Numerical investigation of the scale effect and anisotropy in the strength and deformability of coal

Gao, Fuqiang; Stead, Doug; Kang, Huan

doi:10.1016/j.coal.2014.10.003

Cited by 71 publications

(15 citation statements)

References 36 publications

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“…However, due to the size limitation of the servo press machine in the simulation test, the crack propagation characterizations in the deformation and failure process of the surrounding rock in the similar simulation test are relatively difficult, and it lacks direct internal observation approach to obtain the obvious characteristics of crack development. Numerical simulation can make up for this deficiency; for example, Gao et al [30] and Zhang et al [31] used UDEC, ABAQUS, and other software to conduct indepth studies on deformation and failure of roadways and instability of surrounding rock under actual size conditions.…”

Section: Scale Effect Of the Physical Simulationmentioning

confidence: 99%

Physical Simulation and Monitoring the Deformation and Fracture of Roadway in Coal Mining

Liu

Yang

Ding

et al. 2018

Advances in Civil Engineering

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Aiming at the large deformation and the dynamic fracture of roadway during the underground excavation or mining, a physical simulation and strain testing system was established, and the deformation process of surrounding body and its inner strain characteristics of the simulated roadway under loading was carried out. Results showed that the inner strain change of the measurement points can be divided into three types: the strain firstly increases and then decreases, the strain slowly increases and then increases sharply, and strain firstly reduces and then increases. The strain starting time is closely related to the failure path and boundary of tested samples. This paper suggested two criteria for determining the instability of roadways, which are a huge and faster increase of strain at the location of the roof and floor with high absolute value, or a small increase with a peak value or irregular fluctuation. This paper provides a new idea for the simulation of roadway instability and is significant in deeper understanding the deformation and destabilization of underground roadway.

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Section: Scale Effect Of the Physical Simulationmentioning

confidence: 99%

Physical Simulation and Monitoring the Deformation and Fracture of Roadway in Coal Mining

Liu

Yang

Ding

et al. 2018

Advances in Civil Engineering

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“… Rank or thermal maturity, grade or distribution and occurrence of mineral inclusions (Zhao et al, 2014a(Zhao et al, , 2014bGao et al, 2014);…”

Section: Introductionmentioning

confidence: 99%

Alternative methods for geomechanical characterisation of sub-bituminous coal, Surat Basin, Australia

Barbosa¹

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“…Instead, the coal media possesses properties of high heterogeneity and viscoelasticity (Gao et al, 2014), which could strongly attenuate the acoustic wave. The heterogeneity could be better approached through the model-building process.…”

Section: Viscoelastic Modelmentioning

confidence: 99%

“…Based on Darcy's law (Gao et al, 2014) So, the new fluid formula in a dynamic fracture can be written in equation (3.9). And with this equation, the new permeability formula under the wave dynamic can be written in…”

Section: Variable Width Of Cleatsmentioning

confidence: 99%

Numerical simulation of acoustic stimulation for enhancing coal seam gas reservoir permeability

Jiang¹

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Acoustic stimulation method has been recognized as one of the most effective methods for enhancing coal permeability and improving the production amount of gas. Laboratory data has proved that the geometrical parameters (width and length) of coal cleats, which are the crucial pathway for gas migration, could be highly increased by acoustic field stimulation. The main reason for this positive effect is that acoustic energy could induce the mechanical vibration effect around coal cleats. However, the basic mechanism of this effect is still poorly understood due to the limitation of experimental facilities; the progress and details about this effect cannot be directly observed. It is imperative to conduct proper numerical simulation for the technology to improve the understanding of mechanical vibration. And only based on the conclusion of simulation results, the engineering parameters for optimal stimulation effect could be found. This thesis addresses this key issue and demonstrates how exactly the mechanical vibration is induced and affect the original coal cleat system. This thesis focuses on conducting numerical simulation for acoustic wave induced mechanical vibration around the coal cleats. The primary contributions are summarized as follows:(1) The numerical simulation based on the staggered-grid finite differential method (FDM) is applied to simulate 3D wave propagation in a single coal cleat model. Two parameters, shear wave energy (SE) and variable width of cleat (DW), are introduced and implemented in the numerical model to explicitly evaluate the acoustic stimulation effects. The results indicate that these parameters could accurately represent the variations of acoustic energy and geometrical parameters of the coal cleat model.(2) The polarized wave induced wave dynamics in a coal sample with a single cleat model is numerically simulated and analyzed; the energy trapping and dynamic variation of fracture width in coal for the cleat model with three different filled media (i.e. air, water and weak mineral) are numerically analyzed and compared with each other subjected to different incident wave angles, and the optimal stimulation parameters are obtained through such sensitivity analysis. Simulation results show that the mechanical vibration is induced by the energy trapping effect; coal property (i.e. cleat and its filled media) and incident wave angles are crucial for acoustic stimulation to produce physical damages around coal cleats and enhance the permeability of fractured coal samples. II (3)The numerical simulation is further applied to simulate the viscoelastic wave propagation in 3D coal sample with a coal cleat system. Two kinds of coal cleat system model, orthogonal cleat sets (OCS) and T-junction cleat sets (TCS), are adopted to investigate the influence of coal cleats special structure for mechanical vibration. A stochastic model building process, which includes Monte Carlo method and von-Ká rmá n function, is proposed to better represent the structure of coal cleat system and hete...

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Numerical investigation of the scale effect and anisotropy in the strength and deformability of coal

Cited by 71 publications

References 36 publications

Physical Simulation and Monitoring the Deformation and Fracture of Roadway in Coal Mining

Physical Simulation and Monitoring the Deformation and Fracture of Roadway in Coal Mining

Alternative methods for geomechanical characterisation of sub-bituminous coal, Surat Basin, Australia

Numerical simulation of acoustic stimulation for enhancing coal seam gas reservoir permeability

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