Multi-scale and multi-parameter testing and characterization of coal sandstone throughout loaded rupture
ZHANG Pingsong
LIU Chang
Abstract：Huainan mine has entered the critical period of Group A coal mining,with the in-crease of mining depth,the rock mechanics problems faced are more and more complex,coal sandstone as an important part of the quarry perimeter rock,the study of its mechanical prop-erties,geological and geophysical properties is crucial.From the perspectives of fine-scale ob-servation,specimens and actual measurements of rock layers,we obtain the fracture evolution characteristics,strain and electrode current response characteristics of coal sandstone,and comprehensively recognize the load-damaged fracture,parameter response characteristics and threshold values of coal sandstone.The results show that on the fine-scale,when the load rea-ches 70.2％σmax(maximum stress),the fine-scale parameters start to have a faster growth.On the specimen scale,for sandstone specimens with different water contents,the distributed fiber-optic strain values at the time of rupture were 613 × 10-6,787 × 10-6,933 × 10-6,and 1 522×10-6,respectively.The strength of sandstone specimens was reduced by the action of fissure water,and there was a quadratic relationship between the water content and the growth rate of the strain;the overall trend of the electrode currents experienced four stages of stable,slowly rising,slightly The overall trend of the electrode current went through four stages,such as smooth,slow rise,slight decline and sudden drop,and the values of the time ratio of rupture current(t1/t2)of sandstone specimens with different water contents were 95.4％,85.7％,73.2％and 60.5％in that order.As for the actual measurement of the rock layer,the distributed fiber-optic strain and electrode current response characteristics of the sandstone lay-ers throughout the back-mining process were obtained and are consistent with the multi-param-eter response characteristics of the indoor tests.The test results can provide support for the in-depth study of the mechanical properties and geo-geophysical properties of Group A coal sand-stone,the mechanism of fissure generation,as well as on-site detection practice and disaster early warning.
Keywords：coal measure sandstonemulti-scale researchmulti-field and multi-parameterdistributed optical fiberparallel electrical method
Publication Date：2025-01-29
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：14( 172-185 )