Characterization of strength and damage of hard rock pillars using a synthetic rock mass method

Zhang, Y.; Stead, Doug; Elmo, Davide

doi:10.1016/j.compgeo.2014.12.002

Cited by 28 publications

(7 citation statements)

References 36 publications

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“…Shkuratnik and Rudajev studied the characteristics of acoustic emission under uniaxial and triaxial compression [7][8][9]. Ma et al studied mechanical properties of coal and rock under uniaxial and triaxial compression [10][11][12]. Liang et al [13] carried out an experimental study of marble and red sandstone under uniaxial compression, and the relationship between AE parameters and loading rates was obtained.…”

Section: Introductionmentioning

confidence: 99%

Study of Acoustic Emission and Mechanical Characteristics of Coal Samples under Different Loading Rates

Gao

et al. 2015

Shock and Vibration

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To study the effect of loading rate on mechanical properties and acoustic emission characteristics of coal samples, collected from Sanjiaohe Colliery, the uniaxial compression tests are carried out under various levels of loading rates, including 0.001 mm/s, 0.002 mm/s, and 0.005 mm/s, respectively, using AE-win E1.86 acoustic emission instrument and RMT-150C rock mechanics test system. The results indicate that the loading rate has a strong impact on peak stress and peak strain of coal samples, but the effect of loading rate on elasticity modulus of coal samples is relatively small. When the loading rate increases from 0.001 mm/s to 0.002 mm/s, the peak stress increases from 22.67 MPa to 24.99 MPa, the incremental percentage is 10.23%, and under the same condition the peak strain increases from 0.006191 to 0.007411 and the incremental percentage is 19.71%. Similarly, when the loading rate increases from 0.002 mm/s to 0.005 mm/s, the peak stress increases from 24.99 MPa to 28.01 MPa, the incremental percentage is 12.08%, the peak strain increases from 0.007411 to 0.008203, and the incremental percentage is 10.69%. The relationship between acoustic emission and loading rate presents a positive correlation, and the negative correlation relation has been determined between acoustic emission cumulative counts and loading rate during the rupture process of coal samples.

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Section: Introductionmentioning

confidence: 99%

Study of Acoustic Emission and Mechanical Characteristics of Coal Samples under Different Loading Rates

Gao

et al. 2015

Shock and Vibration

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“…The loading scheme is another important factor when simulating static pillar behaviour using SRM. A pillar model can be loaded at a constant strain rate, or it can be loaded using an efficient and more accurate internal‐strain loading method . For the constant strain loading, the particles may not have enough time to relocate during the compression process, resulting in a higher peak strength and a more ductile post‐peak response.…”

Section: The Synthetic Rock Mass Methodsmentioning

confidence: 99%

“…This is largely attributed to its ability of explicitly simulating rock crack propagation . Recently, a Synthetic Rock Mass (SRM) method is developed to quantify mechanical properties of jointed rock mass . The SRM is an integrated model incorporating a discrete fracture network (DFN) within a Particle Flow Code 3D (PFC3D) particle assembly.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of confinement effect on jointed rock pillars using a Synthetic Rock Mass approach

Zhang

Zhao

2016

Num Anal Meth Geomechanics

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Confinement effect on jointed rock pillars is numerically characterised in this research using a Synthetic Rock Mass (SRM) approach. The SRM is an integrated model incorporating a discrete fracture network within a Particle Flow Code 3D particle assembly. In this paper, the confinement effect on a 3D jointed pillar SRM model is investigated in a series of simulations, including biaxial compression tests and true and conventional triaxial compression tests. The numerical results suggest that the applied confining stresses generally result in higher pillar strengths and ductile post-peak responses. More brittle post-peak behaviour is simulated in the biaxial and true triaxial tests when the pillar is confined by a high stress in one lateral direction and by a zero/low stress in the other lateral direction. This phenomenon is attributed to significant lateral pillar dilation in the less confined direction. Detailed pillar failure modes are monitored in the uniaxial and triaxial tests. Axial splitting fractures and long shear zones cutting through the pillar are simulated when the pillar is able to dilate in the direction of least confinement. Localised shearing along joints and failed rock blocks is the dominant failure mode when the pillar dilation is resisted by the applied confining stresses. The pillar remains relatively intact with limited cracking in the pillar core in the highly confined triaxial tests.

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“…Preexisting weak planes also have a significant effect on pillar behavior and failure. Owing to the complexity of the pillar system, numerical simulations are commonly used to demonstrate the interaction between newly generated and preexisting fractures in pillars [4,[71][72][73]. However, it was difficult to obtain a general conclusion on how the preexisting joints affected the pillar behavior and failure mode.…”

Section: Fractures In the Chain Pillarmentioning

confidence: 99%

“…However, it was difficult to obtain a general conclusion on how the preexisting joints affected the pillar behavior and failure mode. This is because there are so many parameters that play a role in the system [4,[71][72][73][74][75][76], such as orientation and size of the joint sets, strength of the weak plane, distributions and density of the joints, failure mode of the inserted joints, confinement applied on the pillar, and pillar size.…”

Section: Fractures In the Chain Pillarmentioning

confidence: 99%

A General Review on Longwall Mining-Induced Fractures in Near-Face Regions

Bai

2019

Geofluids

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It is believed that underground longwall mining usually produces fractures in the surrounding rocks. On the one hand, mining-induced fractures not only degrade the strength of the rock mass but also serve as main channels for fluids (e.g., water and methane). Fractures facilitate the failure of the rock mass and fluid inrush into working spaces. Therefore, mining-induced fractures are significant for the safety evaluation of underground structures and finding feasible solutions. On the other hand, the fractures are also beneficial for methane collection and coal fragmentation, which are essential for the successful operation of longwall top coal caving mining. Therefore, determining the characteristics of induced fractures is significant for underground longwall mining. From a global perspective, longwall mining-induced fractures in the overburden have been well studied, which improves the understanding of the mining pressure and ground control. However, induced fractures near the longwall face, which have more significant effects on mining activities, have not been summarized. The goal of this review paper is to provide a general summary of the current achievements in characterizing mining-induced fractures in near-face regions. The characteristics of mining-induced fractures in the coal wall, chain pillar, immediate roofs and top coal, and floors are reviewed and summarized. Remarks are made on the current progress of, fundamental problems with, and developments in methodologies for characterizing mining-induced fractures using methods such as field observations, small-scale laboratory tests, physical modeling, and numerical modeling. Based on a comprehensive analysis, the advantages and disadvantages of each method are discussed, and the ideal conditions for applying each of these methods are also recommended.

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Characterization of strength and damage of hard rock pillars using a synthetic rock mass method

Cited by 28 publications

References 36 publications

Study of Acoustic Emission and Mechanical Characteristics of Coal Samples under Different Loading Rates

Study of Acoustic Emission and Mechanical Characteristics of Coal Samples under Different Loading Rates

Characterisation of confinement effect on jointed rock pillars using a Synthetic Rock Mass approach

A General Review on Longwall Mining-Induced Fractures in Near-Face Regions

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