Effects of confining pressure on deformation failure behavior of jointed rock

Abstract

for a deeper understanding of the deformation failure behavior of jointed rock, numerical compression simulations are carried out on a rock specimen containing non-persistent joints under confining pressure with the bonded-particle model. The microscopic parameters which can reflect the macroscopic mechanical properties and failure behavior of artificial jointed specimens are firstly calibrated. Then, the influence of joint inclination and confining pressure on stress — strain curves, crack patterns, and contact force distributions of jointed rock are investigated. The simulation results show that both the compressive strength and elastic modulus of the specimens increase with increasing confining pressure, and these two mechanical parameters decrease first and then increase with the increase of joints inclination. The sensitivity of strength and elastic modulus to confining pressure is not the same in different joints inclinations, which has the least impact on specimens with α =90°. Under low confining pressure, the failure modes are controlled by the joint inclination. As the confining pressure increased, the initiation and propagation of tensile crack are gradually inhibited, and the failure mode is transferred from tensile failure to shear-compression failure. Finally, the reinforcement effect of prestressed bolt support on engineering fractured rock mass is discussed.

Keywords

stability of surrounding rock / non-persistent joints / confining pressure / cracking process / discrete element method (DEM)

References

[1] BobetA. The initiation of secondary cracks in compression [J]. Engineering Fracture Mechanics, 2000, 66(2): 187-219

[2] HuangR Q, HuangD. Evolution of rock cracks under unloading condition [J]. Rock Mechanics and Rock Engineering, 2014, 47(2): 453-466

[3] ZhongZ, DaH, ZhangY-F, et al.. Experimental study on the effects of unloading normal stress on shear mechanical behaviour of sandstone containing a parallel fissure pair [J]. Rock Mechanics and Rock Engineering, 2020, 53(4): 1647-1663

[4] LajtaiE Z, CarterB J, DuncanE J S. En echelon crack-arrays in potash salt rock [J]. Rock Mechanics and Rock Engineering, 1994, 27(2): 89-111

[5] DaH, CenD-F, MaG-W, et al.. Step-path failure of rock slopes with intermittent joints [J]. Landslides, 2015, 12(5): 911-926

[6] ParkC H, BobetA. Crack initiation, propagation and coalescence from frictional flaws in uniaxial compression [J]. Engineering Fracture Mechanics, 2010, 77(14): 2727-2748

[7] BobetA, EinsteinH H. Fracture coalescence in rocktype materials under uniaxial and biaxial compression [J]. International Journal of Rock Mechanics and Mining Sciences, 1998, 35(7): 863-888

[8] LajtaiE Z. Brittle fracture in compression [J]. International Journal of Fracture, 1974, 10(4): 525-536

[9] YangS-Q, JingH-W. Strength failure and crack coalescence behavior of brittle sandstone samples containing a single fissure under uniaxial compression [J]. International Journal of Fracture, 2011, 168(2): 227-250

[10] WongL N Y, EinsteinH H. Crack coalescence in molded gypsum and carrara marble: Part 1. macroscopic observations and interpretation [J]. Rock Mechanics and Rock Engineering, 2009, 42(3): 475-511

[11] ChenM, YangS-Q, PathegamaG R, et al.. Fracture processes of rock-like specimens containing nonpersistent fissures under uniaxial compression [J]. Energies, 2018, 12(1): 79

[12] ZhouX-P, ZhangJ-Z, WongL N Y. Experimental study on the growth, coalescence and wrapping behaviors of 3D cross-embedded flaws under uniaxial compression [J]. Rock Mechanics and Rock Engineering, 2018, 5151379-1400

[13] ZhouX-P, ZhangJ-Z, QianQ-H, et al.. Experimental investigation of progressive cracking processes in granite under uniaxial loading using digital imaging and AE techniques [J]. Journal of Structural Geology, 2019, 126: 129-145

[14] ZhouX-P, WangY-T, ZhangJ-Z, et al.. Fracturing behavior study of three-flawed specimens by uniaxial compression and 3D digital image correlation: Sensitivity to brittleness [J]. Rock Mechanics and Rock Engineering, 2019, 52(3): 691-718

[15] WongL N Y, EinsteinH H. Crack coalescence in molded gypsum and Carrara marble: Part 2—Microscopic observations and interpretation [J]. Rock Mechanics and Rock Engineering, 2009, 42(3): 513-545

[16] LeeH, JeonS. An experimental and numerical study of fracture coalescence in pre-cracked specimens under uniaxial compression [J]. International Journal of Solids and Structures, 2011, 48(6): 979-999

[17] ZhangJ-Z, ZhouX-P. AE event rate characteristics of flawed granite: From damage stress to ultimate failure [J]. Geophysical Journal International, 2020, 222(2): 795-814

[18] ChenX, LiaoZ-H, PengX. Deformability characteristics of jointed rock masses under uniaxial compression [J]. International Journal of Mining Science and Technology, 2012, 22(2): 213-221

[19] LinQ-B, CaoP, MengJ-J, et al.. Strength and failure characteristics of jointed rock mass with double circular holes under uniaxial compression: Insights from discrete element method modelling [J]. Theoretical and Applied Fracture Mechanics, 2020, 109: 102692

[20] LinQ-B, CaoP, LiuY-Z, et al.. Mechanical behaviour of a jointed rock mass with a circular hole under compression-shear loading: Experimental and numerical studies [J]. Theoretical and Applied Fracture Mechanics, 2021, 114102998

[21] ZhouX P, YangH Q. Multiscale numerical modeling of propagation and coalescence of multiple cracks in rock masses [J]. International Journal of Rock Mechanics and Mining Sciences, 2012, 5515-27

[22] BiJ, ZhouX P, QianQ H. The 3D numerical simulation for the propagation process of multiple pre-existing flaws in rock-like materials subjected to biaxial compressive loads [J]. Rock Mechanics and Rock Engineering, 2016, 49(5): 1611-1627

[23] WangY-T, ZhouX-P, ShouY-D. The modeling of crack propagation and coalescence in rocks under uniaxial compression using the novel conjugated bond-based peridynamics [J]. International Journal of Mechanical Sciences, 2017, 128–129: 614-643

[24] CamonesL A M, VargasE D A, De FigueiredoR P, et al.. Application of the discrete element method for modeling of rock crack propagation and coalescence in the step-path failure mechanism [J]. Engineering Geology, 2013, 153: 80-94

[25] HuangY-H, YangS-Q, RanjithP G, et al.. Strength failure behavior and crack evolution mechanism of granite containing pre-existing non-coplanar holes: Experimental study and particle flow modeling [J]. Computers and Geotechnics, 2017, 88: 182-198

[26] BahaaddiniM, SharrockG, HebblewhiteB K. Numerical investigation of the effect of joint geometrical parameters on the mechanical properties of a non-persistent jointed rock mass under uniaxial compression [J]. Computers and Geotechnics, 2013, 49: 206-225

[27] ChenM, YangS-Q, RanjithP G, et al.. Cracking behavior of rock containing non-persistent joints with various joints inclinations [J]. Theoretical and Applied Fracture Mechanics, 2020, 109: 102701

[28] CaoR-H, CaoP, LinH, et al.. Mechanical behavior of brittle rock-like specimens with pre-existing fissures under uniaxial loading: Experimental studies and particle mechanics approach [J]. Rock Mechanics and Rock Engineering, 2016, 49(3): 763-783

[29] FanX, KulatilakeP H S W, ChenX. Mechanical behavior of rock-like jointed blocks with multi-non-persistent joints under uniaxial loading: A particle mechanics approach [J]. Engineering Geology, 2015, 19017-32

[30] SagongM, BobetA. Coalescence of multiple flaws in a rock-model material in uniaxial compression [J]. International Journal of Rock Mechanics and Mining Sciences, 2002, 39(2): 229-241

[31] ZhouX P, ChengH, FengY F. An experimental study of crack coalescence behaviour in rock-like materials containing multiple flaws under uniaxial compression [J]. Rock Mechanics and Rock Engineering, 2014, 47(6): 1961-1986

[32] LiuJ-F, YangH-Q, XiaoY, et al.. Macro-mesoscopic fracture and strength character of pre-cracked granite under stress relaxation condition [J]. Rock Mechanics and Rock Engineering, 2018, 51(5): 1401-1412

[33] YangS Q, JiangY Z, XuW Y, et al.. Experimental investigation on strength and failure behavior of pre-cracked marble under conventional triaxial compression [J]. International Journal of Solids and Structures, 2008, 45(17): 4796-4819

[34] DaH, GuD-M, YangC, et al.. Investigation on mechanical behaviors of sandstone with two preexisting flaws under triaxial compression [J]. Rock Mechanics and Rock Engineering, 2016, 49(2): 375-399

[35] YangX-X, KulatilakeP H S W, JingH-W, et al.. Numerical simulation of a jointed rock block mechanical behavior adjacent to an underground excavation and comparison with physical model test results [J]. Tunnelling and Underground Space Technology, 2015, 50: 129-142

[36] ZhouX-P, PengS-L, ZhangJ-Z, et al.. Failure characteristics of coarse and fine sandstone containing two parallel fissures subjected to true triaxial stresses [J]. Theoretical and Applied Fracture Mechanics, 2021, 112: 102932

[37] YangS-Q, ChenM, JingH-W, et al.. A case study on large deformation failure mechanism of deep soft rock roadway in Xin’An coal mine, China [J]. Engineering Geology, 2017, 21789-101

[38] ZANG Chuan-wei, CHEN Yang, CHEN Miao, et al. Research on deformation characteristics and control technology of soft rock roadway under dynamic disturbance [J]. Shock and Vibration, 2021: 6625233. DOI: https://doi.org/10.1155/2021/6625233.

[39] WuK, ShaoZ-S, QinS. An analytical design method for ductile support structures in squeezing tunnels [J]. Archives of Civil and Mechanical Engineering, 2020, 20(3): 1-13

[40] QinS, WuK, ShaoZ-S. Analytical assessment of coupled influences of surrounding rock reinforcement and deformation release on tunnel response [J]. Geomechanics and Engineering, 2021, 26(6): 541-550

[41] ZhangG-C, ZangC-W, ChenM, et al.. Ground response of entries driven adjacent to a retreating longwall panel [J]. International Journal of Rock Mechanics and Mining Sciences, 2021, 138104630

[42] YangS-Q, ChenM, HuangY-H, et al.. An experimental study on fracture evolution mechanism of a non-persistent jointed rock mass with various anchorage effects by DSCM, AE and X-ray CT observations [J]. International Journal of Rock Mechanics and Mining Sciences, 2020, 134104469

[43] YangS-Q, ChenM, TaoY. Experimental study on anchorage mechanical behavior and surface cracking characteristics of a non-persistent jointed rock mass [J]. Rock Mechanics and Rock Engineering, 2021, 54(3): 1193-1221