工程科学与技术2024，Vol.56Issue(4)：173-181,9.DOI:10.15961/j.jsuese.202300145
顶板砂岩直接拉伸破坏声发射特征及损伤本构模型
Acoustic Emission Characteristics and Damage Constitutive Model of Roof Sandstone During Direct Tensile Failure
摘要
Abstract
Due to the complex environmental occurrences and resource exploitation in deep coal mines,the risk of disasters such as roof falls has sharply increased,with most being directly caused by roof tensile failure.Therefore,it is urgent to explore the mechanical characteristics and the laws governing the evolution of damage in roof rock under tensile failure.To study the mechanical properties and spatiotemporal evolution char-acteristics of acoustic emission(AE)in roof sandstone under direct tensile loading conditions,uniaxial direct tensile tests and synchronous AE tests were carried out.Simultaneously,the differential processes of direct tensile failure between roof sandstone and coal seams were studied,and a stress-strain damage constitutive model for coal and rock under tensile stress was developed and validated.The test results reveal that:1)The average direct tensile strength of the roof sandstone is 5.01 MPa,which is approximately 7.6 times greater than that of coal.The direct tensile mechanical parameters of the roof sandstone exhibit strong variability,indicating that sandstone is prone to damage localization,leading to roof tensile failure.2)The post-peak release rate of elastic energy from sandstone is significantly higher than that from coal,exhibiting brittle charac-teristics.3)The analysis of AE spatial localization evolution revealed the mechanism of microcrack propagation and agglomeration nucleation process in roof sandstone at different tensile loading stages.Before the peak stress,only a small number of randomly distributed microcracks were generated,mainly resulting in the elastic deformation of the rock matrix.When the stress decreased by 20％after the peak,microcracks became localized,and then macroscopic cracks appeared and rapidly expanded until failure.4)A constitutive model based on AE characteristic paramet-ers for rock tensile damage was constructed.This model was validated using direct tensile and AE test data from sandstone and coal,demonstrat-ing a good fit.The model effectively characterized the post-peak strain softening characteristics of rock under direct tensile action.These research findings hold considerable implications for optimizing tunnel support structure design and for preventing and controlling coal mine disasters.关键词
砂岩/煤/直接拉伸/声发射/损伤本构模型Key words
sandstone/coal/direct tensile/acoustic emission/damage constitutive model分类
矿山工程引用本文复制引用
孙紫琬,张泽天,张茹,任利,刘小玲,张安林,张朝鹏..顶板砂岩直接拉伸破坏声发射特征及损伤本构模型[J].工程科学与技术,2024,56(4):173-181,9.基金项目
国家自然科学基金项目(52174084 （）
51804204) （）
四川省自然科学基金项目(2022NSFSC0406) （2022NSFSC0406）
