Abstract
Coal and lignite (brown coal) are geo-resources that govern energy production for decades. Geomechanical challenges, particularly slope stability, related to surface coal and lignite mines are critical during operation and determine the post-coal era. Several failure incidents have been reported in mining areas, typically associated with a sub-horizontal failure surface on a weak—clay or marl—layer or an interface of low strength. This weak zone controls the soil profile in terms of stability and is common in several mines globally. In this work, the finite element method with the shear strength reduction technique is primarily employed to evaluate the slope stability of this profile. Three geotechnical software are initially compared, and results are identified as practically identical. Moreover, slopes with benches, as typically in mines, and without benches, as typically in slope stability analysis, are compared, with the no-benches analysis being consistently more conservative. The crucial parameters' effect is then examined: the height and the inclination of the slope, the inclination, thickness, and strength of the weak zone, and the strength of the overburden soil. Their effect on slope stability is quantified by combining the probabilistic point estimate method with the finite element method. It is concluded that the inclination and strength of the weak zone and the water conditions are the most critical parameters and control the stability. This work can support a preliminary slope stability analysis and expands the knowledge and understanding of slope stability of a weak zone profile.
Article Highlights
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Slope stability is performed on a soil profile with a weak zone, describing a common type of coal mines' failure in several countries.
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Numerical issues of practical importance are addressed for the simulation and analysis of the problem.
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The inclination and shear strength of the weak zone together with the water conditions control the stability of the mines' slopes.
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Baecher GB, Christian JT (2003) Reliability and statistics in geotechnical engineering. Wiley, UK
Bednarczyk Z (2017) Landslide monitoring and counteraction technologies in polish lignite opencast mines. Workshop on world landslide forum. Springer, Berlin, pp 33–43. https://doi.org/10.1007/978-3-319-53483-1_6
Bishop AW, Morgenstern N (1960) Stability coefficients for earth slopes. Géotechnique 10:129–153. https://doi.org/10.1680/geot.1960.10.4.129
BP (2020) BP Statistical Review of World Energy June 2020
Bromhead E (1992) The stability of slopes. CRC Press. https://doi.org/10.4324/9780203975350
Cała M, Cyran K, Jakóbczyk J, Kowalski M (2020) The Challenges of Open-Pit Mining in the Vicinity of the Salt Dome (Bełchatów Lignite Deposit, Poland). Energies 13:1913. https://doi.org/10.3390/en13081913
Carranza-Torres C, Fosnacht D, Hudak G (2017) Geomechanical analysis of the stability conditions of shallow cavities for compressed air energy storage (CAES) applications. Geomech Geophys Geo-Energy Geo-Resour 3:131–174. https://doi.org/10.1007/s40948-017-0049-3
Ghadrdan M, Shaghaghi T, Tolooiyan A (2020) Sensitivity of the stability assessment of a deep excavation to the material characterisations and analysis methods. Geomech Geophys Geo-Energy Geo-Resour 6:59. https://doi.org/10.1007/s40948-020-00186-6
Ghadrdan M, Dyson AP, Shaghaghi T, Tolooiyan A (2021) Slope stability analysis using deterministic and probabilistic approaches for poorly defined stratigraphies. Geomech Geophys Geo-Energy Geo-Resour 7:1–17. https://doi.org/10.1007/s40948-020-00189-3
Griffiths D, Fenton GA (2004) Probabilistic slope stability analysis by finite elements. J Geotech Geoenviron Eng 130:507–518. https://doi.org/10.1061/(asce)1090-0241(2004)130:5(507)
Huang YH (1983) Stability analysis of earth slopes. Van Nostrand Reinhold Company Inc New York. https://doi.org/10.1007/978-1-4684-6602-7
Kavvadas M, Agioutantis Z, Schilizzi P, Steiakakis C (2013) Stability and movements of open-pit lignite mines in Northern Greece. In: Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, pp 2193–2196
Kavvadas M, Roumpos C, Schilizzi P (2020) Stability of deep excavation slopes in continuous surface lignite mining systems. Geotech Geol Eng 38:791–812. https://doi.org/10.1007/s10706-019-01066-x
Khandelwal M, Rai R, Shrivastva B (2015) Evaluation of dump slope stability of a coal mine using artificial neural network. Geomech Geophys Geo-Energy Geo-Resour 1:69–77. https://doi.org/10.1007/s40948-015-0009-8
L’Heureux J-S et al (2012) Identification of weak layers and their role for the stability of slopes at Finneidfjord, northern Norway. In: Yamada Y, Kawamura K, Ikehara K, Ogawa Y, Urgeles R, Mosher D, Chaytor J, Strasser M (eds) Submarine mass movements and their consequences. Springer, pp 321–330. https://doi.org/10.1007/978-94-007-2162-3_29
Lastras G, Canals M, Urgeles R, Hughes-Clarke JE, Acosta J (2004) Shallow slides and pockmark swarms in the Eivissa Channel. Western Mediterr Sea Sedimentol 51:837–850. https://doi.org/10.1111/j.1365-3091.2004.00654.x
Leonardos M (2004) Methods and procedures of monitoring, assessment and improvement of the excavated slopes stability in the deep Greek lignite exploitations. PhD Dissertation (in Greek). National Technical University of Athens, Greece
Liu SY, Shao LT, Li HJ (2015) Slope stability analysis using the limit equilibrium method and two finite element methods. Comput Geotech 63:291–298. https://doi.org/10.1016/j.compgeo.2014.10.008
McQuillan A, Canbulat I, Payne D, Oh J (2018) New risk assessment methodology for coal mine excavated slopes . Int J Min Sci Technol 28:583–592. https://doi.org/10.1016/j.ijmst.2018.07.001
Mencl V (1977) Modern methods used in the study of mass movements bulletin of the international association of engineering geology. Bulle L’association Int De Géologie De L’ingénieur 16:185–197. https://doi.org/10.1007/bf02591480
Ozbay A, Cabalar AF (2015) FEM and LEM stability analyses of the fatal landslides at Çöllolar open-cast lignite mine in Elbistan. Turkey Landslides 12:155–163. https://doi.org/10.1007/s10346-014-0537-2
Plaxis (2020) Plaxis2D Connect Edition V20- 2D finite element geotechnical analysis software. Delft, Netherlands
Prountzopoulos G, Fortsakis P, Marinos V, Marinos P (2017) A large scale landslide in a coal mine in marly formations: Evaluation, analysis and rehabilitation. ISSMGE Int J Geoeng Case Hist 4:29–45. https://doi.org/10.4417/IJGCH-04-01-03
Puzrin AM, Gray TE, Hill AJ (2017) Retrogressive shear band propagation and spreading failure criteria for submarine landslides. Géotechnique 67:95–105. https://doi.org/10.1680/jgeot.15.p.078
Quinn P (2009) Large Landslides in Sensitive Clay in Eastern Canada and the Associated Hazard and Risk to Linear Infrastructure. PhD Dissertation. Queen's University, Canada
Rahardjo H, Ong TH, Rezaur RB, Leong EC (2007) Factors controlling instability of homogeneous soil slopes under rainfall. J Geotech Geoenviron Eng 133:1532–1543. https://doi.org/10.1061/(ASCE)1090-0241(2007)133:12(1532)
Rocscience (2019) Slide2 Version 7.0 - 2D limit equilibrium slope stability analysis. Toronto, Ontario, Canada
Rocscience (2020) RS2 Version 11.0 - Finite element analysis for excavations and slopes. Toronto, Ontario, Canada
Rosenblueth E (1975) Point estimates for probability moments. Proc Natl Acad Sci 72:3812–3814. https://doi.org/10.1073/pnas.72.10.3812
Solak KC, Tuncay E, Ulusay R (2017) An investigation on the mechanisms of instabilities and safe design of the south slope at a lignite pit (SW Turkey) based on a sensitivity approach. Bull Eng Geol Environ 76:1321–1341. https://doi.org/10.1007/s10064-017-1025-4
Steiakakis C, Apostolou E, Papavgeri G (2018) Large moving landslide inside a lignite mine in northern Greece. In: Aversa S, Cascini L, Picarelli L, Scavia C (eds) Landslides and engineered slopes experience theory and practice. CRC Press, pp 1867–1874
Theocharis AΙ, Zevgolis IE, Koukouzas NC (2021) Α comprehensive geotechnical characterization of overburden material from lignite mine excavations. Geomech Geophys Geo-Energy Geo-Resour 7:30. https://doi.org/10.1007/s40948-021-00230-z
Tschuchnigg F, Schweiger HF, Sloan SW (2015a) Slope stability analysis by means of finite element limit analysis and finite element strength reduction techniques part I: numerical studies considering non-associated plasticity. Comput Geotech 70:169–177. https://doi.org/10.1016/j.compgeo.2015.06.018
Tschuchnigg F, Schweiger HF, Sloan SW, Lyamin AV, Raissakis I (2015b) Comparison of finite-element limit analysis and strength reduction techniques. Géotechnique 65:249–257. https://doi.org/10.1680/geot.14.p.022
Tutluoglu L, Öge IF, Karpuz C (2011) Two and three dimensional analysis of a slope failure in a lignite mine. Comput Geosci 37:232–240. https://doi.org/10.1016/j.cageo.2010.09.004
Ulusay R, Gökçeoğlu C, Sönmez H, Tuncay E (2001) Causes, mechanism and environmental impacts of instabilities at Himmetoğlu coal mine and possible remedial measures. Environ Geol 40:769–786
Ulusay R, Ekmekci M, Tuncay E, Hasancebi N (2014) Improvement of slope stability based on integrated geotechnical evaluations and hydrogeological conceptualisation at a lignite open pit. Eng Geol 181:261–280. https://doi.org/10.1016/j.enggeo.2014.08.005
Ural S, Yuksel F (2004) Geotechnical characterization of lignite-bearing horizons in the Afsin-Elbistan lignite basin. SE Turkey Eng Geol 75:129–146. https://doi.org/10.1016/j.enggeo.2004.05.005
Urciuoli G, Picarelli L, Leroueil S (2007) Local soil failure before general slope failure. Geotech Geol Eng 25:103–122. https://doi.org/10.1007/s10706-006-0009-0
Verma D, Kainthola A, Thareja R, Singh T (2013) Stability analysis of an open cut slope in Wardha valley coal field. J Geol Soc India 81:804–812. https://doi.org/10.12691/ajmm-1-1-1
Wang S, Ahmed Z, Hashmi MZ, Pengyu W (2019) Cliff face rock slope stability analysis based on unmanned arial vehicle (UAV) photogrammetry. Geomech Geophy Geo-Energy Geo-Resour 5:333–344
Whitman RV (1984) Evaluating calculated risk in geotechnical engineering. J Geotech Eng 110:143–188. https://doi.org/10.1061/(ASCE)0733-9410(1984)110:2(143)
Zevgolis IE, Deliveris AV, Koukouzas NC (2018) Probabilistic design optimization and simplified geotechnical risk analysis for large open pit excavations. Comput Geotech 103:153–164. https://doi.org/10.1016/j.compgeo.2018.07.024
Zevgolis IE, Deliveris AV, Koukouzas NC (2019) Slope failure incidents and other stability concerns in surface lignite mines in Greece. J Sustain Mining 18:182–197. https://doi.org/10.1016/j.jsm.2019.07.001
Zevgolis IE, Theocharis AI, Deliveris AV, Koukouzas NC, Roumpos C, Marshall AM (2021) Geotechnical characterization of fine-grained spoil material from surface coal mines. J Geotech Geoenviron Eng 147:04021050. https://doi.org/10.1061/(asce)gt.1943-5606.0002550
Zhang W, Wang D (2020) Stability analysis of cut slope with shear band propagation along a weak layer. Comput Geotech 125:103676. https://doi.org/10.1016/j.compgeo.2020.103676
Zhigang T, Chun Z, Manchao H, Kuiming L (2020) Research on the safe mining depth of anti-dip bedding slope in Changshanhao Mine. Geomech Geophys Geo-Energy Geo-Resour 6:1–20. https://doi.org/10.1007/s40948-020-00159-9
Acknowledgements
This work has received funding from the European Union's Research Fund for Coal and Steel under the project "RAFF—Risk assessment of final pits during flooding slopes" grant agreement No 847299. Financial assistance by the European Commission is much appreciated.
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Mikroutsikos, A., Theocharis, A.I., Koukouzas, N.C. et al. Slope stability of deep surface coal mines in the presence of a weak zone. Geomech. Geophys. Geo-energ. Geo-resour. 7, 66 (2021). https://doi.org/10.1007/s40948-021-00265-2
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DOI: https://doi.org/10.1007/s40948-021-00265-2