Abstract
To address the intense stress evolution and severe floor heave in roadways of extra-thick coal seams, this study investigates the catastrophic evolution laws and mechanisms of medium-hard floor strata using the 122,110 working face of Caojiatan Coal Mine as the engineering background. By integrating field monitoring, theoretical analysis, and numerical simulation, the research challenges the traditional perception of damage caused by a single load and reveals that the “low-level stepped rock beam + high-level articulated rock block” composite load-bearing system, formed after mining, is the root cause of the extreme stress imbalance between the coal pillar side and the solid coal side. The study identifies the non-symmetric evolution characteristics of the roadway driven by a “non-symmetric stress gradient”: the stress on the coal pillar side (26.62 MPa) significantly exceeds that on the solid coal side (22.07 MPa) by approximately 20.6%. This imbalance results in an average maximum floor heave of 473 mm, with the peak heave position shifting markedly toward the solid coal side. A mechanical model and criteria for the non-symmetric stress gradient under the influence of lateral overburden structures were constructed. The dynamic process of “high-pressure extrusion” and its coupling with non-symmetric shear paths in the floor rock mass—driven by the intense “stress potential difference” between the central destressed zone and the high-stress zones on both ribs—was elucidated. Consequently, a synergistic control theory featuring “pressure relief at the structural source, blockage of the stress transmission path, and non-symmetric reinforced support” is proposed. These findings provide a novel theoretical perspective and technical support for managing floor heave in high-stress roadways of extra-thick coal seams.
Similar content being viewed by others
Data availability
The datasets used to support the findings of this study are included in the article. Additional raw monitoring data from the Caojiatan Coal Mine are available from the corresponding author upon reasonable request.
References
He, M. C., Wang, Q. & Wu, Q. Y. Innovation and future of mining rock mechanics. Rock. Mech. Geotechn. Eng. 13 (01), 1–21 (2021).
Sakhno, I. G., Sakhno, S. V. & Kamenets, V. I. Stress environment around head entries with pillarless gobside entry retaining through numerical simulation incorporating the two type of filling wall. IOP Conf. Ser: Earth Environ. Sci. 1049 (01), 012011 (2022).
Xue, Y. P. Optimization of small coal pillar width and control measures in gob-side entry excavation of thick coal seams. Sci. Rep. 14, 23304 (2024).
Zhang, Z. Y., Shimada, H., Sasaoka, T. & Hamanaka, A. Stability control of retained goaf-side gateroad under different roof conditions in deep underground Y type longwall mining. Sustainability 9 (10), 1671 (2017).
Wang, M. et al. Stability control of overburden and coal pillars in the gob-side entry under dynamic pressure. Int. J. Rock. Mech. Min. Sci. 170, 105490 (2023).
Yu, Y. X. et al. A calculation method of reasonable size of coal pillar in large mining height section based on elastic theory. Coal Sci. Technol. 51 (3), 37–51 (2023).
Zhang, Y. et al. Study on floor heave failure mechanism and control countermeasures of deep buried soft rock roadway. Coal Eng. 54 (12), 50–55 (2022).
Yu, F. H., Yang, J., Zhou, K. & Liu, B. D. Mechanism and control measures for floor heave in gob-side entry of weakly cemented soft rock. Sci. Rep. 15, 33578 (2025).
Zhang, J. et al. X. Study on roadway roof deformation and coal pillar energy accumulation instability. Sci. Rep. 14, 27603 (2024).
Qin, D. D., Wang, X. F., Zhang, D. S. & Chen, X. Y. Study on surrounding rock-bearing structure and associated control mechanism of deep soft rock roadway under dynamic pressure. Sustainability 11 (7), 1892 (2019).
Cheng, H. et al. X. Research on floor heave mechanism and prevention technology of mining roadway in close-distance coal seams. J. Cent. South. University(Sci Technol). 53 (4), 1392–1405 (2022).
Yu, B. et al. Directional fracturing technology of compound blasting in hard roof and its engineering application. J. China Coal Soc. 48 (1), 126–138 (2023).
Han, G., Wang, Q. & Lyu, Y. L. Study on the influence mechanism of section coal pillar on dynamic manifestation of gob-side entry. Coal Sci. Technol. 50 (S2), 153–159 (2022).
Zhai, W. L. et al. Effect of roof cutting on protecting gob-side coal roadway with narrow coal pillar in extra-thick coal seam with fully mechanized top-coal caving mining and surrounding rock control. J. Min. Saf. Eng. 42 (6), 1252–1268 (2025).
Hui, Z. L., Zhao, Z. Q., Wei, X. X. & Li, Y. The energy and stress evolution law of surrounding rock in gob side entry driving of adjacent mining faces. Sci. Rep. 15, 34488 (2025).
Xue, H. J. et al. Research on deformation mechanisms and control technology for floor heave in deep dynamic pressure roadway. Appl. Sci. 15 (15), 8125 (2025).
Kang, H. P. & Gao, F. Q. Stress evolution and surrounding rock control in coal mining. Chin. J. Rock. Mech. Eng. 43 (1), 1–40 (2024).
Fu, Y. P., Ren, Y. M., He, Y. L. & Li, C. T. Mechanism and control technology of roadway floor heave deformation and failure under the influence of repeated mining in multiple coal seams. Sci. Rep. 15, 31415 (2025).
Gao, Y. B. et al. Deformation mechanism and pressure relief control of surrounding rock in gob-side roadway under dynamic pressure in extra-thick coal seam with fully mechanized top-coal caving mining. Coal Sci. Technol. 51 (2), 83–94 (2023).
Li, T. X., Hao, B. Y. & Shi, C. Y. Study on the Mechanisms of Floor Heave in Roadways and Control Strategies via Grooving and Pressure Relief. Processes 13 (6), 1642 (2025).
Sakhno1, I. et al. Floor Heave Control in Gob-Side Entry Retaining by Pillarless Coal Mining with Anti-Shear Pile Technology. Appl. Sci. 14 (12), 4992 (2024).
Wang, S. Y. Current Status of The Mechanism of Floor Heave in Deep Tunnels. Front. Sci. Eng. 5, 3 (2025).
Hua, X. Z., Li, C., Liu, X., Yang, P. & Chen, X. Y. Mechanism and prevention of floor heave in roof-cutting entry retaining of deep mines. J. Rock. Soil. Mech. 46 (3), 955–968 (2025).
Xu, X. D. Research on the manifestation mechanism and pressure relief control of strong mine pressure in the gob-side entry of the extra-thick coal seam in Caojiatan Mine. Chin. J. Rock. Mech. Eng. 42 (12), 3120 (2023).
Acknowledgements
The authors would like to thank Pengkun Luo and Xiaogang Zhang for their technical support during the experiments. We are also grateful to Caojiatan Coal Mine for providing the research site and for the assistance offered during the field investigation and data collection process.
Funding
This study was supported by the National Natural Science Foundation of China (Young Scientists Fund) (Grant No. 52404144) and the Natural Science Basic Research Program of Shaanxi Province (Grant No. 2024JC-YBQN-0594).
Author information
Authors and Affiliations
Contributions
J.Z. supervised the research and conceptualized the framework. J.S. conducted data collection and prepared the original manuscript. S.G. and Y.H. assisted in data collection and provided writing guidance. B.W., T.Y., G.Q., and Y.Z. participated in the project and data processing. All authors have read and agreed to the published version of the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
About this article
Cite this article
Zhang, J., Sun, J., Wang, B. et al. Mechanism and control strategies for asymmetric floor heave in extra-thick coal seam roadways under high stress. Sci Rep (2026). https://doi.org/10.1038/s41598-026-45203-y
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598-026-45203-y
