Indian Geotechnical Journal

, Volume 49, Issue 6, pp 620–634 | Cite as

Stability Analysis of Colombo–Katunayake Expressway (CKE) Using Finite Element and Limit Equilibrium Methods

  • M. C. M. NasviEmail author
  • S. Krishnya
Original Paper


Colombo–Katunayake Expressway (CKE) is the second major highway in Sri Lanka connecting the International Airport at Katunayake to Colombo, and this expressway is constructed over soft soils, predominantly peat. A research study was conducted to analyse the stability of two critical sections of the CKE project using finite element method (FEM), limit equilibrium method (LEM) and Matsuo chart. In the FEM, PLAXIS 2D package was used to simulate the behaviour by using four different types of analyses: (1) Mohr–Coulomb (MC) analysis: MC model for all soil layers; (2) MC-SS 1 analysis: soft soil (SS) model for peat and MC model for remaining soil layers; (3) MC-SS 2 analysis: SS model for peat and soft clay layers and MC model for remaining soil layers; and (4) MC-SS-SSC analysis: soft soil creep (SSC) model for peat, SS model for soft clay and MC model for remaining soil layers. Further, LEM analysis was carried out using SLOPE/W and obtained factor of safety (FOS) values were compared with the FEM analysis. In addition, effect of geotextile on the long-term stability was analysed in FEM. Based on the outcome of the FEM analysis, it was noticed that MC-SS 2 model is the best model to predict the actual field condition for soft soil with high overconsolidation ratio values. In addition, FOS values obtained from PLAXIS were in very good agreement with those obtained from SLOPE/W. Incorporation of geotextile improves the stability of the embankment, and the optimum stiffness of the geotextile should be selected for practical applications.


Finite element method Limit equilibrium method Matsuo chart Peat Slope stability 



Bishop simplified method


Colombo–Katunayake Expressway




Compression index


Swelling index


Coefficient of secondary consolidation


Vertical settlement at the centre of the embankment


Modulus of elasticity of the soil


Initial void ratio


Janbu simplified method


Permeability of the soil




Morgenstern–Price method


Overconsolidation ratio


Ordinary method


Applied load in jth stage


Failure load


Soft soil


Soft soil creep


Shear strength reduction


Internal friction angle


Lateral displacement at the toe of the embankment


Saturated unit weight


Poisson’s ratio of the soil



  1. 1.
    Neher HP, Wehnrt M, Bonnier PG (2001) An evaluation of soft soil models based on the trial embankments. In: Proceedings of the 10th international conference on computer methods and advances in geomechanics, Tucson, Arizona, USAGoogle Scholar
  2. 2.
    Brinkgreve RBJ, Broere W, Watterman D (2006) Material model manual. PLAXIS-2D Version 8, Delft, The NetherlandsGoogle Scholar
  3. 3.
    Gunduz B (2010).Analysis of settlements of test embankments during 50 years—a comparison between field measurements and numerical analysis. Master’s Dissertation, LUND UniversityGoogle Scholar
  4. 4.
    Gustafsson P, Tian T (2011) Numerical study of different creep models used for soft soils, Master of Science thesis, CHALMERS University of TechnologyGoogle Scholar
  5. 5.
    Karunawardena WA, Oka F, Kimoto S (2007) Prediction of consolidation behavior of Sri Lankan peaty clay using an elasto-viscoplastic theory. Thesis report, University of KYOTOGoogle Scholar
  6. 6.
    Vipulanandan C, Bilgin PEO, Guezo PEY, Kalaiarasi P, BahadirErten M (2008) Prediction of embankment settlement over soft soils. Thesis, Report No: CIGNAT/UH 2009-6-1, University of HoustonGoogle Scholar
  7. 7.
    Premalal RPDS, Jayasinghe TWASL, Thilakasiri HS, Indrachapa KRTH (2013). Use of the observational approach for embankment construction on organic soil deposits in Sri Lanka. In: Proceeding of the 2nd international conference on sustainable built environments. Kandy, Sri LankaGoogle Scholar
  8. 8.
    Zhang Q, Qin X, Dong Z, Yan X (2011) Foundation treatments for embankments over highly compressible peat in CKE project. J Civ Eng Archit 5(12):1138–1141Google Scholar
  9. 9.
    Matsuo M, Kawamura K (1977) Diagram for construction control of embankment on soft soil. Jpn Soc Soil Mech Found Eng 17(03):37–52CrossRefGoogle Scholar
  10. 10.
    Cala M, Flisiak J (2003) Slope stability analysis with FLAC and limit equilibrium methods. In: Proceeding of the 15th international conference on computer methods in mechanics, Gliwice, PolandGoogle Scholar
  11. 11.
    Chai IC, Bergado DT (1993) Some techniques for finite element analysis of embankments on soft ground. Can Geotech J 30(4):710–719CrossRefGoogle Scholar
  12. 12.
    Aziz AHBA (2010) Stability and deformation analysis of embankments. Undergraduate thesis, University of Teknologi, MalaysiaGoogle Scholar
  13. 13.
    Matsui T, San K (1992) Finite element slope stability analysis by shear strength reduction technique. Soil Found 32:59–70CrossRefGoogle Scholar
  14. 14.
    Jaritngam S, Chuchom S, Limsakul C, Jaritngam R (2001) Slope stability analysis using neural network. In: The 6th mining, metallurgical and petroleum engineering conference on resources exploration and utilization for sustainable environment (REUSE), pp 6–24Google Scholar
  15. 15.
    Jitno H, Gofar N (2005) Stability and deformation analysis of failed embankments founded on soft clays. Malays J Civ Eng 17(1):1–12CrossRefGoogle Scholar
  16. 16.
    Aryal KP (2006) Slope stability evaluations by limit equilibrium and finite element methods. Doctoral thesis, NTNU OpenGoogle Scholar
  17. 17.
    Hammouri NA, Adballah I, Malkawi H, Yamin MAM (2008) Stability analysis of slope using finite element method and limited equilibrium method. Bull Eng Geol Environ 67:471–478CrossRefGoogle Scholar
  18. 18.
    Chai JC, Miura N, Shen SL (2002) Performance of embankments with and without reinforcement on soft subsoil. Can Geotech J 39(4):838–848CrossRefGoogle Scholar
  19. 19.
    Hsi J, Gunasekara C, Nguyen V (2005) Characteristics of soft peats, organic soils and clays, Colombo-Katunayake Expressway, Sri Lanka. Elsevier Geo-Eng Book Ser 3:681–722CrossRefGoogle Scholar
  20. 20.
    Kazemian S, Bujang BKH, Prasad A, Barghchi M (2011) A state of art review of peat: geotechnical engineering perspective. Int J Phys Sci 6(8):1974–1981Google Scholar
  21. 21.
    Nawarathna THK, De Silva LIN (2014). Applicability of the Limit equilibrium method and the finite element methods in predicting the stability of embankment slopes. Annual session of IESL, pp 11–17Google Scholar
  22. 22.
    Abusharar WS, Zheng J, Baoguo C, Yin J (2009) The performance of an embankment on soft ground reinforced with geosynthetics and pile walls. Geosynth Int 3(4):1–10Google Scholar
  23. 23.
    Bergado DT, Teerawattanasuk C, Youwai S, Voottipruex P (2011) Finite element modeling of hexagonal wire reinforced embankment on soft clay. Can Geotech J 37:1209–1226CrossRefGoogle Scholar
  24. 24.
    Safadoust J, Amiri SN, Esmaeily A (2013) Numerical analysis of reinforced embankment over soft foundation. J Eng Sci Technol Rev 6(3):153–159CrossRefGoogle Scholar
  25. 25.
    Siavoshnia M, Kalantari F, Shakiba A (2010) Assessment of geotextile reinforced embankment on soft clay soil. In: The 1st international applied geological congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, pp 26–28Google Scholar
  26. 26.
    Paravita SW, Daniel T (2015) Analysis of geotextile reinforced road embankment using PLAXIS 2D. In: The 5th international conference of Euro Asia civil engineering forum (EACEF-5), vol 125, pp 358–362Google Scholar

Copyright information

© Indian Geotechnical Society 2019

Authors and Affiliations

  1. 1.Department of Civil EngineeringUniversity of PeradeniyaPeradeniyaSri Lanka

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