Assessment of Inherent Anisotropy and Confining Pressure Influences on Mechanical Behavior of Anisotropic Foliated Rocks Under Triaxial Compression

Fereidooni, Davood; Khanlari, Gholamreza; Heidari, Mojtaba; Sepahigero, Ali Asghar; Kolahi-Azar, Amir Pirooz

doi:10.1007/s00603-015-0814-y

Cited by 54 publications

(13 citation statements)

References 9 publications

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“…Subsequently, great efforts have been made to investigate the mechanical properties of various layered rocks by using conventional triaxial tests and other methods. Based on experimental results, there are well comprehensions of anisotropic mechanical properties under laboratory conditions for the natural layered rocks, such as shale (Donath 1961;Chenevert and Gatlin 1965;McLamore and Gray 1967;Kwaśniewski and Nguyen 1988;Niandou et al 1997;Ajalloeian and Lashkaripour 2000;Cho et al 2012;Geng et al 2016), schist (McCabe andKoerner 1975;Behrestaghi et al 1996;Nasseri et al 1997;Zhang et al 2011) and phyllite (Donath 1972;Ramamurthy 1993;Fereidooni et al 2016).…”

Section: Introductionmentioning

confidence: 99%

The anisotropic mechanical characteristics of layered rocks under numerical simulation

Zhuo

Liu

Shi

et al. 2021

J Petrol Explor Prod Technol

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Layered rocks pose the challenge of wellbore stability in drilling engineering because of the anisotropic mechanical properties caused by the distinct weak planes. To understand the significant anisotropy of layered rocks in real formation condition, true triaxial compression tests are conducted by numerical simulation in this study. It is revealed that the mechanical responses of layered rocks are either controlled by the rock matrix or dominated by the weak plane and exhibit three different types associated with the orientations of the weak plane (including the dip direction α and dip angle β). When the orientations of the weak plane are α = 0°–90° and β = 0°, 60°–90°, the failure and strength properties of layered rocks depend entirely on the rock matrix, classified to the first type. Whereas the layered rocks with angle α ≤ 45° and β = 15°–45° fail by slipping failure along the weak plane, the relationship curves of rock strength versus the intermediate principal stress (σ2) are downward convex parabolas. In the last type, the mechanical behaviors of layered rocks with α > 45° and β = 15°–45°, involved in the changes of failure mode and the strength curve, are complex. Besides, the limitation of the simulation is discussed, and further studies on layered rocks are essential.

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Section: Introductionmentioning

confidence: 99%

The anisotropic mechanical characteristics of layered rocks under numerical simulation

Zhuo

Liu

Shi

et al. 2021

J Petrol Explor Prod Technol

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“…The strength of layered rocks is closely related to not only the isotropy, but also affected by the stress state . The gained experiment results indicated that the velocity of elastic wave and mechanical parameters both changed significantly with the increase in the confining pressure . Then, several constitutive models incorporating isotropy and stress state were proposed to study the deformation and failure of layered rocks under the condition of different stress state, which could provide guidance for the engineering design.…”

Section: Introductionmentioning

confidence: 99%

“…18,19 The gained experiment results indicated that the velocity of elastic wave and mechanical parameters both changed significantly with the increase in the confining pressure. 20,21 Then, several constitutive models incorporating isotropy and stress state [22][23][24] were proposed to study the deformation and failure of layered rocks under the condition of different stress state, which could provide guidance for the engineering design. It should be pointed out that several failure criteria were proposed based on the confining pressure.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic modeling of layered rocks incorporating planes of weakness and volumetric stress

Tan

Zhou

et al. 2019

Energy Science & Engineering

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Layered rocks exhibit notable transverse isotropy and have a significant impact on the deformation and failure characteristics of underground structures. To a large extent, the mechanical properties of layered rocks are related to the structure and stress state of their bedding planes. To obtain an in‐depth understanding of the deformation and yield characteristics of layered rocks, a mechanical model for layered rocks incorporating planes of weakness and volumetric stress is proposed by improving the strain‐hardening/softening ubiquitous‐joint model based on continuum mechanics methods. In this mechanical model, elastoplastic equations for the matrix and bedding planes of layered rocks are established. The evolution of the mechanical parameters of the matrix and bedding planes of layered rocks with the internal variable is determined. In addition, the sensitivity of the model parameters is analyzed, and a method for determining the parameters is provided to reduce the complexity in obtaining these parameters. The numerical calculation results for the laboratory tests on layered sandstone specimens under various stress levels agree relatively well with the test results, thereby validating the effectiveness of the improved model. The methods and results of this study provide a significant reference for the analysis of the deformation and failure of other layered rocks.

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“…Obviously, it is inconvenient to calculate the model parameters based on the data of conventional mechanical tests. The reason lies in the fact that the values of mechanical properties will change in response to various confining pressure values [36,43,44]. This also addresses a need to develop a more efficient method to obtain mechanics parameters of rocks.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties and Statistical Damage Constitutive Model of Rock under a Coupled Chemical-Mechanical Condition

et al. 2019

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Chemical corrosion has a significant impact on the damage evolution behavior of rock. To investigate the mechanical damage evolution process of rock under a coupled chemical-mechanical (CM) condition, an improved statistical damage constitutive model was established using the Drucker-Prager (D-P) strength criterion and two-parameter Weibull distribution. The damage variable correction coefficient and chemical damage variable which was determined by porosity were also considered in the model. Moreover, a series of conventional triaxial compressive tests were carried out to investigate the mechanical properties of sandstone specimens under the effect of chemical corrosion. The relationship between rock mechanics properties and confining pressure was also explored to determine Weibull distribution parameters, including the shape parameter m and scale parameter F0. Then, the reliability of the damage constitutive model was verified based on experimental data. The results of this study are as follows: (i) the porosity of sandstone increased and the mechanical properties degraded after chemical corrosion; (ii) the relationships among the compressive strength, the peak axial strain, and confining pressures were linear, while the relationships among the elastic modulus, the residual strength, and confining pressures were exponential functions; and (iii) the improved statistical damage constitutive model was in good agreement with the testing curves with R2>0.98. It is hoped that the study can provide an alternative method to analyze the damage constitutive behavior of rock under a coupled chemical-mechanical condition.

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Assessment of Inherent Anisotropy and Confining Pressure Influences on Mechanical Behavior of Anisotropic Foliated Rocks Under Triaxial Compression

Cited by 54 publications

References 9 publications

The anisotropic mechanical characteristics of layered rocks under numerical simulation

The anisotropic mechanical characteristics of layered rocks under numerical simulation

Anisotropic modeling of layered rocks incorporating planes of weakness and volumetric stress

Mechanical Properties and Statistical Damage Constitutive Model of Rock under a Coupled Chemical-Mechanical Condition

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