Crack propagation behavior in sandstone during unloading confining pressure under different seepage pressures

Abstract

The unloading confining pressure tests were conducted on sandstone under the seepage pressure to reveal the relationships between the deformation characteristics and permeability and the stress paths and seepage pressure of the rock. The weights of influences of the confining pressure and seepage pressure on the damage of sandstone are quantified by symbolic statistics. Experimental results show that with the increasing confining pressure, the characteristic stress increases, and the growth rates of crack strain corresponding to the damage stress as well as the peak stress both decrease. However, with the increase of the seepage pressure, the characteristic stress decreases, the initial crack volumetric strain corresponding to the initiation stress reduces, the crack-growth volumetric strain corresponding to the damage stress increases and the growth rates of crack strain corresponding to the damage stress as well as the peak stress all increase. The permeability decreases slowly at first and then increases dramatically in the process of unloading confining pressure. Under the same confining pressure, the brittleness index and crack strain growth rates are the highest in the unloading test with seepage pressure, while they are moderate in the conventional unloading test, and the lowest in the loading test. The confining pressure is extremely correlated with the peak strength, axial strain, circumferential strain, crack circumferential strain corresponding to the peak strength. The seepage pressure is extremely correlated with growth rates of both crack axial strain and crack circumferential strain.

Keywords

unloading confining pressure / coupled hydro-mechanical effect / characteristic stress / growth rate of crack strain

References

[1] XuP, ZhangL, ZhangJ, et al. . Progressive failure characteristics and failure symptoms of straight-walled arched sandstone tunnels [J]. Acadlore Transactions on Geosciences, 2023, 2(1): 46-57

[2] ZhangL, ZhangD, WangJ, et al. . A nonlinear creep model of rocks based on memory-dependent derivative [J]. Construction and Building Materials, 2023, 391: 131618

[3] AlkanH. Percolation model for dilatancy-induced permeability of the excavation damaged zone in rock salt [J]. International Journal of Rock Mechanics and Mining Sciences, 2009, 46(4): 716-724

[4] LiuH, WuP. Stability analysis of gentle dip thick ore body mining based on the integration of SURPAC-FLAC3D [J]. Acadlore Transactions on Geosciences, 2023, 2(2): 58-69

[5] ZhangL, ChaoW, LiuZ, et al. . Crack propagation characteristics during progressive failure of circular tunnels and the early warning thereof based on multi-sensor data fusion [J]. Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 2022, 8(5): 1

[6] XueY, GaoF, GaoY, et al. . Quantitative evaluation of stress-relief and permeability-increasing effects of overlying coal seams for coal mine methane drainage in Wulan coal mine [J]. Journal of Natural Gas Science and Engineering, 2016, 32122-137

[7] ZhangL, ZhangD, WangZ, et al. . Constructing a three-dimensional creep model for rocks and soils based on memory-dependent derivatives: A theoretical and experimental study [J]. Computers and Geotechnics, 2023, 159105366

[8] WangJ A, ParkH D. Fluid permeability of sedimentary rocks in a complete stress-strain process [J]. Engineering Geology, 2002, 63(3–4): 291-300

[9] XuP, YangS. Permeability evolution of sandstone under short-term and long-term triaxial compression [J]. International Journal of Rock Mechanics and Mining Sciences, 2016, 85152-164

[10] LiS, WuD, XieW, et al. . Effect of confining presure, pore pressure and specimen dimension on permeability of Yinzhuang Sandstone [J]. International Journal of Rock Mechanics and Mining Sciences, 1997, 34(3–4): 175e1–175.e11

[11] XiaoW, ZhangD, WangX. Experimental study on progressive failure process and permeability characteristics of red sandstone under seepage pressure [J]. Engineering Geology, 2020, 265: 105406

[12] HuaA, YouM. Rock failure due to energy release during unloading and application to underground rock burst control [J]. Tunnelling and Underground Space Technology, 2001, 163241-246

[13] YaoQ, ChenT, TangC, et al. . Influence of moisture on crack propagation in coal and its failure modes [J]. Engineering Geology, 2019, 258105156

[14] ZhangL, CongY, MengF, et al. . Energy evolution analysis and failure criteria for rock under different stress paths [J]. Acta Geotechnica, 2021, 16(2): 569-580

[15] ZhangY, WangL, LiH, et al. . Experimental study of the permeability of fractured sandstone under complex stress paths [J]. Energy Science & Engineering, 2020, 8(9): 3217-3227

[16] YuJ, ChenX, CaiY, et al. . Triaxial test research on mechanical properties and permeability of sandstone with a single joint filled with gypsum [J]. KSCE Journal of Civil Engineering, 2016, 20(6): 2243-2252

[17] ZhangJ, SongZ, WangS. Experimental investigation on permeability and energy evolution characteristics of deep sandstone along a three-stage loading path [J]. Bulletin of Engineering Geology and the Environment, 2021, 80(2): 1571-1584

[18] BieniawskiZ T. Mechanism of brittle fracture of rock [J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1967, 4(4): 395-406

[19] MartinC D, ChandlerN A. The progressive fracture of Lac du Bonnet granite [J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1994, 31(6): 643-659

[20] NaraY, MeredithP G, YonedaT, et al. . Influence of macro-fractures and micro-fractures on permeability and elastic wave velocities in basalt at elevated pressure [J]. Tectonophysics, 2011, 503(1–2): 52-59

[21] GazievE. Rupture energy evaluation for brittle materials [J]. International Journal of Solids and Structures, 2001, 38(42–43): 7681-7690

[22] ChenY, ZuoJ, LiZ, et al. . Experimental investigation on the crack propagation behaviors of sandstone under different loading and unloading conditions [J]. International Journal of Rock Mechanics and Mining Sciences, 2020, 130104310

[23] WangW, LiX, HuD, et al. . Permeability evolution of brittle rock in progressive failure process under triaxial compression [J]. Rock and Soil Mechanics, 2016, 37(10): 2761-2768

[24] KouM, LiuX, TangS, et al. . 3-D X-ray computed tomography on failure characteristics of rock-like materials under coupled hydro-mechanical loading [J]. Theoretical and Applied Fracture Mechanics, 2019, 104102396

[25] LiuS, ZhuQ, ShaoJ. Deformation and mechanical properties of rock: Effect of hydromechanical coupling under unloading conditions [J]. Bulletin of Engineering Geology and the Environment, 2020, 79(10): 5517-5534

[26] MuralhaJ, GrasselliG, TatoneB, et al. . ISRM suggested method for laboratory determination of the shear strength of rock joints: Revised version [J]. Rock Mechanics and Rock Engineering, 2014, 47(1): 291-302

[27] MengF, ZhouH, ZhangC, et al. . Evaluation methodology of brittleness of rock based on post-peak stress–strain curves [J]. Rock Mechanics and Rock Engineering, 2015, 481787-1805

[28] VajdovaV, ZhuW, ChenT M N, et al. . Micromechanics of brittle faulting and cataclastic flow in Tavel limestone [J]. Journal of Structural Geology, 2010, 32(8): 1158-1169

[29] ChenX, FengL, WangJ, et al. . Cyclic triaxial test investigation on tuffs with different water content at Badantoru Hydropower Station in Indonesia [J]. Engineering Geology, 2022, 300106554

[30] WangG, SongL, WangQ, et al. . Experimental study on the mechanical properties, acoustic emission characteristics, and permeability evolution of sandstone under triaxial hydromechanical coupling [J]. Energy Science & Engineering, 2022, 10(12): 4466-4480