Energy evolution and water immersion-induced weakening in sandstone roof of coal mines
Wenjie Liu1
Ke Yang2
Shuai Zhang3
Zhainan Zhang1
Rijie Xu1
1.State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,Anhui University of Science and Technology,Huainan 232001,China;National and Local Joint Engineering Research Center of Precision Coal Mining,Anhui University of Science and Technology,Huainan 232001,Anhui,China;Key Laboratory of Mining Coal Safety and Efficiently Constructed By Anhui Province and Ministry of Education,Anhui University of Science and Technology,Huainan 232001,China2.State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,Anhui University of Science and Technology,Huainan 232001,China;Hefei Comprehensive National Science Center,Institute of Energy,Hefei 230031,Anhui,China;National and Local Joint Engineering Research Center of Precision Coal Mining,Anhui University of Science and Technology,Huainan 232001,Anhui,China;Key Laboratory of Mining Coal Safety and Efficiently Constructed By Anhui Province and Ministry of Education,Anhui University of Science and Technology,Huainan 232001,China3.State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology,Xuzhou 221116,Jiangsu,China
摘要：The instability of underground spaces in abandoned coal mines with water-immersed rocks is one of the main hazards hindering the geothermal energy use and ecological restoration of post-mining areas.This study conducted graded cyclic loading-unloading tests of five groups of sandstone samples with different water contents.The evolution of input,elastic,dissipated,damping,and plastic energies were explored,considering the damping effect.The normalized plastic energy serves to characterize the damage evolution of sandstone samples,whose failure characteristics were analyzed from both the macroscopic and microscopic perspectives.X-ray diffraction technique and scanning electron microscopy were used to reveal the softening mechanism of sandstone.The results show that under graded cyclic loading,input energy,elastic energy,and dissipated energy all increase gradually,and the fraction of elastic energy increases gradually at first and then tends to stabilize.The variation in the fraction of dissipated energy is opposite to that of elastic energy.In each cycle,the input energy is stored primarily in the form of elastic energy,whereas the dissipated energy is used primarily to overcome the damping of sandstone.When the normalized number of cycles approached unity,the plastic energy fraction sharply increases,while that of the dampening energy drops abruptly.With increasing water content,the effect of pore water on the lubrication,the water wedge,and dissolution of mineral particles becomes more obvious,reducing the elastic-storage limit of sandstone,meanwhile the sandstone damage factor increases significantly under the same cycle and the failure mode changes from brittle to ductile.
机标关键词：evolutionminesenergywaterroofcoalimmersioninduced
论文发表日期：2022-08-28
在线出版日期：2025-08-15（本平台首次上网日期，不代表文献的发表时间）
页数：14( 93-106 )
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