterized by shear failure form. Based on the statistical damage theory and Drucker Prager yield criterion, the damage constitutive model of fractured rock mass has been determined, and the physical meaning of the model parameters has been clarified through experimental analysis. The strength characteristics and damage evolution law of fractured rock mass revealed by the damage constitutive model are consistent with the test results, thereby verifying the rationality of the model. According to the numerical simulation of the evolution characteristics of the number of microcracks, the failure process of rock mass can be divided into four stages, namely crack initiation stage, crack steady growth stage, pre-peak crack accelerated growth stage, and post-peak crack accelerated growth stage. The simulation results of the deformation failure process and model are basically the same as those of the laboratory experiment. The theoretical results are expected to provide an important theoretical foundation for theoretical research of rock mass mechanics and engineering stability evaluation.

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The Effects of Precrack Angle on the Strength and Failure Characteristics of Sandstone under Uniaxial Compression

Cited by 2 publications

References 34 publications

Numerical Investigation of Influence of Fluid Rate, Fluid Viscosity, Perforation Angle and NF on HF Re-Orientation in Heterogeneous Rocks Using UDEC T-W Method

Numerical Investigation of Influence of Fluid Rate, Fluid Viscosity, Perforation Angle and NF on HF Re-Orientation in Heterogeneous Rocks Using UDEC T-W Method

Study on Mechanical Properties and Damage Constitutive Model of Rock Mass with Different Fracture Lengths

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