Spatio-temporal evolution of pore and fracture structures in coal induced by initial damage and creep behavior:A real-time NMR-based approach

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外文摘要：Understanding the impact of mining disturbances and creep deformation on the macroscopic deforma-tion and the microscopic pore and fracture structures(MPFS)of coal is paramount for ensuring the secure extraction of coal resources.This study conducts cyclic loading-unloading and creep experiments on coal using a low-field nuclear magnetic resonance(NMR)experimental apparatus which is equipped with mechanical loading units,enabling real-time monitoring the T2 spectrum.The experiments indicated that cyclic loading-unloading stress paths initiate internal damage within coal samples.Under identical creep stress conditions,coal samples with more initial damages had more substantial instantaneous deforma-tion and creep deformation during the creep process.After undergoing nearly 35 h of staged creep,the total strains for coal samples CC01,CC02,and CC03 reach 2.160％,2.261％,and 2.282％,respectively.In the creep stage,the peak area ratio of seepage pores and microfractures(SPM)gradually diminishes.A higher degree of initial damage leads to a more pronounced compaction trend in the SPM of coal samples.Considering the porosity evolution of SPM during the creep process,this study proposes a novel fractional derivative model for the porosity evolution of SPM.The efficacy of the proposed model in predicting porosity evolution of SPM is substantiated through experimental validation.Furthermore,an analysis of the impact mechanisms on key parameters in the model was carried out.

外文关键词：

CoalMicroscopic pore and fracture structuresInitial damageCreep behaviorFractional porosity model of seepage pores and microfracturesNuclear magnetic resonance

作者：

Lei Zhang、Yimeng Wang、Mingzhong Gao、Wenhao Jia、Senlin Xie、Wei Hou、Xiangyu Wang、Hao Zhang

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作者单位：

College of Safety & Emergency Management Engineering,Taiyuan University of Technology,Taiyuan 030024,China

School of Energy and Mining Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China

State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering,Shenzhen University,Shenzhen 518060,China

School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China

School of Applied Science,Taiyuan University of Science and Technology,Taiyuan 030024,China

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出版年：

2024

DOI：

10.1016/j.ijmst.2024.09.003

矿业科学技术学报(英文版)

中国矿业大学

矿业科学技术学报(英文版)

CSTPCDEI

影响因子：1.222

ISSN：2095-2686

年,卷(期)：2024.34(10)