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Structural Engineering and Mechanics Volume 80, Number 5, December10 2021 , pages 523-538 DOI: https://doi.org/10.12989/sem.2021.80.5.523 |
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DEM numerical study on mechanical behaviour of coal with different water distribution models |
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Lihai Tan, Xin Cai, Ting Ren, Xiaohan Yang and Yichao Rui
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| Abstract | ||
| The mechanical behaviour and stability of coal mining engineering underground is significantly affected by ground water. In this study, nuclear magnetic resonance imaging (NMRI) technique was employed to determine the water distribution characteristics in coal specimens during saturation process, based on which the functional rule for water distribution was proposed. Then, using discrete element method (DEM), an innovative numerical modelling method was developed to simulate water-weakening effect on coal behaviour considering moisture content and water distribution. Three water distribution numerical models, namely surface-wetting model, core-wetting model and uniform-wetting model, were established to explore the water distribution influences. The feasibility and validity of the surface-wetting model were further demonstrated by comparing the simulation results with laboratory results. The investigation reveals that coal mechanical properties are affected by both water saturation coefficient and water distribution condition. For all water distribution models, micro-cracks always initiate and nucleate in the water-rich area and thus lead to distinct macro fracture characteristics. With the increase of water saturation coefficient, the failure of coal tends to be less violent with less cracks and ejected fragments. In addition, the corewetting specimen is more sensitive to water than specimens with other water distribution models. | ||
| Key Words | ||
| coal mechanical behaviour; discrete element method; nuclear magnetic resonance imaging; waterweakening effect; water distribution model | ||
| Address | ||
| Lihai Tan: School of Resource Environment and Safety Engineering, University of South China, Hengyang, 412001, PR China; School of Civil, Mining and Environmental Engineering, University of Wollongong, NSW 2522, Australia Xin Cai: School of Resources and Safety Engineering, Central South University, Changsha 410083, PR China Ting Ren: School of Civil, Mining and Environmental Engineering, University of Wollongong, NSW 2522, Australia Xiaohan Yang: School of Civil, Mining and Environmental Engineering, University of Wollongong, NSW 2522, Australia Yichao Rui: School of Resources and Safety Engineering, Central South University, Changsha 410083, PR China | ||