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

Abstract

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.

Keywords

hollow-cylinder granite / fracture mechanism / hole size / compressed deformation / crack propagation

References

[1] Zhu Z-n, Tian H, Mei G, et al. Experimental investigation on mechanical behaviors of Nanan granite after thermal treatment under conventional triaxial compression [J]. Environmental Earth Sciences, 2021, 80(2): 46

[2] Zhang Y-f, Zhang F, Yang K, et al. Effects of real-time high temperature and loading rate on deformation and strength behavior of granite [J]. Geofluids, 2022, 2022(1): 9426378

[3] Miao S-t, Pan P-z, Zhao X-g, et al. Experimental study on damage and fracture characteristics of Beishan granite subjected to high-temperature treatment with DIC and AE techniques [J]. Rock Mechanics and Rock Engineering, 2021, 54(2): 721-743

[4] Huang D, Liu Y, Cen D-f, et al. Effect of confining pressure on deformation and strength of granite in confined direct tension tests [J]. Bulletin of Engineering Geology and the Environment, 2022, 81(3): 110

[5] Ma Z-y, Zuo J-p, Zhu F, et al. Nonorthogonal failure behavior of roadway surrounding rock subjected to deep complicated stress [J]. Rock Mechanics and Rock Engineering, 2023, 56(9): 6261-6283

[6] Chen S-w, Liang F, Zuo S-y, et al. Evolution of deformation property and strength component mobilization for thermally treated Beishan granite under compression [J]. Journal of Central South University, 2021, 28(1): 219-234

[7] Wang Y, Han J-q, Xia Y-j, et al. New insights into the fracture evolution and instability warning predication for fissure-contained hollow-cylinder granite with different hole diameter under multi-stage cyclic loads [J]. Theoretical and Applied Fracture Mechanics, 2022, 119: 103363

[8] Robertson E C. Experimental study of the strength of rocks [J]. Geological Society of America Bulletin, 1955, 66(10): 1275

[9] Alsayed M I. Utilising the Hoek triaxial cell for multiaxial testing of hollow rock cylinders [J]. International Journal of Rock Mechanics and Mining Sciences, 2002, 39(3): 355-366

[10] Wang S-m, Wang J-q, Xiong X-r, et al. Zonal disintegration phenomenon based on triaxial dynamic load test of hollow cylindrical sandstone specimens [J]. Journal of Central South University, 2023, 30(4): 1311-1324

[11] Wu Q-h, Weng L, Zhao Y-l, et al. Influence of infilling stiffness on mechanical and fracturing responses of hollow cylindrical sandstone under uniaxial compression tests [J]. Journal of Central South University, 2021, 28(8): 2485-2498

[12] PANG Dong-dong, FENG Fei-sheng, JIANG Guang-hui, et al. Experimental study on lateral permeability evolution of sandstone under seepage-damage coupling [J]. Advances in Civil Engineering, 2020: 8861969. DOI: https://doi.org/10.1155/2020/8861969.

[13] Wang S-f, Li X-b, Du K, et al. Experimental study of the triaxial strength properties of hollow cylindrical granite specimens under coupled external and internal confining stresses [J]. Rock Mechanics and Rock Engineering, 2018, 51(7): 2015-2031

[14] Wang S-f, Li X-b, Yao J-r, et al. Experimental investigation of rock breakage by a conical pick and its application to non-explosive mechanized mining in deep hard rock [J]. International Journal of Rock Mechanics and Mining Sciences, 2019, 122: 104063

[15] Akl S A Y, Whittle A J. Validation of soil models for wellbore stability in ductile formations using laboratory TWC tests [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2017, 143(2): 04016095

[16] Liu H, Zhang K, Liu T, et al. Experimental and numerical investigations on tensile mechanical properties and fracture mechanism of granite after cyclic thermal shock [J]. Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 2021, 8(1): 18

[17] Wang Y, Han J Q, Song Z Y, et al. Macro-meso failure behavior of pre-flawed hollow-cylinder granite under multilevel cyclic loads: Insights from acoustic emission and post-test CT scanning [J]. Engineering Fracture Mechanics, 2021, 258: 108074

[18] Yang S-qi. Fracturing mechanism of compressed hollow-cylinder sandstone evaluated by X-ray micro-CT scanning [J]. Rock Mechanics and Rock Engineering, 2018, 51(7): 2033-2053

[19] Marina S, Imo-Imo E K, Derek I, et al. Modelling of hydraulic fracturing process by coupled discrete element and fluid dynamic methods [J]. Environmental Earth Sciences, 2014, 72(9): 3383-3399

[20] Li W, Liu Y-m, Yao X, et al. Study on deformation and strength characteristics of hollow cylindrical rock under complex loading conditions [J]. Geotechnical and Geological Engineering, 2020, 38(4): 3623-3630

[21] ZHANG Zeng-wei, CHEN Fan, ZHANG Chao, et al. Numerical simulation of rock failure process with a 3D grain-based rock model [J]. Advances in Civil Engineering, 2020: 8810022. DOI: https://doi.org/10.1155/2020/8810022.

[22] Yang S-q, Yang Z, Jing H-w, et al. Fracture evolution mechanism of hollow sandstone under conventional triaxial compression by X-ray micro-CT observations and three-dimensional numerical simulations [J]. International Journal of Solids and Structures, 2020, 190: 156-180

[23] Tang C-man. Numerical simulation of progressive rock failure and associated seismicity [J]. International Journal of Rock Mechanics and Mining Sciences, 1997, 34(2): 249-261

[24] Wang S Y, Sloan S W, Tang C A. Three-dimensional numerical investigations of the failure mechanism of a rock disc with a central or eccentric hole [J]. Rock Mechanics and Rock Engineering, 2014, 47(6): 2117-2137

[25] Zhu W C, Tang C A. Micromechanical model for simulating the fracture process of rock [J]. Rock Mechanics and Rock Engineering, 2004, 37(1): 25-56

[26] Lin P, Wong R H C, Tang C A. Experimental study of coalescence mechanisms and failure under uniaxial compression of granite containing multiple holes [J]. International Journal of Rock Mechanics and Mining Sciences, 2015, 77: 313-327

[27] Yu M-hong. Twin shear stress yield criterion [J]. International Journal of Mechanical Sciences, 1983, 25(1): 71-74

[28] Gay N C. Fracture growth around openings in thick-walled cylinders of rock subjected to hydrostatic compression [J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1973, 10(3): 209-233