Analysis of Internal Stress Distribution and Mechanics Characteristics of Pre-existing Cavity in Brittle Rock Under Triaxial Cyclic Loading

Zhou, Xiang; Li, Jiangteng; Lin, Hang

doi:10.3389/feart.2020.00033

“…Numerous studies have evaluated the mechanical responses and damage characteristics of rock masses under loading and unloading, providing important reference data (Zhao et al, 2016(Zhao et al, , 2019b. Zhou et al (2020) studied the internal stress distribution and failure characteristics of cylindrical cavities under triaxial cyclic loading and found that the number of cracks in the rock mass increased as the triaxial loading progressed, accompanied by plastic deformation. Yang et al (2009) comparatively studied salt rock deformation characteristics under uniaxial loading along with cyclic loading and unloading.…”

Section: Introductionmentioning

confidence: 99%

Study on “Triaxial Loading-Unloading-Uniaxial Loading” and Microscopic Damage Test of Sandstone

Che

¹

,

Guo

²

,

Wang

³

et al. 2020

View full text Add to dashboard Cite

To study the weakening process, deformation, and failure characteristics of rock masses surrounding deep chambers under complex stress environments, triaxial loading tests along with triaxial loading/unloading followed by uniaxial loading tests were conducted on sandstone specimens. The internal microcracks of the specimens under the loading and unloading of triaxial confining pressure were observed by scanning electron microscopy. The results revealed the inherent mechanism of plastic deformation (irreversible deformation) of the rock mass under different confining pressures. Under uniaxial loading and triaxial loading, the sandstone specimens exhibited X-shaped shear failure and single shear failure, respectively. In contrast, the sandstone samples subjected to the loading and unloading of triaxial confining pressure followed by uniaxial loading showed multiple shear fracture surfaces and fine fissures along the axial direction. A larger initial axial pressure of the sandstone specimen corresponded to a smaller uniaxial loading strength after unloading the confining pressure, a greater amount of plastic deformation, more macro-and microfissures, and more severe damage to the specimen. These results show that the final failure mode, strength, degree of damage, and plastic deformation of sandstone specimens are related to the stress state at the time of failure along with the loading history before failure.

show abstract

“…e numerical model is composed of homogeneous particles which are linked by parallel bonding [43][44][45][46]. In the parallel bond contact model, the bond is equivalent to a number of springs acting side by side, which can transmit both force and torque and which is more in line with the mechanical properties of rock materials, and it is the most widely used model to simulate the mechanical properties of the rock.…”

Section: Numerical Modelmentioning

confidence: 99%

Shear Failure of Bolted Joints considering Mesoscopic Deformation Characteristics of Rock

Cheng

¹

,

He

²

,

Yang

³

2020

Advances in Civil Engineering

0

View full text Add to dashboard Cite

In rock engineering of the cold region, there are a lot of rock joints. The shear characteristics of joints play a decisive role in the stability of rock engineering in the cold area. In this paper, based on the numerical simulation method of particle flow, reasonable microscopic parameters are selected for the numerical simulation of the direct shear test of bolted joints. The results show that the shear stiffness and contact modulus are linearly and positively correlated. The greater the contact modulus, the greater the residual stress, the better the synergetic effect between rock and bolt, and the more developed the microcrack. The smaller the contact stiffness ratio, the greater the residual stress. The shear stiffness decreases with the increase in the contact stiffness ratio, and the larger the contact stiffness ratio, the slower the shear stiffness decreases, while the shear strength does not change with the contact stiffness ratio. The contact stiffness ratio has a weak effect on the number of cracks in the model. The shear stiffness increases with the increase in the parallel bond modulus, and the shear strength decreases with the increase in the parallel bond modulus. The binding stiffness is independent of the shear stiffness, and the peak shear stress decreases with the increase in the binding stiffness ratio. The greater the bond stiffness ratio, the greater the number of cracks.

show abstract

“…At present, the researches on anisotropic rock properties are mainly concentrated on the following areas: (1) the measurement method study of elastic deformation parameters [2], (2) the anisotropy strength and yield criterion study [3,4], (3) anisotropic rock constitutive model study [5,6], and (4) anisotropic rock deformation characteristics and mechanical property study [7,8]. Transverse isotropy is a special case of anisotropy; these studies have a great significance on helping us have a better understanding of the permeability and mechanical properties of transversely isotropic rocks.…”

Section: Introductionmentioning

confidence: 99%

Related Rule Study of Subcritical Crack Growth and Threshold Values in Transversely Isotropic Slates

Ma

¹

,

Li

²

,

Wang

³

2020

Geofluids

Self Cite

2

0

View full text Add to dashboard Cite

Elastic parameters and the subcritical crack growth of different bedding angle slate specimens were studied using uniaxial compression testing and the double torsion constant displacement load relaxation method using SANS and MTS Insight machines. To study the relations of the mode-I stress intensity factor K I versus the subcritical crack growth velocity V , the fracture toughness K I C , the stagnation speed, and the threshold values, the double torsion constant displacement load relaxation method was carried out. The related rules between the bedding angles (β) and the uniaxial compressive strength, fracture toughness, and threshold values were investigated. Experimental results show that the uniaxial compression, the fracture toughness, and the threshold value curves move to the bottom then increase with the increase of the β angle. In addition, its fracture toughness is minimal when the β angle of the slates is 45°, and crack initiation and crack propagation are generated under load, which can lead to the failure of the slate. lg K I - lg V relations of transversely isotropic slates measured by this method are in accordance with linear rules, which is in good agreement with the Charles theory. The range of K 0 / K I C for these different bedding angle slates is from 0.511 to 0.789. The test results would provide the basis for studying seepage and time-dependency of rock engineering stability.

show abstract

Analysis of Internal Stress Distribution and Mechanics Characteristics of Pre-existing Cavity in Brittle Rock Under Triaxial Cyclic Loading

Cited by 6 publications

References 33 publications

Study on “Triaxial Loading-Unloading-Uniaxial Loading” and Microscopic Damage Test of Sandstone

Study on “Triaxial Loading-Unloading-Uniaxial Loading” and Microscopic Damage Test of Sandstone

Shear Failure of Bolted Joints considering Mesoscopic Deformation Characteristics of Rock

Related Rule Study of Subcritical Crack Growth and Threshold Values in Transversely Isotropic Slates

Contact Info

Product

Resources

About