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

作　　者：Quanle Zou Zihan Chen Jinfei Zhan Chunmei Chen Shikang Gao Fanjie Kong Xiaofeng Xia 

机构地区：[1]State Key Laboratory of Coal Mine Disaster Dynamics and Control,School of Resources and Safety Engineering,Chongqing University,Chongqing 400044,China [2]School of Mining,Guizhou University,Guiyang 550025,China

出　　处：《International Journal of Mining Science and Technology》2023年第12期1527-1540,共14页矿业科学技术学报（英文版）

基　　金：This work was financially supported by the National Natural Science Foundation of China(No.52074041);the Chongqing Talent Program(No.cstc2022ycjh-bgzxm0077);the Postgraduate Research and Innovation Foundation of Chongqing,China(No.CYS23060).

摘　　要：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 fracture 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 proportion 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.

关 键 词：CT imaging Flow conductivity Three-dimensional reconstruction Proportion of fracture channels Cyclic loading and unloading 

分 类 号：TD82[矿业工程—煤矿开采]