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

作　　者：孙紫琬 张泽天[1,2,3] 张茹 任利[1,3] 刘小玲 张安林[1,2] 张朝鹏 SUN Ziwan;ZHANG Zetian;ZHANG Ru;REN Li;LIU Xiaoling;ZHANG Anlin;ZHANG Zhaopeng(State Key Lab.of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Eng.,Sichuan Univ.,Chengdu 610065,China;College of Water Resource&Hydropower,Sichuan Univ.,Chengdu 610065,China;Key Lab.of Deep Underground Sci.and Eng.for Ministry of Education,Sichuan Univ.,Chengdu 610065,China)

机构地区：[1]四川大学深地工程智能建造与健康运维全国重点实验室,四川成都610065 [2]四川大学水利水电学院,四川成都610065 [3]四川大学深地科学与工程教育部重点实验室,四川成都610065

出　　处：《工程科学与技术》2024年第4期173-181,共9页Advanced Engineering Sciences

基　　金：国家自然科学基金项目(52174084,51804204);四川省自然科学基金项目(2022NSFSC0406)。

摘　　要：深部煤炭资源开采常面临复杂的赋存及采动力学环境,冒顶等灾害事故风险激增。顶板拉破坏是其中一个重要诱因,故亟需深入探究顶板岩石拉伸破坏力学特性及损伤演化规律。通过开展顶板砂岩单轴直接拉伸试验和全过程同步声发射测试,探究了砂岩的直接拉伸力学特性和声发射时空演化特征,对比分析了顶板砂岩与煤的直接拉伸破坏差异性过程规律,同时发展并对比验证了煤岩拉伸全应力应变损伤本构模型。结果表明:1)顶板砂岩平均直接抗拉强度为5.01MPa,约为煤体直接抗拉强度的7.6倍;顶板砂岩直接拉伸力学参数变异性强,反映出砂岩易产生破坏局部化而导致顶板拉破坏。2)砂岩在直接拉伸峰后的弹性能释放速率显著高于煤体,表现出明显的脆性特征。3)声发射空间定位演化分析揭示了顶板砂岩不同拉伸加载阶段的微裂纹扩展与空间集聚成核过程机制,同时发现峰值应力前仅有少量随机分布的微裂纹产生,主要发生基质的弹性变形;峰值后应力下降20%时,微裂纹局部化,此后宏观裂纹出现并快速扩展,直至破坏。4)构建了基于声发射特征参数的煤岩拉伸损伤本构模型,砂岩和煤的直接拉伸和声发射试验数据的验证显示其具有良好的拟合效果,可较好地表征岩石在直接拉伸作用下的峰后应变软化特征。研究成果对巷道支护结构设计优化,以及煤矿灾害防治具有重要指导意义。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 characteristics 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 characteristics.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 parameters for rock tensile damage was constructed.This model was validated using direct tensile and AE test data from sandstone and coal,demonstrating a good fit.The model effectively characterize

关 键 词：砂岩 煤 直接拉伸 声发射 损伤本构模型 

分 类 号：TD315[矿业工程—矿井建设]