Improvement in uplift capacity of horizontal circular anchor plate in undrained clay by granular column

  • Bhattacharya, Paramita (Department of Civil Engineering, Indian Institute of Technology Kharagpur) ;
  • Roy, Anamitra (Department of Civil Engineering, Indian Institute of Technology Kharagpur)
  • Received : 2015.06.03
  • Accepted : 2016.02.10
  • Published : 2016.05.25


A numerical study has been conducted to examine the improvement achieved in the ultimate pullout capacity of horizontal circular anchor plates embedded in undrained clay, by constructing granular columns of varying diameter over the anchor plates. The analysis has been carried out by using lower bound theorem of limit analysis and finite elements in combination with linear programming. The improvement in uplifting capacity of anchor plate is expressed in terms of an efficiency factor (${\xi}$). The efficiency factor (${\xi}$) has been defined as the ratio of ultimate vertical pullout capacity of anchor plate having diameter D embedded in soft clay reinforced by granular column to the vertical pullout capacity of the anchor plate with same diameter D embedded in soft clay only. The variation of efficiency factor (${\xi}$) for different embedment ratios and different diameter of granular column has been studied considering a wide range of softness of clay and different value of soil internal friction angle (${\phi}$) of the granular material. It is observed that ${\xi}$ increases with an increase in diameter of the granular column ($D_t$) and increase in friction angle of granular material. Also, the effectiveness of the usage of granular column increases with decrease in cohesion of the clay.


  1. Bhattacharya, P. and Kumar, J. (2015), "Vertical uplift capacity of a circular anchor plates", Geotech. Eng. J. SEAGS & AGSSEA, 46(3), 105-110.
  2. Bishop, A.W. (1966), "The strength of soils as engineering materials", Geotechnique, 16(2), 89-128.
  3. Bottero, A., Negre, R., Pastor, J. and Turgeman, S. (1980), "Finite element method and limit analysis theory for soil mechanics problem", Comput. Method. Appl. Mech. Eng., 22(1), 131-149.
  4. Bouassida, M. and Hadhri, T. (1995), "Extreme loads of soils reinforced by columns: The case of an isolated column", Soils Found., 35(1), 21-35.
  5. Bouassida, M. and Porbaha, A. (2004), "Ultimate bearing capacity of soft clays reinforced by a group of columns-application to a deep mixing technique", Soils Found., 44(3), 91-101.
  6. Bouassida, M., Jellali, B. and Lyamin, A. (2015), "Ultimate bearing capacity of a strip footing on ground reinforced by a trench", Int. J. Geomech., 15(3), 06014021. DOI: 10.1061/(ASCE)GM.1943-5622.0000418
  7. Davis, E.H. (1968), Theories of Plasticity and Failure of Soil Masses in Soil Mechanics: Selected topics, (I. K. Lee Ed.), Elsevier, New York, USA, pp. 341-354.
  8. Demir, A. and Ok, B. (2015), "Uplift response of multi-plate helical anchors in cohesive soil", Geomech. Eng., Int. J., 8(4), 615-630.
  9. Haar, A. and von Karman, Th. (1909), "ZurTheorie der Spannungs-zustaende in Plastischen und StanartigenMedien, Nachrichten der AkademicWissenschaften in Gottingen", Mathematisch-Physikalische, Klasse, 204-218.
  10. Keskin, M.S. (2015), "Model studies of uplift capacity behavior of square plate anchors in geogridreinforced sand", Geomech. Eng., Int. J., 8(4), 595-613.
  11. Khatri, V.N. and Kumar, J. (2009a), "Vertical uplift resistance of circular plate anchors in clays under undrained condition", Comput. Geotech., 36(8), 1352-1359.
  12. Khatri, V.N. and Kumar, J. (2009b), "Bearing capacity factor $N_{\gamma}$ for a rough conical footing", Geomech. Eng., Int. J., 1(3), 205-218.
  13. Kumar, J. and Khatri, V.N. (2011), "Bearing capacity factors of circular foundations for a general c-${\phi}$ soil using static finite element analysis", Int. J. Numur. Anal. Methods Geomech., 35(3), 393-405.
  14. Kumar, P.B.R. and Rao, R.N. (2000), "Increasing pull-out capacity of granular pile anchors in expansive soils using base geosynthetics", Can. Geotech. J., 37(4), 870-881.
  15. Kupferman, M. (1965), "The vertical holding capacity of marine anchors in clay subjected to static and cyclic loading", M.Sc. Dissertation; University of Massachusetts, Amherst, MA, USA.
  16. Merifield, R.S., Lyamin, A.V., Sloan, S.W. and Yu, H.S. (2003), "Three-dimensional lower bound solutions for stability in plate anchors for clay", J. Geotech. Geoenviron. Eng., ASCE, 129(3), 243-253.
  17. Merifield, R.S., Lyamin, A.V. and Sloan, S.W. (2006), "Three dimensional lower bound solutions for the stability of plate anchors in sand", Geotechnique, 56(2), 123-132.
  18. Niroumand, H. and Kassim, K.A. (2014), "Uplift response of circular plate as symmetrical anchor plates in loose sand", Geomech. Eng., Int. J., 6(4), 321-340.
  19. O'Kelly, B.C., Brinkgreve, R.B.J. and Sivakumar, V. (2014), "Pullout resistance for granular anchors in clay for undrained condition", Soils Found., 54(6), 1145-1158.
  20. Rao, S.A., Phanikumar, B.R., Babu R.D. and Suresh, K. (2007), "Pullout behavior of granular pile-anchors in expansive clay beds in situ", J. Geotech. Geoenviron. Eng., ASCE, 133(5), 531-538.
  21. Sivakumar, V., O'Kelly, B.C., Madhav, M.R., Moorhead, C. and Rankin, B. (2013), "Granular anchors under vertical loading - axial pull", Can. Geotech. J., 133(5), 531-538.
  22. Sloan, S.W. (1988), "Lower bound limit analysis using finite elements and linear programming", Int. J. Numur. Anal. Methods Geomech., 12(1), 61-77.
  23. Sloan, S.W. (2013), "Geotechnical stability analysis", Geotechnique, 63 (7), 531-572.
  24. Yu, H.S. (2000), Cavity Expansion Methods in Geomechanics, Kluwer Academic Publishers, Dodrecht, The Netherlands.