Physical and numerical study of strain burst of mine pillars

Fakhimi, A.; Hosseini, Omid; Roosevelt, Theodore

doi:10.1016/j.compgeo.2015.12.018

Cited by 51 publications

(13 citation statements)

References 16 publications

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“…These dynamic disasters caused huge economic loss and causalities. Accordingly, the prevention and control of dynamic disaster in coal-rock system has been a hot research issue (Fakhimi et al 2016;Wu et al 2020;Wang et al 2020).…”

Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Experimental Study on the Law of Energy Dissipation and Damage in Coal Body Based on Local Tensile-Sliding Effect

Yi-shan

2021

Preprint

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The slippage initiation and induced instability of roadway surrounding rock are highly likely to cause dynamic disasters, severely influencing the safety production of mining. With the optical-mechanical monitoring test of the deformation localization of energy dissipation, this study established the optical index of coal deformation equilibrium degree under load, and obtained the evolution law of coal deformation equilibrium degree. After analyzing the relationship between tensile-sliding effect and mechanical behavior of coal deformation field, it proposed the strain energy ratio coefficient. The results indicate that the strength reduction of coal body is affected by the deformation accumulation of loading displacement field. The sliding displacement of the stable sliding type specimen occurs 5.5s earlier than tensile displacement，which is 4.4s longer than the instantaneous instability type specimen. The instability type of coal is closely related to the tangent angle of the strain energy ratio coefficient and the damage persistence characteristics. The damage accumulation of stable equal amplitude contributes to the stable failure, and the damage accumulation of interval equal amplitude influences the instantaneous instability development. The fracture expansion stage is the main stage of energy consumption damage accumulation. That is, the main energy consumption damage accumulation stage of the stable slip coal is the stable crack expansion stage, with the damage proportion of 35.89%, while the damage proportion of instantaneous instability coal in the unsteady crack expansion stage is 84.226%. The study provides theoretical reference for the fracture law and risk monitoring of coal slippage.

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Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Experimental Study on the Law of Energy Dissipation and Damage in Coal Body Based on Local Tensile-Sliding Effect

Yi-shan

2021

Preprint

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“…Manouchehrian and Cai proposed to use the transferred energy ratio and loading system reaction intensity as indicators to distinguish between stable and unstable failures in a UCS test (Manouchehrian and Cai 2015). Fakhimi et al found that the rock specimen's diameter and strength had large impact on the ejected velocity of rock fragments, and weakening of the rock by drilling holes in it could reduce the violence of rock failure in numerical models (Fakhimi et al 2016). Poeck (Poeck 2017) simulated two pillar burst events with mine-scale numerical models based on actual mine cases, and compared the released energy and ground subsidence from numerical models with field monitored data to evaluate the reliability of the numerical results.…”

Section: Numerical Simulation Of Laboratory Rock Failures and Mine-scale Rockbursts Have Been Commonlymentioning

confidence: 99%

“…Various laboratory-based experiments have been conducted to analyze the underlying mechanisms of unstable rock failure (Wawersik and Fairhurst 1970;Singh 1987Singh , 1988Zhao and Cai 2014;Heinze et al 2015;He et al 2016a;Kim and Larson 2017;Leveille et al 2017). To study pillar bursting in the laboratory, Fakhimi et al designed a steel beam to act as an energy absorber, which was placed between the loading platen and rock specimen (Fakhimi et al 2016). The stored elastic strain energy in the steel beam could fail the sandstone samples violently, and a maximum rock fragment velocity of over 4 m/s was identified using a high-speed camera.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Unstable Rock Failure Mechanisms Through Analysis of Energy Transformations

Kaunda

Wang

2021

Preprint

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For rock specimen in uniaxial compression, the energy transformations from elastic strain energy in both the rock and the loading system to plastic strain work in the rock can be identified with the changes in these energy components, whose rates are also useful indicators for distinguishing stable and unstable rock failure. In this study, the influences of the loading system stiffness (LSS), the rock stiffness and the rock brittleness on rock failure modes are examined. The observed energy transformations during rock failure in numerical models are interpreted from an energy perspective. The results show that unstable rock failure tends to occur in rock with large brittleness and small stiffness under a soft loading system. A low LSS and rock stiffness will increase the magnitude of stored elastic strain energy before rock failure, while a brittle rock requires less elastic strain energy to be converted plastic strain work than a ductile rock during its failure. This energy-based approach is useful for investigating potential unstable rock failures that could ultimately be applied to analyze complex mine-scale rockburst cases.

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“…30 The physical similar experiment is a laboratory research method based on similarity theory and dimensional analysis, currently widely used in mining, geology, and other engineering fields. [31][32][33] It is convenient to visually observe the changes in stress, displacement, failure, and motion of the analog strata under the mining actions. The nephograms such as displacement and deformation of model strata can be obtained using a digital image correlation (DIC) method.…”

Section: Introductionmentioning

confidence: 99%

Physical simulation of upper protective coal layer mining with different coal seam inclinations

Fang

Shu

Wang

2020

Energy Science & Engineering

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Protective coal layer (PCL) mining is a preferred regional method for preventing coal and gas outbursts; stress‐relief of PCL mining is the prerequisite of pressure‐relief gas drainage. In order to study the stress‐relief effect of PCL mining on protected coal seams and determine the protection scope of PCL mining under different inclinations, this paper uses physical simulations to study the stress‐relief law and deformation characteristics of the strata during upper PCL mining with a gentle inclination (25°), an intermediate inclination (45°), and a steep inclination (65°). The results show that as the coal seam dip increases, the degree of deformation and failure of the overburden strata gradually decreases, the severe subsidence and expansion area of the overburden strata tends to gradually develop in the uphill direction of the working face, and the floor strata underlying the protective seam significantly expand toward the goaf. However, the absolute value of the upward movement of the floor strata is much smaller than that of the roof strata; and the greater the dip angle, the greater the ratio of floor displacement to roof subsidence. The stress‐relief curve of the protected layer is approximately U‐shaped. As the inclination of the coal seam increases, the stress‐relief range decreases gradually. The maximum relief‐stress and the stress release coefficient of the protected layer initially increase and then decrease. The stress concentration coefficient of the protected coal seam initially increases first and then decreases in both uphill and downhill of the working face in the PCL. As the inclination increases, the stress‐relief angle of the downhill boundary initially increases and then decreases, while the stress‐relief angle of the uphill boundary decreases gradually. Our research results provide guidance for the delimitation of the protected scope of PCLs with different dip angles.

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Physical and numerical study of strain burst of mine pillars

Cited by 51 publications

References 16 publications

WITHDRAWN: Experimental Study on the Law of Energy Dissipation and Damage in Coal Body Based on Local Tensile-Sliding Effect

WITHDRAWN: Experimental Study on the Law of Energy Dissipation and Damage in Coal Body Based on Local Tensile-Sliding Effect

Numerical Simulation of Unstable Rock Failure Mechanisms Through Analysis of Energy Transformations

Physical simulation of upper protective coal layer mining with different coal seam inclinations

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