Study on Mode I–II hybrid fracture criteria for the stability analysis of sliding overhanging rock

Wu, L. Z.; Li, B.; Huang, Rui; Wang, Q.Z.

doi:10.1016/j.enggeo.2016.04.022

Cited by 26 publications

(6 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Erdogan and Sih (1963) proposed the composite criterion of minimum circumferential tensile stress (minimum tensile-stress criterion). This criterion holds that a mixed mode I-II crack propagates along the corresponding direction of minimum tensile stress satisfying the following (modified after Wu et al 2016) where IC is the corresponding direction of minimum tensile stress. The corresponding SIF of minimum tensile stress or equivalent mode I intensity factor is given by (modified after Wu et al 2016) The fracture criterion for mode I crack grow/rupture is Rao et al (2003) where K IC is the fracture toughness in mode I.…”

Section: Calculation Of K I and K Ii In Mdemmentioning

confidence: 99%

“…and is the index of the three roots and only one of them maximizes the shear stress. Therefore, the corresponding SIF of maximum shear stress or equivalent mode II intensity factor is given by (modified after Wu et al 2016) The failure criterion for shear is given by Rao et al (2003) where K IIC is the fracture toughness in mode II.…”

Section: Mixed Mode I-ii Cracks and Brittle Fracture Criterionmentioning

confidence: 99%

See 1 more Smart Citation

Fracture Assessment of Quasi-brittle Rock Simulated by Modified Discrete Element Method

Gheibi

Holt

2020

Rock Mech Rock Eng

View full text Add to dashboard Cite

New developments of an in-house hybrid code, named Modified Discrete Element Method (MDEM) are presented in the paper. The new developments are on the treatment of pre-existing and propagating fractures in quasi-brittle materials. These developments are the embedment of Linear Elastic Fracture Mechanics (LEFM) and elastic-softening crack band model-based methodologies in the MDEM and their application in lab and reservoir scale. Using the first methodology, MDEM can calculate stress intensity factors, K I and K II using the internal contact forces of particles. K I and K II are calculated independent of boundary conditions and geometrical configuration with acceptable accuracy level. The methodology has been also used in reservoir scale to study the rupture likelihood of faults and fractures due to fluid injection. This methodology enables the code to model mode I and mode II failures and propagation direction based on the fracturing model proposed by Rao et al. (Int J Rock Mech Min Sci 40(3): 355-375, 2003). Using the second methodology, the MDEM can model nonlinear behavior of quasi-brittle materials including or excluding preexisting cracks based on fracture energy. A model was verified against an experiment of a three point bend test with a notch. The numerically obtained force-crack mouth opening curve was reasonably comparable to the experimental test. The analysis was repeated for three other mesh sizes and the results are less mesh size dependent. Finally, it was shown that MDEM has the potential in studying fracture mechanics of quasi-brittle materials both in lab and large-scale investigations.

show abstract

Section: Calculation Of K I and K Ii In Mdemmentioning

confidence: 99%

Section: Mixed Mode I-ii Cracks and Brittle Fracture Criterionmentioning

confidence: 99%

Fracture Assessment of Quasi-brittle Rock Simulated by Modified Discrete Element Method

Gheibi

Holt

2020

Rock Mech Rock Eng

View full text Add to dashboard Cite

show abstract

“…The tensile strength of a rock is much smaller than its compressive strength. Hence, maximum tensile stress theory is used as the criterion for the roof fracture [20].…”

Section: Roof Fracture Criterion and Working Face Stress Statementioning

confidence: 99%

Periodic Fracture Model and Control of Hard Roof of Thin Coal Seam Short-wall Face: A Case Study of Zhuzhuang Coal Mine

Wang¹,

Shi²,

Gao³

2019

JESTR

View full text Add to dashboard Cite

The periodic fracture of the hard roof above the working face is the key influencing factor of ground pressure management in the underground exploitation of coal mines. A reasonable breaking span is greatly significant to ensure safe and efficient exploitation of coal mines. The hard roof of the short-wall working face is difficult to break during the mining process. Hence, the II646 fully mechanized coalface of the Zhuzhuang Coal Mine in a mining area in Huaibei, China was taken as the engineering background. Based on the theory of elasticity mechanics, an elastic thin-plate mechanical model of short-wall working faces was established, with the condition of two opposite edges simply supported and with one edge clamped and the other edge free (SCSF). The fracture law of hard roof was studied via theoretical analysis and onsite monitoring. Results show that the breaking span of the hard roof of the II646 working face is 80-90 m. The calculation results of the thin plate mechanical model are closer to the actual situation on-site than the calculation results of the traditional cantilever beam model. By performing calculations with maximum tensile stress theory and a bearing load capacity, the reasonable breaking span was 35 m. Based on the results of the theoretical analysis, the roof weakening scheme of the long-hole pre-splitting blasting was proposed for the II646 working face. The field practice results show that, after using deep-hole pre-splitting blasting, the periodic weighting interval and the working resistance of the support are approximately 35 m and less than 40.1 MPa, respectively. Both of these numbers indicate a decrease compared with before the roof weakens, which the periodic weighting interval (90 m) and working resistance of support (greater than 40.1 MPa), thus avoiding support collapse accidents and achieving safe and efficient mining of the short-wall working face. Such results can provide a scientific basis for the hard roof treatment of short-wall, fully mechanized working faces under similar conditions.

show abstract

“…Chen et al [9,10] determined the instability and failure mechanism of dangerous rock masses under compression-shear and tensile-shear fractures and established the calculation formula of dangerous rock stability coefficient based on fracture mechanical parameters. He et al [11] and Wu et al [12] used fracture mechanics to analyze the stress changes during the failure of tensile and shear dumping dangerous rocks and determined the influencing factors in the stability of these rocks. Appellate studies have shown that the expansion of the main joint surface of the dangerous rock mass will lead to the instability and failure of the dangerous rock mass.…”

Section: Introductionmentioning

confidence: 99%

Calculation Method of Bonding Section of Joint Surface of Dangerous Rock Mass Based on Amplitude Ratio

Hong-fei

Xie

et al. 2020

Shock and Vibration

View full text Add to dashboard Cite

In this study, through an analysis of vibration response characteristics of joint surface stiffness on dangerous rock mass, the relationship formula between amplitude ratio of the dangerous rock mass to the bedrock and the length of the bonding section of the joint surface is determined. The stability of the rock mass can be evaluated by combining the formula with the existing rock-mass limit equilibrium theory. This study proposes the existence of a resonance bonding length for the dangerous rock mass. When the length of the bonding section reaches the resonance bonding length, the dangerous rock mass has the largest response to the bedrock vibration. The study found that when the length of the bonding section of the dangerous rock mass is longer than the resonance bonding length, the amplitude ratio increases with the decrease of the bonding section and increases with the increase of the vibration frequency of the bedrock. When the length of the bonding section of the dangerous rock body is shorter than the resonance bonding length, the amplitude ratio decreases with the decrease of the bonding section and decreases with the increase of the vibration frequency of the bedrock. Indoor experiments were conducted by collecting the vibration time-history curves of rock blocks and stone piers and performing analysis and calculation, which proved the accuracy of the analytical results. Through the amplitude ratio of the dangerous rock mass and the bedrock, the bonding length can be calculated. This method can improve the calculation accuracy of the stability coefficient K of the dangerous rock mass.

show abstract

Study on Mode I–II hybrid fracture criteria for the stability analysis of sliding overhanging rock

Cited by 26 publications

References 33 publications

Fracture Assessment of Quasi-brittle Rock Simulated by Modified Discrete Element Method

Fracture Assessment of Quasi-brittle Rock Simulated by Modified Discrete Element Method

Periodic Fracture Model and Control of Hard Roof of Thin Coal Seam Short-wall Face: A Case Study of Zhuzhuang Coal Mine

Calculation Method of Bonding Section of Joint Surface of Dangerous Rock Mass Based on Amplitude Ratio

Contact Info

Product

Resources

About