Research status of sulfoaluminate cement-based material grouting technology for strata disaster control in mining engineering

Abstract

Grouting technology is an important means for controlling strata disasters and has been widely employed in mining engineering. Grouting materials are the core of grouting technology, and numerous types of grouting materials have been developed globally. Among these, the sulfoaluminate cement-based grouting material has achieved excellent results in fractured rocks reinforcement, filling, and water blocking projects due to its high stone strength and rapid growth, adjustable setting time, no sedimentation or segregation of the slurry, simplified operational requirements, and cost-effectiveness. To further promote in-depth research on the grouting technology of sulfoaluminate cement-based materials and its application in strata disaster control fields, this study reviews the research on sulfoaluminate cement-based materials and the grouting process, points out the shortcomings and prospects of current research, and presents our typical engineering application cases of sulfoaluminate cement-based grouting materials.

Keywords

Sulfoaluminate cement-based grouting material / Grouting technology / Strata disaster control / Mining engineering / Research and application status

References

[1] X.K. Wu, G.M. Zhao, X.R. Meng, C.Y. Liu, Z.X. Liu, S.J. Huang, Q.H. Zhang, Load- bearing characteristics and energy evolution of fractured rock masses after granite and sandstone grouting, J. Cent. S. Univ. 31 (8) (2024) 2810-2825, https://doi.org/10.1007/s11771-024-5760-y.

[2] F. Oppong, N. Yao, W.H. Zhang, Y.D. Liu, O. Kolawole, Tentative application of expansive cementitious materials in grouting - a systematic review, Case Stud. Constr. Mater. 18 (2023) e02113, https://doi.org/10.1016/j.cscm.2023.e02113.

[3] X.Y. Yu, S.Y. Lv, Y.F. Luo, P.C. Liu, H. Fu, Y.C. Zhou, Research on support technology for unstable roof roadway under abandoned roadways in ultra-thick coal Seam, Processes 12 (2024) 2886, https://doi.org/10.3390/pr12122886.

[4] I. Sakhno, S. Sakhno, Numerical studies of floor heave mechanism and the effectiveness of grouting reinforcement of roadway in soft rock containing the mine water, Int. J. Rock Mech. Min. Sci. 170 (2023) 105484, https://doi.org/10.1016/j.ijrmms.2023.105484.

[5] W.Q. Zhang, Y. Lei, J.L. Shao, X.A. Wu, S. Li, C.Q. Ma, Simulation of the activation of mining faults and grouting reinforcement under thick loose layer and thin bedrock, Sci. Rep. 12 (2022) 21654, https://doi.org/10.1038/s41598-022-21654-x.

[6] B. Liu, W. Ye, C. Zhu, R. Chen, S. Huang, X. Ni, Analysis on treatment effect of mine tunnel construction Spring in Karst area, Math. Probl Eng. (2021) 1-11, https://doi.org/10.1155/2021/5585054.

[7] J.P. Zhang, L.M. Liu, L. Yang, Mechanism and experiment of self-stress grouting reinforcement for fractured rock mass of underground engineering, Tunn. Undergr. Space Technol. 131 (2023) 104826, https://doi.org/10.1016/j.tust.2022.104826.

[8] S. Huang, G. Zhao, X. Meng, X. Cheng, Q. Gu, G. Liu, S. Zhu, Development of cement-based grouting material for reinforcing narrow coal pillars and engineering applications, Processes 10 (11) (2022) 2292, https://doi.org/10.3390/pr10112292.

[9] S. Liu, Y. Fei, Y. Xu, L. Huang, W. Guo, Full-floor grouting reinforcement for working faces with large mining heights and high water pressure: a case study in China, Mine Water Environ. 39 (2) (2020) 268-279, https://doi.org/10.1007/s10230-020-00683-w.

[10] J. Hou, C. Li, L. Yuan, J. Li, F. Liu, Study on green filling mining technology and its application in deep coal mines: a case study in the Xieqiao coal mine, Front. Earth Sci. 10 (2023), https://doi.org/10.3389/feart.2022.1110093.

[11] H. Song, F. Wei, F. Cheng, D. Duan, H. Wu, Y. Gao, W. Li, Formulation determination and performance study of high-volume fly ash-based grouting fire extinguishing materials, J. Build. Eng. 88 (2024) 109194, https://doi.org/10.1016/j.jobe.2024.109194.

[12] J. Xu, J.D. Jiang, Experiment and application study on high-performance grouting material used to solve the floor heave problem of broken soft rocks, Front. Phys. 10 (2022) 829681, https://doi.org/10.3389/fphy.2022.829681.

[13] Z. Xiang, N. Zhang, D.J. Pan, Z.Z. Xie, Y.M. Zhao, Development and performance characterization of a composite grouting material suitable for sealing and reinforcement of microcracked mudstone, J. Mater. Res. Technol. 26 (2023) 3726-3743, https://doi.org/10.1016/j.jmrt.2023.08.131.

[14] C.W. Zang, L. Yang, M. Chen, Y. Chen, Study of bearing characteristics and damage law of grouting-reinforced bodies, Minerals 13 (2023) 591, https://doi.org/10.3390/min13050591.

[15] W.Q. Zhang, X.X. Zhu, W.M. Lv, Y.J. Wang, S. Li, Research on the preparation and diffusion characteristics of coal seam bottom fracture grouting material based on solid waste synergy, J. Clean. Prod. 422 (2023) 138557, https://doi.org/10.1016/j.jclepro.2023.138557.

[16] M.H. Salimian, A. Baghbanan, H. Hashemolhosseini, M. Dehghanipoodeh, S. Norouzi, Effect of grouting on shear behavior of rock joint, Int. J. Rock Mech. Min. Sci. 98 (2017) 159-166, https://doi.org/10.1016/j.ijrmms.2017.07.002.

[17] Z.P. Yang, X.F. Zhang, X. Liu, X.M. Guan, C.J. Zhang, Y.T. Niu, Flexible and stretchable polyurethane/waterglass grouting material, Constr. Build. Mater. 138 (2017) 240-246, https://doi.org/10.1016/j.conbuildmat.2017.01.113.

[18] S.Y. He, J.X. Lai, L.X. Wang, K. Wang, A literature review on properties and applications of grouts for shield tunnel, Constr. Build. Mater. 239 (2020) 117782, https://doi.org/10.1016/j.conbuildmat.2019.117782.

[19] X. Jiang, H. Zhu, Z. Yan, F. Zhang, F. Ye, P. Li, X. Zhang, Z. Dai, Y. Bai, B. Huang, A state-of-art review on development and progress of backfill grouting materials for shield tunneling, Dev. Built Environ. 16 (2023) 100250, https://doi.org/10.1016/j.dibe.2023.100250.

[20] J.P. Zhang, L.M. Liu, Q.H. Li, W. Peng, F.T. Zhang, J.Z. Cao, H. Wang, Development of cement-based self-stress composite grouting material for reinforcing rock mass and engineering application, Constr. Build. Mater. 201 (2019) 314-327, https:// doi.org/10.1016/j.conbuildmat.2018.12.143.

[21] Y.L. Wang, H.Y. Tang, J.X. Su, H. He, Y.J. Zhao, J.J. Wang, Effect of sodium sulfate and gypsum on performances of expansive grouting material with aluminum as expansion agent, Constr. Build. Mater. 394 (2023) 132212.

[22] L.X. Zhang, J.X. Chen, L.J. Chen, Y.B. Luo, W.W. Liu, F.F. Dong, H. Chen, H.Y. Zhu, Development and application of high-performance grouting materials for anchoring pipe in soft rock tunnel, KSCE J. Civ. Eng. 27 (10) (2023) 4494-4507, https://doi.org/10.1007/s12205-023-0459-4.

[23] X.X. Zhu, Q. Zhang, W.Q. Zhang, J.L. Shao, Z.Y. Wang, X.T. Wu, Experimental study on the basic properties of a green new coal mine grouting reinforcement material, ACS Omega 5 (2020) 16722-16732, https://doi.org/10.1021/acsomega.0c01626.

[24] X. Yu, Preparation and structure analysis of aluminum oxide/water glass/ polyurethane composite grouting material for mining, J. Build. Eng. 76 (2023) 107170, https://doi.org/10.1016/j.jobe.2023.107170.

[25] L. Zhang, M. Su, Y. Wang, Development of the use of sulfo- and ferroaluminate cements in China, Adv. Cement Res. 11 (1) (1999) 15-21, https://doi.org/10.1680/adcr.1999.11.1.15.

[26] Y.J. Liu, Y.M. Xu, C.L. Geng, Sulfoaluminate cement: an alternative to Portland cement, Adv. Mater. Res. 368-373 ( 2011) 478-484. https://dx.doi.org/10.4028/www.scientific.net/amr.368-373.478.

[27] X.F. Liu, P.Z. Pan, Z.Q. Xiong, Y.Y. Zhou, Z. Wang, Sulfoaluminate cement-based double-liquid material grouting in fractured rock, Géotech. Lett. 14 (2) (2024) 1-7, https://doi.org/10.1680/jgele.24.00016.

[28] H.Q. Zhou, C.J. Hou, C.H. Hou, Research and application of stowing material with high water content, J. Coal Sci. Eng. (1) (1992) 25-36.

[29] G.M. Feng, Y. Ding, Research and Application of Ultra-high Water Material Filling Mining Technology[M], China University of Mining and Technology Press, Xuzhou, 2010.

[30] J.W. Zhang, X.M. Guan, H.Y. Li, X.X. Liu, Performance and hydration study of ultra-fine sulfoaluminate cement-based double liquid grouting material, Constr. Build. Mater. 132 (2017) 262-270, https://doi.org/10.1016/j.conbuildmat.2016.11.135.

[31] J.W. Zhang, X.M. Guan, X. Wang, X.W. Ma, Z.X. Li, Z.Y. Xu, B. Jin, Microstructure and properties of sulfoaluminate cement-based grouting materials: effect of calcium sulfate variety, Adv. Mater. Sci. Eng. (1) (2020) 7564108, https://doi.org/10.1155/2020/7564108.

[32] J. Ai, Y.F. Wang, X. Cheng, G.M. Zhao, X.R. Meng, S.J. Huang, Influence of calcination temperature of industrial by-product gypsum on sulphoaluminate cement-based grouting material, Constr. Build. Mater. 478 (2025) 141455, https://doi.org/10.1016/j.conbuildmat.2025.141455.

[33] Z.B. Wang, Y.N. Zhang, Y.R. Fan, J.P. Zuo, W.J. Xu, Synergic effect of steel slag- coal gangue powder on the properties of cementitious grouting materials with SAC modification, Case Stud. Constr. Mater. 23 (2025) e05271, https://doi.org/10.1016/j.cscm.2025.e05271.

[34] H.Y. Li, K. Yang, X.M. Guan, Properties of sulfoaluminate cement-based grouting materials modified with LiAl-layered double hydroxides in the presence of PCE superplasticizer, Constr. Build. Mater. 226 (2019) 399-405, https://doi.org/10.1016/j.conbuildmat.2019.07.210.

[35] J.J. Wang, Y.L. Wang, J. Yu, L. Xu, M.L. Li, J.H. Cheng, Z. Li, Effects of sodium sulfate and potassium sulfate on the properties of calcium sulfoaluminate (CSA) cement based grouting materials, Constr. Build. Mater. 353 (2022) 129045, https://doi.org/10.1016/j.conbuildmat.2022.129045.

[36] J.R. Wang, H.B. Zhang, Y. Zhu, Z.X. Yan, H.C. Chai, Acrylamide in-situ polymerization of toughened sulphoaluminate cement-based grouting materials, Constr. Build. Mater. 319 (2022) 126105, https://doi.org/10.1016/j.conbuildmat.2021.126105.

[37] H.B. Zhang, R. Zhou, S.H. Liu, Y. Zhu, S. Wang, J.R. Wang, X.M. Guan, Enhanced toughness of ultra-fine sulphoaluminate cement-based hybrid grouting materials by incorporating in-situ polymerization of acrylamide, Constr. Build. Mater. 292 (2021) 123421, https://doi.org/10.1016/j.conbuildmat.2021.123421.

[38] X.M. Guan, X.F. Li, H.B. Zhang, Z.P. Yang, H.Y. Li, H.F. Di, L. Zhang, Research and application of inorganic and organic composite grouting reinforcement materials in deep weak rock, Coal Sci. Technol. 51 (8) (2023) 1-11, https://doi.org/10.13199/j.cnki.cst.2023-0216.

[39] X.H. Song, Mechanism Analysis of bolt-grouting Reinforcement for Soft Rock Roadways and Determination of Reasonable Grouting Time[D], Shandong University of Science and Technology, Jinan, 2006, pp. 2-50.

[40] Y.L. Lu, L.G. Wang, B. Zang, Y.J. Li, Optimization of bolt-grouting time for soft rock roadway, Rock Soil Mech. 33 (5) (2012) 1395-1401, https://doi.org/10.16285/j.rsm.2012.05.023.

[41] Q.B. Meng, L.J. Han, Q. Wang, J. Zhang, J.D. Fan, J.W. Nie, S.Y. Wen, Optimization analysis of grouting timing in deep and high stress soft rock roadway, Journal of Central South University (Science and Technology) 48 (10) (2017) 2765-2776, https://doi.org/10.11817/j.issn.1672-7207.2017.10.029.

[42] X.Y. Yu, J.H. Xie, Y.J. Wu, Y.J. Wu, Q.H. Wu, Z.Z. Zhang, H. Wu, A dynamic numerical simulation on the grouting timing in retained rib of pillarless mining, Appl. Sci. 13 (2023) 9479, https://doi.org/10.3390/app13169479.

[43] H.P. Kang, W.Z. Li, F.Q. Gao, J.W. Yang, Grouting theories and technologies for the reinforcement of fractured rocks surrounding deep roadways, Deep Underground Science and Engineering 2 (1) (2023) 2-19, https://doi.org/10.1002/dug2.12026.

[44] H.P. Kang, J.W. Yang, P.F. Jiang, F.Q. Gao, W.Z. Li, J.F. Li, H.Y. Chen, Theory, technology and application of grouted bolting in soft rock roadways of deep coal mines, International Journal of Minerals, Metallurgy and Materials 31 (2024) 1463-1479, https://doi.org/10.1007/s12613-024-2906-8.

[45] S.X. Zhou, H.B. Li, Study on rib spalling cause and control technology of high cutting island coal mining face, Coal Sci. Technol. 45 (5) (2017) 98-102, https:// doi.org/10.13199/j.cnki.cst.2017.05.017.

[46] Y.C. Zhang, Grouting Technology[M], China Coal Industry Publishing House, Beijing, 2012.

[47] Z.F. Zhang, H.P. Kang, Z.Y. Jiang, W.Z. Li, P.F. Jiang, R.C. Cai, Y.T. Zhu, J. Wang, Study and application of high-pressure splitting grouting modification technology in coalmine with depth more than 1 000 m, J. China Coal Soc. 45 ( 2020) 972-981, https://doi.org/10.13225/j.cnki.jccs.SJ19.1545.

[48] J. Rafi, H. Stille, A method for determining grouting pressure and stop criteria to control grout spread distance and fracture dilation, Tunn. Undergr. Space Technol. 112 (2021) 103885, https://doi.org/10.1016/j.tust.2021.103885.

[49] J. Wang, J. Ma, K.M. Yang, S.Y. Yao, X.Y. Shi, Effects and laws analysis for the mining technique of grouting into the overburden bedding separation, J. Clean. Prod. 288 (4) (2020) 125121, https://doi.org/10.1016/j.jclepro.2020.125121.

[50] H.T. Liu, Y. Chen, Z.J. Han, Q.Y. Liu, Z.L. Luo, W.C. Cheng, H.K. Zhang, S.Z. Qiu, H. Z. Wang, Coal wall spalling mechanism and grouting reinforcement technology of large mining height working face, Sensors 22 (2022) 8675, https://doi.org/10.3390/s22228675.

[51] Y. Yu, J.B. Bai, S.J. Zhang, Y.H. Guo, L.Y. Zhang, Disaster mechanism of surrounding rock with double wing mining roadway group and its repair and reinforcement system, J. Min. Saf. Eng. 37 (6) (2020) 1133-1141, https://doi.org/10.13545/j.cnki.jmse.2020.06.007.

[52] X.M. Du, Z.H. Li, H.Y. Fang, B. Li, X.H. Zhao, K.J. Zhai, B.H. Xue, S.H. Wang, A state-of-the-art review on the study of the diffusion mechanism of fissure grouting, Appl. Sci. 14 (6) (2024) 2540, https://doi.org/10.3390/app14062540.

[53] W.Q. Ding, C. Duan, Q.Z. Zhang, Experimental and numerical study on a grouting diffusion model of a single rough fracture in rock mass, Appl. Sci. 10 (20) (2020) 7041, https://doi.org/10.3390/app10207041.

[54] X.X. Zhu, W.Q. Zhang, Y.J. Wang, W.M. Lv, C.Q. Ma, Diffusion mechanism of solid waste product utilization pulping and fracture network grouting, Constr. Build. Mater. 408 (2023) 133571, https://doi.org/10.1016/j.conbuildmat.2023.133571.

[55] Z. Han, S. Chen, C. Wang, C. Wang, S. Hu, Grouting effect evaluation of fractured rock mass based on borehole televiewer observation, IOP Conf. Ser. Earth Environ. Sci. 861 (2) (2021) 022034, https://doi.org/10.1088/1755-1315/861/2/022034.

[56] G.B. Zhang, S.A. Zhang, W. Jia, X. Zhang, Y. Zhang, H.Y. Lian, X.H. Lian, H.L. Fang, Grouting solidification technology for fractured soft coal seams and its application in coalbed methane (coal mine gas) extraction, Front. Energy Res. 11 (2023), https://doi.org/10.3389/fenrg.2023.1338715.

[57] H.R. Bai, J.J. Li, Evaluation of grouting effect detection in goaf, Appl. Mech. Mater. 438 (2013) 1080-1083. https://doi.org/10.4028/www.scientific.net/amm.438-439.1080.

[58] F. Jorne, F.M.A. Henriques, L.G. Baltazar, Evaluation of consolidation of grout injection with ultrasonic tomography, Constr. Build. Mater. 66 (2019) 494-506, https://doi.org/10.1016/j.conbuildmat.2014.05.095.

[59] Q. Wang, H.K. Gao, H.C. Yu, B. Jiang, B.H. Liu, Method for measuring rock mass characteristics and evaluating the grouting-reinforced effect based on digital drilling, Rock Mech. Rock Eng. 52 (2019), https://doi.org/10.1007/s00603-018-1624-9.

[60] X.L. Wang, R.W. Li, Z.W. Liu, D.P. Jiang, Z.G. Ji, Comprehensive evaluation of the reinforcement effect of grouting in broken surrounding rock in deep roadways, Geotech. Geol. Eng. 40 (5) (2022) 2443-2454, https://doi.org/10.1007/s10706-021-02037-x.

[61] W.X. Li, J.T. Chen, J. Zhu, X.B. Ji, Z.Q. Fu, Research on factor analysis and method for evaluating grouting effects using machine learning, Sci. Rep. 14 (2024), https://doi.org/10.1038/s41598-024-57837-x.

[62] Y.F. Liu, Construction of grading system of grouting effect in coalmine roadway based on multi-index comprehensive evaluation, Eng. Appl. Sci. 10 (4) (2025) 75-83, https://doi.org/10.11648/j.eas.20251004.11.

[63] F. Tong, J. Yang, C.Z. Zheng, L. Cheng, X.F. Ma, G.C. Li, Research on the comprehensive evaluation of grouting quality based on fuzzy rock engineering system and variable fuzzy set theory, Int. J. Fuzzy Syst. 25 (3) (2022) 1191-1212, 1007/s40815-022-01433-6.

[64] L. Nie, P. Jing, S. Jia, Z.Q. Li, S. Li, An integrated in-situ evaluation grouting method based on multi-parameter fusion of probe drilling, water pressure tests, and horizontal cross-hole resistivity tomography, Tunn. Undergr. Space Technol. 171 (2026) 107480, https://doi.org/10.1016/j.tust.2026.107480.

[65] X.F. Liu, Z.Q. Xiong, C.W. Liu, C. Wang, Z.P. Xiong, Comprehensive bolt and grouting control technology of mine roadway floor heave with new type grouting material, Coal Sci. Technol. 44 (11) (2016) 24-29.

[66] L.M. Hu, Y.H. Zhang, Z.Q. Xiong, Gob-side entry retaining technology of 4311 fully-mechanized caving face in chengzhuang coal mine, Saf. Coal Mine 46 (9) (2015) 144-147, https://doi.org/10.13347/j.cnki.mkaq.2015.09.041.

[67] C. Wang, Y. Wang, Z.Q. Xiong, C. Wang, Support technology of backfill pillar in parallel goaf roadway with large cross-section in super long working face, J. Min. Saf. Eng. 38 (4) (2021) 739-748, https://doi.org/10.13545/j.cnki.jmse.2020.0407.

[68] X. Yao, S. Wu, C. Ren, W. Wang, Preparing sulfoaluminate cement using phosphogypsum as the only calcium oxide source: effects of fluoride impurities, Constr. Build. Mater. 416 (2024) 135296, https://doi.org/10.1016/j.conbuildmat.2024.135296.

[69] Y. Peng, X. Miao, D. Gao, C. Fan, Preparation, hydration characteristics, and carbon footprint assessment of sulfoaluminate cement prepared by Co-Utilization of industrial solid wastes and bauxite, Materials 19 (10) (2026) 2122, https://doi.org/10.3390/ma19102122.

[70] H.B. Amare, W. Shen, M.A. Gebreyohannes, G. Wang, S. Yixin, W. Zhang, J. Ye, Preparation of calcium sulfoaluminate clinker with raw granular steel slag and phosphogypsum: phase analysis, strength, and microstructure, Constr. Build. Mater. 499 (2025) 144071, https://doi.org/10.1016/j.conbuildmat.2025.144071.

[71] X. Wang, M.-Z. Guo, G. Yue, Q. Li, T.-C. Ling, Synthesis of high belite sulfoaluminate cement with high volume of mixed solid wastes, Cement Concr. Res. 158 (2022) 106845, https://doi.org/10.1016/j.cemconres.2022.106845.

[72] H. Zhang, X. Zhang, Z. Guo, H. Chai, Optimization of the injection and physical properties of sulfoaluminate cement via the in situ polymerization of acrylamide, Buildings 12 (12) (2022) 2237, https://doi.org/10.3390/buildings12122237.

[73] Y. Ai, Y. Xue, F. Kong, B. Zhou, J. Duan, L. Lu, Interfacial enhancement of low- carbon cement-epoxy composite grouts using surface-modified nanosilica: a multiscale experimental and molecular simulation study, Case Stud. Constr. Mater. 24 (2026) e05798, https://doi.org/10.1016/j.cscm.2026.e05798.

[74] J.P. Zhang, K.S. Li, Y. Li, C.X. Liu, J.H. Xu, J.P. He, Applying novel Micro-Nano- Siliceous grouting material improves mechanical behaviors of fractured rock masses and microscopic characteristics of slurry-rock interface: experimental and numerical simulation investigations, Rock Mech. Rock Eng. 57 (10) (2024) 8297-8321, https://doi.org/10.1007/s00603-024-03924-4.

[75] T. Zhao, W. Guo, D. Zhang, Y. Tan, Y. Yin, Y. Tan, Y. Jiang, J. Yao, Theoretical framework for stress relief-support reinforcement cooperative control of rock bursts in deep coal mining, Geohazard Mechanics 2 (1) (2024) 49-57, https://doi.org/10.1016/j.ghm.2024.02.001.

[76] C. Li, Y. Zhao, H. Xue, J. Wu, W. Ma, S. Shen, Y. Gao, H. Lu, Research and application of active support and pressure relief protection in deep mines, Geotech. Geol. Eng. 40 (4) (2021) 2157-2165, https://doi.org/10.1007/s10706-021-02018-0.

[77] M. Ghorbani, K. Shahriar, M. Sharifzadeh, R. Masoudi, A critical review on the developments of rock support systems in high stress ground conditions, Int. J. Min. Sci. Technol. 30 (5) (2020) 555-572, https://doi.org/10.1016/j.ijmst.2020.06.002.

[78] J. Wang, H. Zhou, M. Lu, L. Zhang, Z. Wang, H. Li, T. Mao, F. Shi, D. Xue, Accurate characterization and fractal analysis of pore-fracture evolution in deep coal under temperature effect, Fuel 408 (2026) 137534, https://doi.org/10.1016/j.fuel.2025.137534.

[79] Y. Liu, K. Wei, A. Wang, Q. Fang, C. Wang, Dynamic permeability response and pore-fracture structure evolution of deep coal reservoirs under stress release, Nat. Resour. Res. 34 (2) (2024) 953-982, https://doi.org/10.1007/s11053-024-10418-1.

[80] X. Du, J. Xue, L. Yu, W. Lei, H. Ma, C.-R. Cao, C.-M. Shu, Y. Li, Coal damage and energy characteristics during shallow mining to deep mining, Energy 291 (2024) 130375, https://doi.org/10.1016/j.energy.2024.130375.

[81] L. Gu, Y. Zhou, Y. Xiao, Y. Zhang, Z. Wang, Effect of initial stress difference on hard rock fracture mechanism under true triaxial excavation unloading stress paths, Rock Mech. Rock Eng. 57 (12) (2024) 10205-10227, https://doi.org/10.1007/s00603-024-04090-3.

[82] Y. Wang, F. Chen, Y. Li, X. Sun, N. Liu, Effect of confining pressure unloading rate on mechanical and energy characteristics of coal-rock combinations, Geotech. Geol. Eng. 42 (3) (2023) 2259-2270, https://doi.org/10.1007/s10706-023-02672-6.