Determination of slope debris flow mechanism in an open pit mine

Öz

On 17 November 2016, 16 workers lost their lives as a result of a landslide in an open pit copper mine in Madenköy district of Siirt province in southeastern Turkey. The main aims of this study is to investigate the causes of the accident, to reveal its mechanism and to be prepared for such mass movements that may occur in the future. The study area consists from the north and getting younger towards the south. Further investigations have shown that hydrogeological conditions and geological structure are the most important factors affecting the units. A large number of boreholes were drilled to reveal the 3D features of the area and cross sections were obtained. The most critical geotechnical numerical cross section that best represents the mass movements was selected and the stability of the area was analysed by finite element method in dry and water saturated conditions using Plaxis 2D and 3D Connect Edition v22 software.

Anahtar Kelimeler

• Open pit mine
• Mass Movement
• Debris Flow
• Finite Element Method
• Back Analysis

Bir açık ocak örneğinde yamaç molozu akma mekanizmasının belirlenmesi

Öz

17 Kasım 2016 tarihinde, Türkiye'nin güneydoğusundaki Siirt ilinin Madenköy ilçesinde bulunan bir açık ocak bakır madeninde meydana gelen heyelan sonucunda 16 işçi hayatını kaybetmiştir. Bu çalışmanın temel amacı, kazanın nedenlerini araştırmak, mekanizmasını ortaya koymak ve gelecekte meydana gelebilecek bu tür kütle hareketlerine karşı hazırlıklı olmaktır. Çalışma alanı Bitlis Masifi ile başlayan Eosen yaşlı birimler ile kuzeyden başlayıp güneye doğru gençleşen Paleozoik birimlerden oluşmaktadır. Daha sonraki incelemeler hidrojeolojik koşulların ve jeolojik yapının birimleri etkileyen en önemli faktörler olduğunu göstermiştir. Çalışma alanının jeolojik, jeoteknik ve hidrojeolojik özelliklerinin belirlenmesi amacıyla çok sayıda sondaj kuyusu açılarak alanın 3 boyutlu özellikleri ortaya çıkarılmış ve kesitler elde edilmiştir. Kütle hareketlerini en iyi temsil eden kritik jeoteknik sayısal kesit seçilmiş ve bölgenin duraylılığı Plaxis 2D ve 3D Connect Edition v22 yazılımı kullanılarak kuru ve suya doygun koşullarda sonlu elemanlar yöntemi ile analiz edilmiştir.

Anahtar Kelimeler

• Açık Ocak Madeni
• Kütle hareketi
• Moloz Akması
• Sonlu Elemanlar Yöntemi
• Geri Analiz

Kaynakça

1. M. Lashgari, C.A. Özturk, Slope failure and stability investigations for an open pit copper mine in Turkey, Environmental Earth Sciences, 81 (5), 1-17, 2022. https://doi.org/10.1007/s12665-021-10125-7.
2. M.A. Biot, “General Theory of Three-Dimensional Consolidation”, Journal of Applied Physics, 12, 155-164, 1941. https://doi.org/10 .1063/1.1712886.
3. S.M. Brooks, M.J. Crozier, T.W. Glade and M.G. Anderson, “Towards establishing climatic thresholds for slope instability: use of a physically-based combined soil hydrology-slope stability model”, Pure and Applied Geophysics, 161, 881-905, 2004. https://doi.org/10.1007/ s00024-003-2477-y.
4. P.L. Wilkinson, M.G. Anderson and D.M. Lloyd, An integrated hydrological model for rain-induced landslide prediction, Earth Surface Processes and Landforms, 27 (12), 1285-1297, 2002. https://doi.org /10.1002/esp.409.
5. S. Weill, E. Mouche, J. Patin, A generalized Richards equation for surface/subsurface flow modelling, Journal of Hydrology, 366 (1-4), 9-20, 2009. https://doi.org/10.1016/j.jhydrol.2008.12.007.
6. M. Karthikeyan, Unsaturated seepage and slope stability analysis, MSc Thesis, National University of Singapore, Singapore, 2000.
7. L. Cascini, S. Cuomo, M. Pastor and G. Sorbino, Modeling of rainfall induced shallow landslides of the flow-type, Journal of Geotechnical and Geoenvironmental Engineering, 136 (1), 85-98, 2010. https://doi.org/10.1061/(ASC)GT.1943-5606.0000182
8. M. Raj, A. Sengupta. Rain-triggered slope failure of the railway embankment at Malda, India Acta Geotechnica, 9 (5), 789-798, 2014. https://doi.org/ 10.1007/s11440-014-0345-9.

9. S.Y. Liu, L.T. Shao and H.J. Li, Slope stability analysis using the limit equilibrium method and two finite element methods, Computers and Geotechnics, 63, 291-298, 2015. https://doi.org/10.1016/j.compgeo. 2014.10.008.
10. W. Fellenius, Calculation of stability of earth dams, In: Transactions. 2nd International Congress On Large Dams, 4, pp. 445-9, 1936.
11. A.W. Bishop, The use of the slip circle in the stability of slopes, Geotechnique 5 (1), 7-17, 1955. https://doi.org/10.1680/geot.1955.5.1.7.
12. J. Lowe, L. Karafiath, Stability of Earth Dams Upon Drawdown, Proceedings of the 1st PanAm Conference on Soil Mechanic and Foundation Engineering, Mexico City, 2, pp. 537-552, 1960.
13. N.R. Morgenstern, V.E. Price, The analysis of the stability of general slip surfaces, Geotechnique, 15 (1), 79-93, 1965. https://doi.org/10.1680/geot.1965.15.1.79
14. E.E.A. Spencer, Method of the analysis of the stability of embankments assuming parallel interslice forces, Géotechnique, 1 (1), 11-26, 1967. https://doi.org/10 .1680/geot.1967.17.1.11.
15. N. Janbu, Slope stability computations, Soil Mechanics and Foundation Engineering Report, Technical University of Norway, Trondheim, 1968.
16. S.K. Sarma, Stability Analysis of Embankments and Slopes, Géotechnique, 23 (3), 423-433, 1973. https:// doi.org/ DOI: 10.1061/AJGEB6.0000903.
17. D.A. Bouzid, Finite element analysis of slope stability by expanding the mobilized principal stress Mohr's circles-Development, encoding and validation-, Journal of Rock Mechanics and Geotechnical Engineering, 14, (4), 1165-1179, 2022. https://doi.org/10.1016 /j.jrmge .2022.01.016.
18. A.M.C. Sengör, Y. Yılmaz, Tethyan evolution of Turkey: a plate tectonic approach, Tectonophysics, vol. 75, pp.181-241, 1981. https://doi.org/10.1016/0040-1951(81)90275-4.
19. E. Culfa, E. Genç, E. Yıldırım, Interpretation of Relationship between Field and Monitored Data in Madenköy (Siirt) Open-Pit Copper Mining, MSc Thesis, Istanbul Technical University, 2018.
20. F. Alyamaç, Siirt İli Madenköy, Hürmüz ve Soğanlı (Miskin) Köylerinin Jeolojik İncelenmesi, MTA Araştırma Raporu, 42 s., Ankara, 1979.
21. C. Baştuğ, Bitlis Napının Stratigrafisi ve Güneydoğu Anadolu Sütür Zonunun Evrimi, Yeryuvarı ve İnsan, 1, (3), 55-61, 1976.
22. A. Çağatay, Güneydoğu Anadolu Bakır Yataklarının Jeolojik - Mineralojik Araştırmaları, MTA Enstitüsü Yayınları, 89, pp. 46-69, Ankara, 1977.
23. M.A. Çağlayan, R.N. İnal, M. Şengün and A, Yurtsever, Structural setting of Bitlis massif. In O. Tekeli and M.C. Göncüoğlu (eds), International Symposium on the Geology of the Taurus Belt, Proceedings, pp. 245-254, Ankara, 1984.
24. R. Çalgın, Geology and Mineralogy of the Siirt -Madenköy Deposit, Turkey. Special Publication of thSociety for Geology Applied to Mineral Deposits, 1, pp.217, 1980.
25. M.C. Göncüoğlu, N. Turhan, Geology of the Bitlis Metamorphic Belt, In: O. Tekeli and M.C. Göncüoğlu (eds), International Symposium on the Geology of the Taurus Belt, Proceedings, pp.237-244, Ankara, 1984.
26. R. Yıldırım, F. Alyamaç, Siirt İli Madenköy Hürmüz Bölgesinin Jeolojik İncelenmesi, MTA Enstitüsü, Rapor No 1444, MTA İnceleme 5811, Ankara, 1976.
27. F. Kayhan, R. Yıldırım, Y. Ulutürk, Siirt Madenköy Copper Deposit SE-Turkey, XXVII. Geologorum Conventus, 11 (2), 223, 4-14 August, Moscow. 1984.
28. M, Şengün, Tatvan'ın güneyinin jeolojik/petrografik incelenmesi (Bitlis massif), PhD Thesis, Istanbul Technical University, 157p., Istanbul, 1984.
29. D.E. Karıg, H. Kozlu, Late Palaeogene-Neogene evolution of the triple junction region near Maras south-central Turkey. Journal of the Geological Society, London, 147 (1990), 1023-1034, 1990. https://doi.org/10.1144/gsjgs.147.6.1023.
30. Y. Ulutürk, Siirt Madenköy Bakır Yatağı - İnceleme, MTA Enstitüsü, Ankara, 1999.
31. M.N. Çağlayan, M. Şengün, 1:100.000 Geniş Ölçekli Türkiye Jeolojik Haritaları (pafta Van-L48), MTA Genel Müdürlüğü, Jeolojik Etüt Dairesi Başkanlığı Yayını no. 66, Ankara, 2002.
32. T. Öztaş, V. Yavuz and M. Korkut, Siirt ili-Şirvan ilçesi-Madenköy Park Elektrik Üretim Madencilik San. ve Tic. A.Ş. Bakır Madeni Açık İşletme Alanının 3B Hidrojeolojik Modeli ve Nihai Susuzlaştırma Projesi, Final Raporu, Istanbul, Türkiye, 2016.
33. Hexacon, Geosystems Division, Italy, Interferometric Radar, Ibis FM-Evo https://idsgeoradar.com/products/ interferometric-radar/ibis-fm-evo, Accessed 3 January 2023.
34. T. Carlà, P. Farina, E. Intrieri, H. Ketizmen and N. Casagli, Integration of ground-based radar and satellite InSAR data for the analysis of an unexpected slope failure in an open-pit mine, Engineering Geology vol. 235, pp. 39-52, 2018. https://doi.org/10.1016/j .enggeo .2018.01.021.
35. E. Intrieri, T. Carlà and G. Gigli, Forecasting the time of failure of landslides at slope-scale. Earth-Science Reviews, vol. 1, no.193, pp. 333-349, 2019. https:// doi.org/10.1016/j.earscirev.2019.03.019.
36. H. Çetinkaya, A. Usta, Siirt-Madenkoy IBIS-M Uygulama Raporu, Ankara, (2015-16).
37. O.C. Zienkiewicz, C. Humpheson and R.W. Lewis, Associated and non-associated visco-plasticity and plasticity in soil mechanics, Géotechnique, vol. 25, no.4, pp.671-689, 1975. https://doi.org/10.1680/geot .1975.25.4.67.
38. D.J. Naylor, Finite Elements and Slope Stability, In: J.B. Martins (eds) Numerical Methods in Geomechanics. NATO Advanced Study Institutes Series, vol 92. Springer, Dordrecht, 1982. https://doi.org/10.1007/978-94-009-7895-9_10.
39. I.B. Donald, S.K. Giam, Application of the nodal displacement method to slope stability analysis, Proceedings of the 5th Australia-New Zealand Conference on Geomechanics, 22-26 August, Sydney, Australia, pp.456-460, 1988.
40. T, Matusi, K.C. San, Finite element slope stability analysis by shear strength reduction technique, Soils and Foundations, vol. 32, no.1, pp. 59-70, 1992. https://doi.org/10.3208/sandf1972.32.59.
41. K. Ugai, D. Leshchinsky, Three-dimensional limit equilibrium and finite element analyses: a comparison of results, Soils and Foundations, vol. 35, no.4, pp. 1-7, 1995. https://doi.org/10 .3208/sandf.35.4_1.
42. E.M. Dawson, W.H. Roth and A. Drescher, Slope stability analysis by strength reduction, Géotechnique vol. 49, no. 6, pp. 835-840, 1999. https://doi.org/10 .1680 /geot.1999.49.6.835.
43. D.V. Griffiths, P.A. Lane, Slope Stability Analysis by Finite Elements, Geotechnique, vol. 49, no. 3, pp. 387-403, 1999. https://doi.org/10.1680/geot.1999.49.3 .387.
44. Y.M. Cheng, T. Lansivaara and W.B. Wei, Two-dimensional slope stability analysis by limit equilibrium and strength reduction methods. Computers and Geotechnics, vol. 34, no. 3, pp. 137-150, 2007. https://doi.org/10.1016/j.compgeo.2006.10 .011.
45. R. Dey, S. Javankhoshdel, 3D FEM modeling of the initiation of progressive landslides, Proceedings of 74th Canadian Geotechnical Conference and 14th Joint CGS/IAH-CNC Groundwater Conference (GeoNiagara 2021), September 26-29, Toronto, Niagara, Canada, 2021. https://doi.org/10.1201/ 9781003188339.
46. E.N. Bromhead, M. L. Ibsen, X. Papanastassiou and A.A. Zemichael, Three-dimensional stability analysis of a coastal landslide at Hanover Point, Isle of Wight, Quarterly Journal of Engineering Geology and Hydrogeology, 35, 79-88, 2002. https://doi.org/10 .1144/qjegh.35.1 .79.
47. N. Janbu, Slope stability computations, In: Hirschfeld RC, Poulos SJ (eds) Embankment- Dam Engineering: Cassagrande Volume. John Wiley & Sons Inc, NewYork, 47-86, 1973. https://doi.org/10.1016/0148-9062(75)90139-4.