Macro-meso fracture evolution mechanism of hollow cylindrical granite with different hole diameters under conventional triaxial compression  

常规三轴压缩下不同孔径空心圆柱花岗岩宏细观破裂演化机制

作　　者：ZENG Lin-hai ZHANG Dao-bing ZHANG Jia-hua ZHANG Biao YIN Hua-dong 曾林海;张道兵;张佳华;张标;尹华东(School of Resource Environment and Safety Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines,Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines,Hunan University of Science and Technology,Xiangtan 411201,China;School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)

机构地区：[1]School of Resource Environment and Safety Engineering,Hunan University of Science and Technology,Xiangtan 411201,China [2]Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines,Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines,Hunan University of Science and Technology,Xiangtan 411201,China [3]School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,China

出　　处：《Journal of Central South University》2024年第9期3281-3294,共14页中南大学学报（英文版）

基　　金：Projects(52074116,51804113)supported by the National Natural Science Foundation of China。

摘　　要：In order to study and analyze the stability of engineering rock mass under non-uniform triaxial stress and obtain the evolution mechanism of the whole process of fracture,a series of conventional triaxial compression tests and three-dimensional numerical simulation tests were carried out on hollow granite specimens with different diameters.The bearing capacity of hollow cylindrical specimen is analyzed based on elasticity.The results show that:1)Under low confining pressure,the tensile strain near the hole of the hollow cylindrical specimen is obvious,and the specimen deformation near the hole is significant.At the initial stage of loading,the compressive stress and compressive strain of the specimen are widely distributed.With the progress of loading,the number of microelements subjected to tensile strain gradually increases,and even spreads throughout the specimen;2)Under conventional triaxial compression,the cracking position of hollow cylinder specimens is concentrated in the upper and lower parts,and the final fracture mode is generally compressive shear failure.The final fracture mode of complete specimen is generally tensile fracture.Under high confining pressure,the tensile cracks of the sample are concentrated in the upper and lower parts and are not connected,while the cracks of the upper and lower parts of the intact sample will expand and connect to form a fracture surface;3)In addition,the tensile crack widths of intact and hollow cylindrical specimens under low confining pressure are larger than those under high confining pressure.为了研究和分析工程岩体在非均匀三轴应力作用下的稳定性,获得断裂全过程的演化机制,对不同直径(孔径d=0、10、15和20 mm)的空心花岗岩试件进行了一系列常规三轴压缩试验(围压σ3为0、10、20和30 MPa)和三维数值模拟试验。探讨了围压作用下不同孔尺寸的空心花岗岩宏观细观破裂演化机制。并从弹性力学的角度分析了空心圆柱试件的承载力。结果表明:1)低围压下,空心柱状试件孔附近拉伸应变明显,孔附近试件变形显著;加载初期,试件的压应力和压应变分布较广。随着加载的进行,受拉伸应变影响的微量元素数量逐渐增加,甚至遍布整个试样。2)在常规三轴压缩下,空心圆柱体试件的开裂位置集中在上部和下部,最终断裂方式一般为压剪破坏。完整试样的最终断裂方式一般为拉伸断裂。在高围压(σ3=30 MPa)下,试样的拉伸裂纹集中在上、下两部分,不连通,而完好试样的上、下两部分的裂纹会扩展并连通,形成断裂面。3)此外,低围压下的完整柱状试件和空心柱状试件的拉伸裂缝宽度大于高围压下的试件。

关 键 词：hollow-cylinder granite fracture mechanism hole size compressed deformation crack propagation 

分 类 号：TD313[矿业工程—矿井建设]