Mechanical Behavior of Gas-Transmission Pipeline in a Goaf
2. Finite-Element Model of Pipe–Soil Interactions in Mined-Out Conditions
2.1. Finite-Element Model Parameters
2.2. Soil Model of Each Rock Stratum
2.3. Pipeline Model
2.4. Finite-Element Model of Pipe–Soil Interaction
2.5. Validation of the Finite-Element Model
- Grid verification
- Comparison of the finite-element analysis results with theoretical values
3. Influencing Factors on the Mechanical Behavior of a Buried Pipeline in the Goaf
3.1. Effect of the Horizontal Angle
3.2. Effect of Friction Coefficient
3.3. Effect of Coal-Seam Dip Angle
- The equivalent stress of the pipeline increases when the horizontal angle of inclination is reduced, whereas the maximum equivalent stress occurs at the center of the pipeline. With a reduction in the horizontal angle, the high-stress zone of the pipeline barely changes after the coal-seam mining is complete; however, the maximum equivalent stress increases. In the process of coal-seam mining, a lesser angle between the pipeline and the coal-seam mining strike corresponds to a faster increase in the maximum equivalent stress of the pipeline; the change in the equivalent stress of the pipeline increases with the mining length.
- A local high-stress zone gradually appears with an increase in the excavation length when the coal seam is mined longitudinally. The high-stress zone of the pipeline remains stable when the mining length is >200 m. When the mining length is 40 m, a small amount of stratum displacement occurs in a small range, which is mainly concentrated above the mining area and has no surface impact. Surface displacement gradually occurs, and the range of the stratum displacement gradually increases with an increasing mining length.
- The equivalent stress of the pipeline increases with an increase in the pipe–soil friction coefficient when the width of the goaf is constant. The effect of the pipe–soil friction coefficient on the equivalent stress of the pipeline is significantly apparent with a wider goaf.
- With an increase in the coal-seam dip angle, the von Mises stress decreases, and the position of the maximum stress towards the side of the coal-seam uphill. The maximum equivalent stress of the pipeline is 432 MPa when the inclination angle of the coal seam is 15° and the goaf width is 300 m. The pipeline reached failure under these working conditions. Therefore, to reduce the influence of coal mining on the gas pipeline above the goaf, the mining angle of the coal seam should be maximized.
- We suggest that the angle between the coal seam mining direction and the pipeline axial direction be 90° to reduce the influence of coal seam mining on the buried pipeline when it is horizontal. For the coal seam with a dip angle to the horizontal direction, we suggest that the mining direction and the horizontal direction be inclined to mining in order to reduce the influence of coal seam mining on the buried pipe.
- The pipeline is affected not only by internal pressure but also by internal fluid. We suggest to introduce the fluid-structure coupling model to study the mechanical behavior of the goaf pipeline in practical engineering.
Data Availability Statement
Conflicts of Interest
- Wang, T.; Wei, S.; Jiang, B.; Li, L. Effect of surface deformation of steeply inclined goaf on pipeline. Acta Geol. Sin. 2019, 93, 314–318. [Google Scholar]
- Xia, M.; Zhang, H.; Wang, B.; Gu, X. Strain analysis of buried pipelines in continuous mining subsidence areas based on shell element. Oil Gas Storage Transp. 2018, 37, 256–262. [Google Scholar]
- Karmis, M. Mining subsidence and its prediction in the Appalachian coalfield. Int. J. Rock Mech. Min. Sci. Geomech. Abstr. 1984, 21, 64. [Google Scholar]
- Peng, S.S.; Lou, Y. Determination of stress field in buried thin pipelines resulting from ground subsidence due to longwall mining. Min. Sci. Technol. 1988, 6, 205–216. [Google Scholar] [CrossRef]
- Xu, X.D.; He, K.; Su, Y. Safety analysis of pipe-soil coordination deformation affected by mining subsidence. Geotech. Geol. Eng. 2020, 38, 2187–2198. [Google Scholar] [CrossRef]
- Cao, Y.; Zhen, Y.; He, Y.; Zhang, S.; Sun, Y.; Yi, H.; Liu, F. Prediction of limit pressure in axial through-wall cracked X80 pipeline based on critical crack-tip opening angle. J. China Univ. Pet. 2017, 41, 139–146. [Google Scholar]
- Zhen, Y.; Tian, H.; Yi, H.; Cao, Y.; Zhang, S. Constraint-corrected fracture failure criterion based on CTOD/CTOA. Int. J. Fract. 2018, 214, 115–127. [Google Scholar] [CrossRef]
- Liu, X.; Zhang, H.; Han, Y.; Xia, M.; Zheng, W. A semi-empirical model for peak strain prediction of buried X80 steel pipelines under compression and bending at strike-slip fault crossings. J. Nat. Gas Sci. Eng. 2016, 32, 465–475. [Google Scholar] [CrossRef]
- Han, B.; Wang, Z.; Wu, Z.; Zhao, H.; Jing, H. Application of strain-based theory in failure analysis of pipeline subjected to mining collapse areas. J. China Univ. Pet. 2012, 36, 6. [Google Scholar]
- Iwanec, A.M.S.; Carter, J.P.; Hambleton, J.P. Geomechanics of subsidence above single and multi-seam coal mining. J. Rock Mech. Geotech. Eng. 2016, 8, 304–313. [Google Scholar] [CrossRef][Green Version]
- Wang, Z.; Song, G.; Ding, K.; Bellucci, S. Study on the Ground Movement in an Open-Pit Mine in the Case of Combined Surface and Underground Mining. Adv. Mater. Sci. Eng. 2020, 2020, 8728653. [Google Scholar] [CrossRef]
- Kalisz, P. Impact of Mining Subsidence on Natural Gas Pipeline Failures. IOP Conf. Ser. Mater. Sci. Eng. 2019, 471, 042024. [Google Scholar] [CrossRef]
- Wang, X.; Shuai, J.; Zhang, J. Mechanical response analysis of buried pipeline crossing mining subsidence area. Rock Soil Mech. 2011, 32, 3373–3378. [Google Scholar]
- Wang, H.; Zhao, X. Stress Deformation Analysis of Buried Pipeline under Mining Subsidence. Pipeline Tech. Equip. 2019, 6, 6. [Google Scholar] [CrossRef]
- Wang, X.; Zhou, X.; Li, S.; Zhang, N.; Ji, L.; Lu, H. Mechanism Study of Hydrocarbon Differential Distribution Controlled by the Activity of Growing Faults in Faulted Basins: Case Study of Paleogene in the Wang Guantun Area, Bohai Bay Basin, China. Lithosphere 2022, 2021, 7115985. [Google Scholar] [CrossRef]
- Zhang, J.; Liang, Z.; Han, C. Mechanical behaviour analysis of buried pressure pipeline crossing ground settlement zone. Int. J. Pavement Eng. 2015, 18, 608–621. [Google Scholar] [CrossRef]
- Zhang, P.; Hu, B.; Li, H.; Chen, X. Influence of different crossing angles on mechanical behavior of buried pipeline in goaf. J. Saf. Sci. Technol. 2020, 16, 82–88. [Google Scholar]
- Wu, K.; Zhang, H.; Liu, X.; Liu, J.; Fang, M.; Wang, B.; Zheng, W. Analysis on rationality of trench geometrical size for buried X80 natural gas pipeline under strike—Slip fault displacement. J. Saf. Sci. Technol. 2017, 13, 81–85. [Google Scholar]
- Cheng, X.; Huang, R.; Xu, L.; Ma, C.; Zhu, X. Parametric study on the trench designing for X80 buried steel pipeline crossing oblique-reverse fault. Soil Dyn. Earthq. Eng. 2021, 150, 106824. [Google Scholar] [CrossRef]
- Wang, X.; Hou, J.; Li, S.; Dou, L.; Song, S.; Kang, Q.; Wang, D. Insight into the nanoscale pore structure of organic-rich shales in the Bakken Formation, USA. J. Pet. Sci. Eng. 2019, 176, 312–320. [Google Scholar] [CrossRef]
- Wang, X.; Liu, Y.; Hou, J.; Li, S.; Kang, Q.; Sun, S.; Ji, L.; Sun, J.; Ma, R. The relationship between synsedimentary fault activity and reservoir quality—A case study of the Ek1 formation in the Wang Guantun area, China. Interpretation 2020, 8, sm15–sm24. [Google Scholar] [CrossRef]
- Kang, F.; Jie, P. Detailed Explanation of ABAQUS Geotechnical Engineering Examples; Posts & Telecom Press: Beijing, China, 2017. [Google Scholar]
- Liu, X.; Zhang, H.; Ndubuaku, O.; Xia, M.; Roger Cheng, J.J.; Li, Y.; Adeeb, S. Effects of stress–strain characteristics on local buckling of X80 pipe subjected to strike-slip fault movement. J. Press. Vessel. Technol. 2018, 140, 041408. [Google Scholar] [CrossRef]
- Yu, C.; Han, C.; Xie, R.; Wang, L. Mechanical behavior analysis of buried pipeline under stratum settlement caused by underground mining. Int. J. Press. Vessel. Pip. 2020, 188, 104212. [Google Scholar] [CrossRef]
- Zhang, J.; Liang, Z.; Han, C.J. Buckling behavior analysis of buried gas pipeline under strike-slip fault displacement. J. Nat. Gas Sci. Eng. 2014, 21, 921–928. [Google Scholar] [CrossRef]
- Wang, X. Research on Safety Assessment of Buried Pipeline in Typically Poor Geological Conditions. Diploma Thesis, China University of Petroleum (Beijing), Beijing, China, 2009; pp. 10–43. [Google Scholar]
- He, G. Mining Subsidence; China University of Mining and Technology Press: Xuzhou, China, 1991; pp. 116–148. [Google Scholar]
- Zhao, X. Stress and Deformation Analysis and Remote Monitoring of Buried Pipeline in Mined-Out Subsidence Area. Master’s Thesis, Southwest Petroleum University, Chengdu, China, 2015. [Google Scholar]
|Rock Classification||Density/kg·m−3||Elastic Modulus/MPa||Poisson’s Ratio||Cohesion/MPa||Friction Angle/°||Expansion Angle/°|
|Grid Size/m||Grid Number||Maximum Subsidence/m||Maximum von Mises Stress/MPa|
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Zhao, B.; Zhang, H.; Wang, Y.; Zhou, Y.; Zhang, J. Mechanical Behavior of Gas-Transmission Pipeline in a Goaf. Processes 2023, 11, 1022. https://doi.org/10.3390/pr11041022
Zhao B, Zhang H, Wang Y, Zhou Y, Zhang J. Mechanical Behavior of Gas-Transmission Pipeline in a Goaf. Processes. 2023; 11(4):1022. https://doi.org/10.3390/pr11041022Chicago/Turabian Style
Zhao, Bin, Hailun Zhang, Yu Wang, Yutong Zhou, and Jiaxin Zhang. 2023. "Mechanical Behavior of Gas-Transmission Pipeline in a Goaf" Processes 11, no. 4: 1022. https://doi.org/10.3390/pr11041022