STABILITY ANALYSIS OF STONE COLUMN SLOPES UNDER DIFFERENT EARTHQUAKE LOADS

Abstract

How a slope behaves under the action of a dynamic load such as an earthquake is of great importance in stability analyses of slopes. Improving the region where slope failure occurs or preventing potential slope failure can lead to reducing the factors that excite movement in a slope and/or increasing the sliding resistance of the soils. In this study, the stone column method was used as an improvement technique. In the analysis performed with Plaxis 2D, safety factors were defined for slopes with different slope angles, soil cohesion, and three different earthquake magnitudes. Later, the slopes with the same characteristics were improved using the stone column method. The slopes were improved with different s/D ratios and different internal friction angles of the stone column. The same earthquake forces were also applied to the improved slopes and the factors of safety were determined.

In the study, slope models with stone columns designed without the effect of earthquake force showed an increase in safety values in the range of 1.01to 1.34 times compared to slope models without stone columns. It was found that the safety values of the slope models with stone columns increased by 1.02-1.80 times compared to the slope models without stone columns under the effect of earthquake force

Keywords

• Acceleration
• Earthquake forces
• Slope stability
• Stone columns
• Finite Element Analysis

Farklı Deprem Kuvvetleri Altında Taş Kolonlu Şevlerin Stabilite Analizi

Abstract

Bir şevin deprem gibi dinamik bir yükün etkisi altında nasıl tepki verdiği, şevlerin duraylılık analizlerinde çok önemlidir. Bir şev göçmenin meydana geldiği bölgeyi iyileştirmek veya olası bir şev göçmesini önlemek, bir şevde hareketi teşvik eden faktörlerin azalmasına ve/veya zeminlerin kayma direncinin artmasına sağlar. Bu çalışmada iyileştirme tekniği olarak Taş Kolon yöntemi kullanılmıştır. Plaxis 2D ile yapılan analizde, farklı şev açıları, zemin kohezyonu ve üç farklı deprem kuvveti ile modellenen şevlerin güvenlik faktörleri belirlenmiştir. Daha sonra aynı özelliklere sahip şevler taş kolon yöntemi ile iyileştirilmiştir. Eğimler, farklı s/D oranları ve farklı taş kolon iç sürtünme açıları kullanılarak iyileştirilmiştir. Aynı deprem kuvvetleri iyileştirilmiş şevlere de uygulanmış ve güvenlik faktörleri bulunmuştur.
Çalışmada, deprem kuvvetinin etkisi olmadan tasarlanan taş kolonlu şev modelleri, taş kolonsuz şev modellerine göre güvenlik değerlerinde 1.01-1.34 kat arasında bir artış göstermiştir. Taş kolonlu şev modellerinin güvenlik değerlerinin, deprem kuvvetinin etkisi altında taş kolonsuz şev modellerine göre 1,02-1,80 arttığı görülmüştür.

Keywords

• İvme
• Deprem kuvvetleri
• Şev stabilitesi
• Taş kolonlar
• Sonlu Elemanlar Analizi

References

1. 1. Abramson, L.W. (1996) Slope Stability and Stabilization methods. John Wiley&Sons, Inc., New York.
2. 2. Afad (2011) Van earthquake (23 October 2011) report, T.R. Prime Ministry Disaster and Emergency Management Presidency, Earthquake Department.
3. 3. Ansal, A. M. & Erken, A. (1986) Behavior of cohesive soils under repeated stresses, Earthquake Research Bulletin, 50, 10-53 (In Turkish).
4. 4. Azzam, W.R. (2014). Finite Element Analysis of Skirted Foundation Adjacent to Sand Slope under Earthquake Loading, Housing and Building National Research Center Journal, 2014-1, 1-9. https://doi.org/10.1016/j.hbrcj.2014.04.001
5. 5. Baez, J.I. and Martin, G.R. (1995) Permeability and Shear Wave Veloci Ty of Vibro Replacement Stone Columns, Soil Improvement for Earthquake Hazard Mitigation ASCE Geotechnical Special Publication, 49, 66-81.
6. 6. Bray. J.D. and Travasarou, T. (2011) Pseudostatic slope stability procedure, 5th international conference on earthquake geotechnical engineering, Santiago, Chile.
7. 7. Bromhead, E. N. (1986) The Stability of Slope, Surrey Universitypress. USA.
8. 8. Çadır, C.C., Vekli, M. & Şahinkaya, F. (2021). Numerical analysis of a finite slope improved with stone columns under the effect of earthquake force, Nat Hazards, 106(1), 173-211. doi:10.1007/s11069-020- 04456-0.

9. 9. Chatterjee K, Choudhury D (2012) Seismic stability analyses of soil slopes using analytical and numeriial approaches, Paper presented at Iset Golden Jubilee Symposium, Indian Society of Earthquake Technology Department of Earthquake Engineering Building, Paper No. C005 pp 20–21.
10. 10. Conno, S.S. and Gorski. A.G. (2000) Timely solution for the Nojoqi grade Landslide repair, US 101 South of Buellton. Paper presented at 51st annual highway geology symposium, Seattle, 1–11.
11. 11. Deb, K., Basudhar, P.K., and Chandra, S. (2008) Response of Multilayer Geosynthetic- Reinforced Bed Resting on Soft Soil with Stone Columns, Computers and Geotechnics, 35, 323–330. doi:10.1016/j.compgeo.2007.08.004
12. 12. Fathi, E., and Mohtasham, R. (2016) Numerical Analysis of the Reinforced Stone Column by Geosynthetic on Stability of Embankment, Proceedings of the World Congress on Civil, Structural, and Environmental Engineering (CSEE’16), Prague, Czech Republic.
13. 13. Ghosh S (2014) Pseudo-static analysis of slope considering circular rupture surface, Int J Geotech Earthq Eng, 5(2):37–43. doi:10.4018/ijgee.2014070103.
14. 14. Griffiths D. V. and Lane P. A. (2015) Slope stability analysis by finite elements, Geotechnique, 49(3), 387-403. doi:10.1680/geot.1999.49.3.387
15. 15. Hack, R., Alkema, D., Kruse, G.A.M., Leenders, N. and Luzi, L. (2007) Influence of earthquakes on the stability of slopes, Engineering Geology, 91, 4-15. doi:10.1016/j.enggeo.2006.12.016
16. 16. Hasheminezhad, A. and Hadi. B. (2019) Seismic Response of Shallow Foundations over Liquefiable Soils Improved by Deep Soil Mixing Columns, Computers and Geotechnics, 110, 251-273. doi:10.1016/j.compgeo.2019.02.019
17. 17. Karikari Y.O and Agyei Y.G (2000) Stability of slopes over colluvium: investigation, analysis and stabilization. Inproceedings. Conference on Geotechnical Engineering, 19- 24 November, Melbourne, Australia.
18. 18. Karray M, Hussien MN, Ghobrial F (2017) Incorporation of the spectral pseudo-static procedure into the limit equilibrium slope stability software –SVSLOPE. Paper presented at Canadien Geotechnical Conference.
19. 19. Kim, J. M., Son W.D., Mahmood, K., & Ryu, J. H. (2012). Site response and shear behavior of stone column-improved ground under seismic loading. 15 WCEE, Lisboa, 1–8.
20. 20. Kirsch, F. and Sondermann, W. (2003) Field measurements and numerical analysis of the stress distribution below stone column supported embankments and their stability, Paper presente at international workshop on geotechnics of soft soil theory and practice, Essen, 595–600.
21. 21. Kohgo, Y. and Yamashita, T. (1998) Finite element analysis of fill type dams-stability during construction by using the effective stress concept. Proc. Conf. Numerical Method in Geomech., 111(2), 238-250.
22. 22. Kontoe, S., Pelecanos, L. and Potts, D. (2013) An important pitfall of pseudo-static finite element analysis, Comput Geotech, 48:41–50. doi:10.1016/j.compgeo.2012.09.003.
23. 23. Kumar, K. (2008) Basic Geotechnical Earthquake Engineering, New Age International (P) Limited Publishers, New Delhi
24. 24. Malhotra, S. and Lee, T.S. (2008) Reinforcement of Slopes for Seismic Stability, International Conference on Case Histories in Geotechnical Engineering, 1-11.
25. 25. Melo, C. and Sharma, S. (2014) Seismic coefcients for pseudostatic slope analysis, Paper presented at 13th world conference on earthquake engineering Vancouver, B.C., Canada.
26. 26. Nadı, B, Askarı, F. and Farzaneh, O. (2014) Seismic performance of slopes in pseudo-static designs with diferent safety factors, IJST Transact Civil Eng, 38(C2),465–483.
27. 27. Ogawa. S., Shibayama, T. and Yamagucjı, H. (1977). Dynamic strength of saturated cohesive soil. Proc.7th Int. Soil Mech.& Found. Eng., 2, 103-107.
28. 28. Özay, R. and Erken, A. (2003) Behavior of low plasticized clayey soils under repeated loading, 5th National Earthquake Engineering Conference, Istanbul. (In Turkish).
29. 29. Plaxis 2D Fiite Elemet Program (1987). Plaxis 2D, https://www.plaxis.com/product/plaxis-2d/ (Sep. 29, 2020).
30. 30. Plomteux, C., Porbaha, A. and Spaulding, C. (2004) CMC foundation system for embankment support a case history, Proceedings of geo support conference Orlando, Florida, USA, 980–992
31. 31. Presti, D.L., Marchetti, D. and Fontana, T. (2014) Pseudo-static vs. pseudo-dynamic slope stability analysis in seismic areas of the northern Apennines (Italy), Rivista Italiana Di Geotecnica, 4:13–29.
32. 32. Qin, C.B. and Chian, S.C. (2018) New perspective on seismic slope stability analysis, Int J Geomech, 18,7. doi:10.1061/(ASCE)GM.1943-5622.0001170
33. 33. Ryu, J.H. and Jim, M.K. (2013) Seismic Performance of Stone-Column- Reinforced Marine Soft Soil, EJGE, 18,497-508.
34. 34. Şahinkaya, F., Vekli, M., and Cadir, C.C. (2017). Numerical analysis under seismic loads of soils improvement with floating stone columns, Natural Hazards, 88(2) 891–917. doi:10.1007/s11069-017-2897-0
35. 35. Seed, H.B., and Chan, C.K. (1966) Clay Strength under Earthquake Loading Conditions, Proc. Amer. Soc. Civil Eng, 92, SM2, 53-78.
36. 36. Terzaghi, K. (1950) Mechanics of landslides (Berkey volume). Geological Society of America, New York, 83–124.
37. 37. Theirs, R.G., and Seed, H.B. (1969) Strength and Stress-Strain Characteristics of Clays Subjected to Seismic Loading Conditions, Vibration Effects of Earthquakes on Soils and Foundations, ASTM STP 450.
38. 38. White, D.J., Wissmann, K.J., Barnes, A.G., and Gaul, A.J. (2002) Embankment support :a comprasion of stone column and rammed aggregaten pier soil reinforcement, Transportation Researh Board, 81st Annual Meeting, Washington D.C
39. 39. Yang, C.W., Zhang, J.J, Fu, X. and Zhu, C.B. (2014) Improvement of pseudo-static method for slope stability analysis, J Mt Sci, 11(3),625–633. doi:10.1007/s11629-013-2756-8
40. 40. Zhang, Z., Han, J. and Ye, G. (2014) Numerical investigation on factors for deep-seated slope stability of stone column-supported embankments over soft clay, Eng Geol,168,104–113. doi:10.1016/j.enggeo.2013.11.004