煤岩强度及变形特征的微细观损伤机理

Micro and meso-damage mechanism of coal's strength and deformation characteristics

利用MTS815.03电液伺服岩石力学试验系统和S250Mk3扫描电镜对三种煤岩性能及形貌进行分析观察,采用损伤力学分析方法对煤岩强度和变形特征的微细观机理进行了研究.结果表明,煤岩微细观损伤变量对其宏观力学参数影响很大,同为石炭二叠系兖州煤田的鲍店矿3煤和许厂矿3煤的原生损伤变量分别比新河矿3煤减少68·5%和50·6%,其单轴抗压强度分别增加224·8%和109·9%,弹性模量分别增加147·3%和66·9%.同时,随损伤变量减小,煤的单轴压缩破坏逐渐由塑性向脆性转变.煤岩宏观力学性质与其微细观损伤密切相关.

The properties and morphological structures of three types of coal rocks were experimentally analyzed with MTS815.03 servo-control rock mechanical test system and S250Mk3 scanning electronic microscope.The micro and meso-damage mechanisms of the coal＇s strength and deformation characteristics were studied with using the theory of damage mechanics.It is shown that the micro and meso-damage variable has great influence on the coal＇s macroscopic mechanical parameters.The original damage variables of No.3 coal seam in Baodian Colliery and No.3 coal seam in Xuchang Colliery,which both belong to carboniferous-permian Yanzhou Coalfield,decrease by 68.5% and 50.6% compared with No.3 coal seam in Xinhe Colliery,the uniaxial compressive strengths increase by 224.8% and 109.9%,and the elastic moduli increase by 147.3% and 66.9%,respectively.With decreasing damage variable,the uniaxial compression failure gradually changes from plastic to brittle.Macroscopic mechanical properties of the coal rocks are closely related to micro and meso-damage.