Morphological evolution and flow conduction characteristics of fracture channels in fractured sandstone under cyclic loading and unloading

• Published in: International journal of mining science and technology Vol. 33; no. 12; pp. 1527 - 1540
• Main Authors: Zou, Quanle, Chen, Zihan, Zhan, Jinfei, Chen, Chunmei, Gao, Shikang, Kong, Fanjie, Xia, Xiaofeng
• Format: Journal Article
• Language: English
• Published: State Key Laboratory of Coal Mine Disaster Dynamics and Control,School of Resources and Safety Engineering,Chongqing University,Chongqing 400044,China%School of Mining,Guizhou University,Guiyang 550025,China 01.12.2023; Elsevier
• Subjects: CT imaging; Cyclic loading and unloading; Flow conductivity; Proportion of fracture channels; Three-dimensional reconstruction; CT imaging; Cyclic loading and unloading; Flow conductivity; Proportion of fracture channels; Three-dimensional reconstruction
• ISSN: 2095-2686
• DOI: 10.1016/j.ijmst.2023.11.003

In coal mining,rock strata are fractured under cyclic loading and unloading to form fracture channels.Fracture channels are the main flow narrows for gas.Therefore,expounding the flow conductivity of frac-ture channels in rocks on fluids is significant for gas flow in rock strata.In this regard,graded incremental cyclic loading and unloading experiments were conducted on sandstones with different initial stress levels.Then,the three-dimensional models for fracture channels in sandstones were established.Finally,the fracture channel percentages were used to reflect the flow conductivity of fracture channels.The study revealed how the particle size distribution of fractured sandstone affects the formation and expansion of fracture channels.It was found that a smaller proportion of large blocks and a higher pro-portion of small blocks after sandstone fails contribute more to the formation of fracture channels.The proportion of fracture channels in fractured rock can indicate the flow conductivity of those channels.When the proportion of fracture channels varies gently,fluids flow evenly through those channels.However,if the proportion of fracture channels varies significantly,it can greatly affect the flow rate of fluids.The research results contribute to revealing the morphological evolution and flow conductivity of fracture channels in sandstone and then provide a theoretical basis for clarifying the gas flow pattern in the rock strata of coal mines.