三维尺度下岩桥倾角与矿物结构对煤体损伤破坏影响研究  

Study on the influences of rock bridge dip angle and mineral structure on coal damage and failure at three-dimensional scale

作　　者：王磊[1] 商瑞豪 朱传奇[1] 刘怀谦 袁秋鹏 李少波[1] 陈礼鹏 WANG Lei;SHANG Ruihao;ZHU Chuanqi;LIU Huaiqian;YUAN Qiupeng;LI Shaobo;CHEN Lipeng(State Key Laboratory of Mine Response and Disaster Prevention and Control in Deep Coal Mine,Anhui University of Science and Technology,Huainan,Anhui 232001,China)

机构地区：[1]安徽理工大学深部煤矿采动响应与灾害防控国家重点实验室,安徽淮南232001

出　　处：《岩石力学与工程学报》2024年第9期2108-2124,共17页Chinese Journal of Rock Mechanics and Engineering

基　　金：安徽省科技重大专项项目(202203a07020010);国家自然科学基金资助项目(52004007)。

摘　　要：为探究三维尺度下岩桥倾角与矿物结构对煤体损伤破坏的影响,以原煤预制不同岩桥倾角的双裂隙试样,开展单轴加载试验,借助CT扫描设备对试样压缩破坏过程进行阶段性扫描,采用阈值分割、三维重构等图像处理技术以及数字体积相关方法,分析受载煤样内部裂隙动态演化规律及变形损伤特性,并结合PFC3D模拟程序,探究试样加载全程不同阶段的内部应力分布特征。研究结果表明:随着岩桥倾角的增加,煤样宏观强度呈现出逐渐减小的趋势;受预制裂隙的影响,煤样X,Y,Z向位移场演化特征存在差异,X向位移场中的局部高位移区随着加载由岩桥区域向端部转移,Y向位移场加载全过程中局部高位移区始终徘徊在岩桥区域及预制裂隙周围,Z向位移场在各加载阶段均呈现出明显的分层现象,位移量小且均匀;不同岩桥倾角双裂隙煤样主要包括3种裂纹扩展类型及4种贯通模式,根据裂纹的扩展路径及破坏面上受力特征,得到0°和90°岩桥倾角煤样破坏模式为张拉破坏,30°和60°岩桥倾角煤样破坏模式为拉剪复合破坏;新生裂纹扩展与矿物赋存状态的关系主要包括包裹型扩展、绕砾型扩展以及穿砾型扩展3种形式,其中,穿砾型扩展出现次数最多,包裹型扩展最少;通过模拟试验可知,含双裂隙煤样各个方向的受力特征在峰值阶段存在差异,当切片位置由试样外部向试样内部延伸时,Y,Z向及总应力数值均呈现出逐渐增大的趋势,而X向应力数值则呈现出先减小后增加的现象。In order to explore the effects of rock bridge inclination angle and mineral structure on coal body damage and failure at a three-dimensional scale,uniaxial loading tests are carried out on double-crack samples prefabricated from raw coal with different rock bridge inclination angles,and phased scanning of the compression failure process is carried out with CT scanning equipment.Image processing techniques such as threshold segmentation,3D reconstruction and digital volume correlation methods were used to analyze the dynamic evolution of internal cracks and deformation and damage characteristics of coal samples,and the PFC3D simulation program was used to explore the internal stress distribution characteristics at different stages of the loading process.The results show that the macro-strength of coal samples decreases gradually with the increase of rock bridge angle.The evolution characteristics of the displacement fields in X,Y and Z directions are different due to the influence of prefabricated fractures on coal samples.The local high displacement area in X direction shifts from the rock bridge area to the end with the loading,while the local high displacement area always drifts around the rock bridge area and the prefabricated fracture in the whole loading process of Y direction,and the Z direction displacement field presents obvious stratification at each loading stage.The displacement is small and uniform.According to the crack propagation path and the stress characteristics of the failure surface,the failure mode of coal samples with rock bridge angles of 0°and 90°is tensile failure,and the failure mode of coal samples with rock bridge angles of 30°and 60°is tensile shear compound failure.The relationship between the growth of new crack and the occurrence state of mineral mainly includes three types:encapsulation propagation,around gravel propagation and through gravel propagation.Among them,through gravel propagation is the most frequent and wrapped propagation is the least.The simulation results show

关 键 词：岩石力学 岩桥倾角 矿物结构 CT扫描 颗粒流模拟 损伤破坏 

分 类 号：TU45[建筑科学—岩土工程]