单向卸载条件下组合煤岩力学特性及声发射演化规律  

Mechanical properties and acoustic emission evolution of coal-rock combination under unidirectional unloading condition

作　　者：肖晓春[1,2] 刘海燕 丁鑫[1,2] 徐军 樊玉峰[1,2] XIAO Xiaochun;LIU Haiyan;DING Xin;XU Jun;FAN Yufeng(School of Mechanics and Engineering,Liaoning Technical University,Fuxin 123000,China;Liaoning Key Laboratory of Mining Environment and Disaster Mechanics,Liaoning Technical University,Fuxin 123000,China)

机构地区：[1]辽宁工程技术大学力学与工程学院,辽宁阜新123000 [2]辽宁工程技术大学辽宁省矿山环境与灾害力学重点实验室,辽宁阜新123000

出　　处：《煤炭科学技术》2023年第11期71-83,共13页Coal Science and Technology

基　　金：国家自然科学基金资助项目(51974186,52274203);辽宁工程技术大学创新团队联合资助项目(LNTU20TD-17)

摘　　要：针对深部巷道开挖卸荷扰动引起的冲击地压灾害问题,开展不同卸载条件下巷道围岩的变形破裂机理研究。以组合煤岩为研究对象,采用岩石力学真三轴试验机和声发射监测系统进行了恒轴压卸侧压的单向卸载试验,探究了卸载初始侧向应力及卸载速率影响下组合煤岩的力学特性,通过声发射信号特征反演了组合煤岩内部不同类型裂纹扩展规律,结合振铃计数特征参数量化了组合煤岩加卸载过程的损伤程序。结果表明:单向卸载条件下组合煤岩表现出明显的张剪复合破坏特征,煤体宏观上以剪切破坏为主,岩石以张拉破坏为主,卸载初始侧向应力的增加导致组合煤岩破坏程度加剧,卸载速率的提高促进了岩石试样应力卸载方向张拉裂纹的扩展;声发射参数RA–AF的变化准确描述了组合煤岩内部不同类型裂纹的占比,组合煤岩加卸载过程中大多以剪切裂纹的形式扩展,应力卸载阶段剪切裂纹的占比随卸载初始侧向应力的增加而降低,卸载速率的提高促进张拉裂纹占比的增加,剪切裂纹占比降低;通过研究声发射振铃计数标定的损伤发现卸载初始侧向应力和卸载速率是影响组合煤岩卸载阶段损伤发育程度的主要因素,卸载初始侧向应力超过20 MPa后其对组合煤岩卸载阶段的损伤基本不产生影响。研究成果可为深部巷道开挖冲击地压的发生机制与灾害防治提供参考。For the rock burst disaster problems caused by unloading disturbance of deep roadway excavation,the study on the deformation and fracture mechanism of roadway surrounding rock under different unloading conditions was carried out.Taking the coal-rock combination as the object of research,the true triaxial testing machine for rock mechanics and acoustic emission monitoring system was used to carry out the unidirectional unloading test of constant axial pressure and unloading lateral pressure,explore the mechanical properties of coal-rock combination under the influence of unloading initial confining pressure and unloading rate,invert the propagation laws of different types cracks in the coal-rock combination through the acoustic emission signal characteristics,and quantify the damage of coal-rock combination during loading and unloading with the ringing count.The results showed that coal-rock combination had obvious failure characteristics of tensile and shear composite under the condition of unidirectional unloading,macroscopically the coal was dominated by shear failure and the rock was dominated by tensile failure;the increase of the unloading initial confining pressure led to aggravating the failure of coal-rock combination,and the increase of unloading rate promoted the expansion of tensile cracks along the stress unloading direction of rock samples;the change of RA–AF of acoustic emission parameter accurately described the proportion of different types cracks in the coal-rock combination,coal-rock combination mostly expanded in the form of shear cracks during the loading and unloading process,the proportion of shear cracks decreased with the increase of the unloading initial lateral stress,and the increase of unloading rate promoted the increase of the proportion of tensile cracks in the stress unloading stage,the proportion of shear cracks decreased;it was found that unloading initial lateral stress and unloading rate were the main factors affecting the damage development of coal-rock combination in unload

关 键 词：应力路径 卸荷速率 组合煤岩 剪切裂纹占比 声发射演化规律 

分 类 号：TD315[矿业工程—矿井建设]