Damage characteristics and failure modes of deep sandstone under unloading disturbance: Insights from true triaxial test and DEM simulation

Abstract

This study conducted true triaxial unloading disturbance tests and DEM numerical simulations to elucidate the damage evolution and failure modes of deep rock mass under unloading disturbance conditions. The findings indicated that the DEM-developed Model Predictive Control (MPC) method surpasses conventional servo control in stability of servo speed and boundary stress. During initial loading of intact sandstone under high true triaxial stress, stress-coupling characteristics in intermediate/minimum principal stress directions showed insensitivity to intermediate principal stress; divergence began at yield initiation. Perforated sandstone exhibited consistent failure modes across disturbance amplitudes. Increased disturbance amplitude reduced bearing strength while accelerating damage rates, with sixth-level disturbance accounting for >40% of total damage. Tensile cracks consistently predominated over shear cracks throughout loading; disturbance did not significantly alter their ratio. Secondary loading progressively increased shear crack proportion, peaking at specimen failure. Shear failure dominated perforated sandstone instability. Based on the failure characteristics and strength attenuation laws of perforated sandstone under deep disturbance, control measures for engineering sites are proposed. The research results provide a reference for the application of discrete element method in understanding complex stress paths in deep geotechnical engineering and the damage and failure mechanisms of surrounding rock in deep roadways.

Keywords

unloading and disturbance / DEM servo mechanism / perforated sandstone / disturbance damage / deep roadways

References

[1] Henning J G, Mitri H S. Numerical modelling of ore dilution in blasthole stoping. International Journal of Rock Mechanics and Mining Sciences, 2007, 44(5): 692-703. J]

[2] Ma Z-y, Zuo J-p. Failure mechanisms of roadways with non-coplanar axial direction and stress space: True triaxial test and mechanical analysis. International Journal of Mining Science and Technology, 2024, 34(12): 1711-1725. J]

[3] Wang Y-p, Li G-y, Chen D, et al.Effect of complex cyclic stress path dependency on cumulative plastic strain for frozen soil: Laboratory simulation and model prediction. Acta Geotechnica, 2025, 20(6): 2835-2853. J]

[4] Liu C-y, Zhao G-m, Pan C, et al.Experimental study of rock failure and fractal characteristics under true triaxial unloading. Fractal and Fractional, 2025, 9(3): 182. J]

[5] Liu C-y, Zhao G-m, Xu W-s, et al.Experimental study on failure characteristics of single-sided unloading rock under different intermediate principal stress conditions. International Journal of Mining Science and Technology, 2023, 33(3):275-287. J]

[6] Feng X-t, Gao Y-h, Zhang X-w, et al.Evolution of the mechanical and strength parameters of hard rocks in the true triaxial cyclic loading and unloading tests. International Journal of Rock Mechanics and Mining Sciences, 2020, 131: 104349. J]

[7] Si X-f, Gong F-q. Strength-weakening effect and shear-tension failure mode transformation mechanism of rockburst for fine-grained granite under triaxial unloading compression. International Journal of Rock Mechanics and Mining Sciences, 2020, 131: 104347. J]

[8] Ren F-q, Karakus M, Nguyen G, et al.Effects of pressure relief holes on coal burst: Insights from true-triaxial unloading tests. Journal of Rock Mechanics and Geotechnical Engineering, 2024, 16(9): 3378-3394. J]

[9] Wang C-y, Zhang D-m, Yu B-c, et al.Deformation and seepage characteristics of coal under true triaxial loading - unloading. Rock Mechanics and Rock Engineering, 2023, 56(4): 2673-2695. J]

[10] Liang Y-p, Ran Q-c, Zou Q-l, et al.Experimental study of mechanical behaviors and failure characteristics of coal under true triaxial cyclic loading and unloading and stress rotation. Natural Resources Research, 2022, 31(2): 971-991. J]

[11] Xie H-p, Lu J, Li C-b, et al.Experimental study on the mechanical and failure behaviors of deep rock subjected to true triaxial stress: A review. International Journal of Mining Science and Technology, 2022, 32(5): 915-950. J]

[12] Gao L, Zhang Y, Liu Y-p, et al.Study on the cracking behavior of asphalt mixture by discrete element modeling with real aggregate morphology. Construction and Building Materials, 2023, 368: 130406. J]

[13] Xiao F, Jiang D-y, Wu F, et al.Deformation and failure characteristics of sandstone subjected to true-triaxial unloading: An experimental and numerical study. Fatigue & Fracture of Engineering Materials & Structures, 2021, 44(7): 1862-1882. J]

[14] Zhao Z-h. Gouge particle evolution in a rock fracture undergoing shear: A microscopic DEM study. Rock Mechanics and Rock Engineering, 2013, 46(6): 1461-1479. J]

[15] Duan K, Kwok C Y, Ma X. DEM simulations of sandstone under true triaxial compressive tests. Acta Geotechnica, 2017, 12(3): 495-510. J]

[16] Zheng Z, Li S-x, Zhang Q, et al.True triaxial test and DEM simulation of rock mechanical behaviors, meso-cracking mechanism and precursor subject to underground excavation disturbance. Engineering Geology, 2024, 337: 107567. J]

[17] Zhou X-p, Han L-y, Bi J, et al.Experimental and numerical study on dynamic mechanical behaviors of shale under true triaxial compression at high strain rate. International Journal of Mining Science and Technology, 2024, 34(2): 149-165. J]

[18] Zheng Z, Tang H, Zhang Q, et al.True triaxial test and PFC3D-GBM simulation study on mechanical properties and fracture evolution mechanisms of rock under high stresses. Computers and Geotechnics, 2023, 154: 105136. J]

[19] Yang W-m, Geng Y, Zhou Z-q, et al.True triaxial hydraulic fracturing test and numerical simulation of limestone. Journal of Central South University, 2020, 27(10): 3025-3039. J]

[20] Li Y, Yang S-q, Song Y, et al.Three-dimensional numerical simulation on failure mechanical characteristics of fissured sandstone specimens under true triaxial conditions. Theoretical and Applied Fracture Mechanics, 2024, 131: 104436. J]

[21] Zheng Z, Xu H-y, Zhang K, et al.Intermittent disturbance mechanical behavior and fractional deterioration mechanical model of rock under complex true triaxial stress paths. International Journal of Mining Science and Technology, 2024, 34(1): 117-136. J]

[22] Zhou X-p, Pan X-k, Cheng H. The nonlinear creep behaviors of sandstone under the different confining pressures based on NMR technology. Rock Mechanics and Rock Engineering, 2021, 54(9): 4889-4904. J]

[23] Liu C-y, Zhao G-m, Xu W-s, et al.Experimental investigation on failure process and spatiotemporal evolution of rockburst in granite with a prefabricated circular hole. Journal of Central South University, 2020, 27(10): 2930-2944. J]

[24] Liu C-y, Pan C, Zhao G-m, et al.Experimental study on the failure mechanism of roadway surrounding rock under true triaxial loading: Insights from acoustic emission (AE) characteristics. Measurement, 2025, 246: 116727. J]

[25] Zhang Z-r, Wu S-c, Cheng H-y, et al.Experimental study on the influence of structural planes on rockbursts in deep-buried hard-rock tunnels. Rock Mechanics and Rock Engineering, 2024, 57(10): 8057-8080. J]

[26] Kwiatek G, Martínez-Garzón P, Goebel T, et al.Intermittent criticality multi-scale processes leading to large slip events on rough laboratory faults. Journal of Geophysical Research: Solid Earth, 2024, 129(3): e2023JB028411. J]

[27] Lu G-m, Feng X-t, Li Y-h, et al.Influence of microwave treatment on mechanical behaviour of compact basalts under different confining pressures. Journal of Rock Mechanics and Geotechnical Engineering, 2020, 12(2):213-222. J]

[28] Itasca Consulting GroupPFC^2D/3D (Particle flow code) user’s manual, 2008[M]

[29] Cetinsaya B, Reiners D, Cruz-Neira C. From PID to swarms: A decade of advancements in drone control and path planning - A systematic review (2013–2023). Swarm and Evolutionary Computation2024, 89: 101626. J]

[30] Yilmaz U, Kircay A, Borekci S. PV system fuzzy logic MPPT method and PI control as a charge controller. Renewable and Sustainable Energy Reviews, 2018, 81: 994-1001. J]

[31] Andreaus U, Colloca M, Iacoviello D, et al.Optimal-tuning PID control of adaptive materials for structural efficiency. Structural and Multidisciplinary Optimization, 2011, 43(1): 43-59. J]

[32] Schwenzer M, Ay M, Bergs T, et al.Review on model predictive control: An engineering perspective. The International Journal of Advanced Manufacturing Technology, 2021, 117(5): 1327-1349. J]

[33] Mayne D Q. Model predictive control: Recent developments and future promise. Automatica, 2014, 50(12): 2967-2986. J]

[34] Faulwasser T, Grüne L, Müller M A. Economic nonlinear model predictive control. Foundations and Trends® in Systems and Control, 2018, 5(1): 1-98. J]

[35] Coetzee C J. Review: Calibration of the discrete element method. Powder Technology, 2017, 310: 104-142. J]

[36] Li K-s, Yang S-q, Song Y, et al.Numerical characterization on fracture evolution behavior of pre-flawed sandstone under monotonic and multilevel cyclic loading. Theoretical and Applied Fracture Mechanics, 2024, 133: 104634. J]

[37] O’Sullivan C. Particle-based discrete element modeling: Geomechanics perspective. International Journal of Geomechanics, 2011, 11(6): 449-464. J]

[38] Shang R-p, Yang Y-g, Huang B-x, et al.Calibration and intelligent optimization for DEM numerical parameters in heterogeneous rock mass. Computers and Geotechnics, 2025, 177: 106863. J]

[39] Yang Z, Tao M, Ranjith P G. Novel insights into grain size effect of stressed crystalline rock using weakened grain boundary model. International Journal of Rock Mechanics and Mining Sciences, 2025, 189: 106098. J]

[40] Zheng Z-d, Shi Z-m, Wang M-x, et al.Fatigue fracture and energy evolution characteristics of sandstone under water - ice phase transitions via the discrete element method. Computers and Geotechnics, 2025, 179: 107023. J]

[41] Song Z-x, Zhang J-w, Zhang Y, et al.Characterization and evaluation of brittleness of deep bedded sandstone from the perspective of the whole life-cycle evolution process. International Journal of Mining Science and Technology, 2023, 33(4): 481-502. J]

[42] Song Z-x, Zhang J-w, Wu S-k, et al.Energy driving-damage degradation-structural failure mechanism of layered sandstones under uniaxial conditions. Rock Mechanics and Rock Engineering, 2025, 58(3): 3815-3853. J]

[43] Wang Q, Jiang B, Xu S, et al.Roof-cutting and energy-absorbing method for dynamic disaster control in deep coal mine. International Journal of Rock Mechanics and Mining Sciences, 2022, 158: 105186. J]

[44] Wu S-k, Zhang J-w, Xu Y-l, et al.Study on mechanical properties and application of cement-based materials with different properties under impact load. Construction and Building Materials, 2025, 464: 140227. J]

[45] Wu X-k, Zhao G-m, Meng X-r, et al.Load-bearing characteristics and energy evolution of fractured rock masses after granite and sandstone grouting. Journal of Central South University, 2024, 31(8): 2810-2825. J]

[46] Wang C, Li X-f, Xiong Z-q, et al.Experimental study on the effect of grouting reinforcement on the shear strength of a fractured rock mass. PLoS One, 2019, 14(8):e0220643. J]

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