Influence of Moisture on Mechanical Properties and Energy Dissipation Characteristics of Coal–Rock Combined Body
Source abstract
Abstract
Focusing on underground reservoir coal pillar dams subjected to long-term water immersion, this study employed a self-developed non-destructive water saturation apparatus to prepare monolithic and composite coal–rock specimens with varying moisture conditions. Through uniaxial compression tests combined with acoustic emission (AE) monitoring technology, the mechanical failure characteristics and energy dissipation behavior of these specimens were systematically investigated. The results indicated that both the UCS and elastic modulus (E) of the single-rock specimens decreased with increasing water content. Conversely, the mechanical properties of the composite specimens were significantly influenced by the properties and water saturation state of the rock components within the composite. When the rocks within the composite specimens share identical moisture conditions, higher rock strength correlates with greater specimen strength and strain. Under identical lithological conditions, the peak stress (σc), peak strain (εc), and elastic modulus (E) of the composite specimens decreased with increasing rock moisture content, which exhibited reductions of 45%, 21.8%, and 13.5% in σc, εc, and E, respectively, under saturated conditions. Acoustic emission (AE) monitoring data revealed that AE events in coal–rock composite specimens under uniaxial loading exhibited distinct spatial distribution patterns. Furthermore, as the rock moisture content increased, the ultimate failure mode of the composite specimen progressively shifted from shear failure within the coal matrix toward tensile failure of the composite as a whole. An analysis of the energy characteristics of coal–rock composite specimens under uniaxial compression revealed that rock properties and moisture content significantly influence energy absorption and conversion during loading. With increasing rock moisture content, the total energy, elastic strain energy, and dissipated energy at the peak load exhibited decreasing trends, reflecting the weakening effect of water on energy dissipation in coal–rock composites. This study systematically investigated the instability mechanisms of coal–rock composites from three perspectives—mechanical properties, failure modes, and energy dissipation—thereby providing valuable insights for evaluating the long-term stability of underground reservoir coal pillar dams subjected to prolonged water immersion.
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Research context
OpenAlex topics: Rock Mechanics and Modeling · Tailings Management and Properties · Dam Engineering and Safety
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
School of Mins, China University of Mining and Technology, Xuzhou 221116, China
Yunlong Lake Laboratory of Deep Underground Science and Engineering, Xuzhou 221116, China
Funding
National Natural Science Foundation of China · Natural Science Foundation of Jiangsu Province
References (59)
Show source-provided references
1. Potential for mine water disposal in coal seam goaf: Investigation of storage coefficients in the Shendong mining area10.1016/j.jclepro.2019.118646 ↗
2. Chen, Y.M., Zhang, Y., Xia, F., Xing, Z., and Wang, L.C. (2022). Impacts of Underground Reservoir Site Selection and Water Storage on the Groundwater Flow System in a Mining Area-A Case Study of Daliuta Mine. Water, 14.10.3390/w14203282 ↗
3. Ultimate water level and deformation failures of the artificial dam in the coal mine underground reservoir10.1016/j.engfailanal.2024.108367 ↗
4. The Taguchi approach to the evaluation of the influence of different testing conditions on the mechanical properties of rock10.1007/s12665-013-2938-2 ↗
5. Impact of Water Saturation on the Anisotropic Elastic Moduli of a Gas Shale10.1007/s00603-025-04397-9 ↗
6. Advances in the understanding of the role of degree of saturation and water distribution in mechanical behaviour of calcarenites using magnetic resonance imaging technique10.1016/j.conbuildmat.2021.124420 ↗
7. Skrzypkowski, K., Zagórski, K., and Zagórska, A. (2021). Determination of the Extent of the Rock Destruction Zones around a Gasification Channel on the Basis of Strength Tests of Sandstone and Claystone Samples Heated at High Temperatures up to 1200 °C and Exposed to Water. Energies, 14.10.3390/en14206464 ↗
8. Gad, A., Arman, H., Yagiz, S., Abdelghany, O., Amin, B.M., Ahmed, A., Paramban, S., and Saima, M.A. (2025). Strength characterization of limestone lithofacies under different moisture states. Sci. Rep., 15.10.1038/s41598-025-22699-4 ↗
9. Tracer Test Method to Confirm Hydraulic Connectivity Between Goafs in a Coal Mine10.1007/s10230-024-00972-8 ↗
10. Chen, Z.H., Zhao, X.D., Han, Z., Ji, Y., and Qiao, Z.J. (2023). Reasonable Size Design and Influencing Factors Analysis of the Coal Pillar Dam of an Underground Reservoir in Daliuta Mine. Processes, 11.10.3390/pr11072006 ↗
11. Zhu, H., Wang, P., Zhang, K., Gao, Y., Qi, Z., and Cai, M. (2025). Influence of Water Immersion on Coal Rocks and Failure Patterns of Underground Coal Pillars Considering Strength Reduction. Appl. Sci., 15.10.3390/app15126700 ↗
12. Study on Two-Body Mechanical Model Based on interaction Between Structural Body and Geo-Body
13. Rock burst tendency of coal-rock combinations sample
14. New approaches to testing and evaluating the impact capability of coal seam with hard roof and/or floor in coal mines
15. Mechanical Characteristics and Energy Dissipation Trends of Coal-Rock Combination System Samples with Different Inclination Angles under Uniaxial Compression10.1155/2021/7702751 ↗
16. The strength characteristics and progressive failure mechanism of soft rock-coal combination samples with consideration given to interface effects10.1016/j.ijrmms.2020.104593 ↗
17. Acoustic Emission (AE) Based Damage Quantification and Its Relation with AE-Based Micromechanical Coupled Damage Plasticity Model for Intact Rocks10.1007/s00603-023-03686-5 ↗
18. Study on mechanical properties and deformation of coal specimens under different confining pressure and strain rate10.1016/j.tafmec.2022.103287 ↗
19. Mechanical properties and energy migration mechanisms of coal-rock composite with different height ratios under gas-containing conditions10.1016/j.jmrt.2025.05.036 ↗
20. Failure behavior of a rock-coal-rock combined body with a weak coal interlayer10.1016/j.ijmst.2013.11.005 ↗
21. Research on AE and EMR response law of the driving face passing through the fault10.1016/j.ssci.2019.04.021 ↗
22. Li, X.B., Liu, X.S., Tan, Y.L., Ma, Q., Wu, B.Y., and Wang, H.L. (2022). Creep Constitutive Model and Numerical Realization of Coal-Rock Combination Deteriorated by Immersion. Minerals, 12.10.3390/min12030292 ↗
23. Effects of water intrusion and loading rate on mechanical properties of and crack propagation in coal–rock combinations10.1007/s11771-017-3444-6 ↗
24. Damage Effect and Deterioration Mechanism of Mechanical Properties of Fractured Coal-Rock Combined Body Under Water-Rock Interaction10.1007/s00603-024-04163-3 ↗
25. Water-bearing effect on mechanical properties and interface failure mode of coal-rock combination samples10.1177/01445987231151254 ↗
26. Experimental study on dynamic mechanical responses of coal specimens under the combined dynamic-static loading10.1007/s12517-020-05985-5 ↗
27. Energy Distribution Law of Dynamic Failure of Coal-Rock Combined Body
28. Seismic effort of blasting wave transmitted in coal-rock mass associated with mining operation10.1007/s11771-012-1317-6 ↗
29. Study progress of failure behaviors and nonlinear model of dee pcoal-rock combined body
30. Mechanical properties and damage constitutive model of coal in coal-rock combined body10.1016/j.ijrmms.2018.07.020 ↗
31. Numerical investigation on crack development and energy evolution of stressed coal-rock combination10.1016/j.ijrmms.2020.104417 ↗
32. Cai, Y.B., Zhou, X., Wang, L., Fu, Q., and Li, Q.X. (2025). Mechanical Damage Characteristics and Energy Evolution Laws of Primary Coal-Rock Combinations with Different Coal-Rock Ratios. Appl. Sci., 15.10.3390/app15063091 ↗
33. Yu, Y.J., Liu, J.J., Yang, Y.T., Wang, P.D., Wang, Z.M., Song, Z.Y., Liu, J.M., and Zhao, S.Q. (2022). Failure energy evolution of coal-rock combination with different inclinations. Sci. Rep., 12.10.1038/s41598-022-23813-6 ↗
34. Zhao, P., Jin, Q., Li, S., Lin, H., Zhou, R., Lei, W., Ma, X., and Yuan, X. (2025). Evolution of static fracture mechanics and energy dissipation characteristics of composites based on different interface angles. Sci. Rep., 15.10.1038/s41598-025-89099-6 ↗
35. Influence of Rock Strength on the Mechanical Characteristics and Energy Evolution Law of Gypsum-Rock Combination Specimen under Cyclic Loading-Unloading Condition10.1061/(ASCE)GM.1943-5622.0002276 ↗
36. Dynamic multifractal characteristics of acoustic emission about composite coal-rock samples with different strength rock10.1016/j.chaos.2022.112725 ↗
37. Effects of combination mode on mechanical properties of bi-material samples consisting of rock and coal10.1016/j.jmrt.2022.05.174 ↗
38. Study on mechanical property and electromagnetic emission during the fracture process of combined coal-rock10.1016/j.proeps.2009.09.045 ↗
39. Research on strength and failure mechanism of deep coal-rock combination bodies of different inclined angles
40. Frictional sliding tests on combined coal-rock samples10.1016/j.jrmge.2014.03.007 ↗
41. Influence of rock strength on the mechanical behavior and P-velocity evolution of coal-rock combination specimen10.1016/j.jmrt.2021.03.059 ↗
42. Effect of coal thicknesses on energy evolution characteristics of roof rock-coal-floor rock sandwich composite structure and its damage constitutive model10.1016/j.compositesb.2020.108086 ↗
43. Simulation Study on Strength and Failure Characteristics of Coal-Rock Composite Sample with Coal Persistent Joint
44. Deformation failure characteristics of coal-rock combined body under uniaxial compression: Experimental and numerical investigations10.1007/s10064-018-1336-0 ↗
45. The Effect of Crack Characteristics on The Mechanical Properties and Energy Characteristics of Coal-Rock Composite Structure
46. Experimental study on the moisture migration and triaxial mechanical damage mechanisms of water-bearing coal samples10.1016/j.ijrmms.2022.105263 ↗
47. Mechanical properties and damage constitutive model of coal specimen with different moisture under uniaxial loading
48. Influence of moisture on crack propagation in coal and its failure modes10.1016/j.enggeo.2019.105156 ↗
49. Effects of Moisture Content and Loading Rate on Coal Samples: Mechanical Properties and Failure Mechanisms10.1007/s00603-024-04247-0 ↗
50. Failure characteristics and energy properties of red sandstone under uniaxial compression: Water content effect and its application10.1007/s10064-025-04085-6 ↗
51. Energy evolution mechanism and failure criteria of jointed surrounding rockunder uniaxial compression10.1007/s11771-021-4735-5 ↗
52. Energy evolution of coal at different depths under unloading conditions10.1007/s00603-019-01856-y ↗
53. Researches on the ability of rocks to accumulate elastic energy and rock bursting. Part I. Coefficients of the ability of rocks to accumulate elastic energy WE and rock bursting PES
54. Criteria for strength and structural failure of rocks based on energy dissipation and energy release principles
55. An energy-based method for uniaxially compressed rocks and its implication10.1016/j.jrmge.2024.07.002 ↗
56. Numerical simulation of microstructure of brittle rock using a grain-breakable distinct element grain-based model10.1016/j.compgeo.2016.05.019 ↗
57. Hao, T.X., Wang, G.Q., Li, F., Tang, Y.J., and Yuan, M.Q. (2024). Study on the characteristics of acoustic-thermal precursors of destabilization damage in coal-rock combination bodies with different proportions. Sci. Rep., 14.10.1038/s41598-024-77170-7 ↗
58. Review on the Research Progress of Dynamic Failure Response of Coal-Rock Combined Body
59. Xia, H.J., Zhang, H.M., and Zhang, J.F. (2023). Research on Damage Mechanism and Mechanical Characteristics of Coal Rock under Water Immersion. Sustainability, 15.10.3390/su151713095 ↗