Geomechanics and Engineering

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Bearing capacity and failure mechanism of skirted footings

  • Shukla, Rajesh P. (Department of Civil Engineering, National Institute of Technology) ;
  • Jakka, Ravi S. (Department of Earthquake Engineering, IIT Roorkee)
  • Received : 2019.06.21
  • Accepted : 2022.03.15
  • Published : 2022.07.10
⟨ Previous Next ⟩

Abstract

The article presents the results of finite element analyses carried out on skirted footings. The bearing capacity increases with the provision of the flexible and rigid skirt, but the effectiveness varies with various other factors. The skirts are more efficient in the case of cohesionless soils than cohesive and c-ϕ soils. Efficiency reduces with an increase in the soil strength and footing depth. The rigid skirt is relatively more efficient compared to the flexible skirt. In contrast, to the flexible skirt, the efficiency of the rigid skirt increases continuously with skirt length. The difference in the effectiveness of both skirts becomes more noticeable with an increase in the strength parameters, skirt length, and footing depth. The failure mechanism also changes significantly with the inclusion of a rigid skirt. The rigid skirt behaves as a solid embedded footing, and the failure mechanism becomes confined with an increase in the skirt length. Few small-scale laboratory tests were carried out to study the flexible and rigid skirt and verify the numerical study results. The numerical analysis results are further used to develop nonlinear equations to predict the enhancement in bearing capacity with the provision of the rigid and flexible skirts.

Keywords

References

  1. Acosta-Martinez, H.E., Gourvenec, S.M. and Randolph, M.F. (2008), "An experimental investigation of a shallow skirted foundation under compression and tension", Soils Found., 48(2), 247-254. https://doi.org/10.3208/sandf.48.247.
  2. Al-Aghbari, M.Y. and Mohamedzein, Y.A. (2004), "Model testing of strip footings with structural skirts", Proceedings of the Institution of Civil Eng.-Ground Improvement, 8(4), 171-177. https://doi.org/10.1680/grim.8.4.171.41844.
  3. l-Aghbari, M.Y. and Mohamedzein, Y.A. (2006), "Improving the performance of circular foundations using structural skirts", Proceedings of the Institution of Civil Engineers-Ground Improvement, 10(3), 125-132. https://doi.org/10.1680/grim.2006.10.3.125.
  4. Al-Aghbari, M.Y. and Mohamedzein, Y.E. (2004), "Bearing capacity of strip foundations with structural skirt", Geotech. Geol. Eng., 22(1), 43-57. https://doi.org/10.1023/B:GEGE.0000013997.79473.e0.
  5. Al-Aghbari, M.Y. and Mohamedzein, Y.E.A. (2018), "The use of skirts to improve the performance of a footing in sand", Int. J. Geotech. Eng., 1-8. https://doi.org/10.1080/19386362.2018.1429702.
  6. Al-Aghbari, M.Y. and Dutta, R.K. (2008), "Performance of square footing with structural skirt resting on sand", Geomech. Geoeng., 3(4), 271-277. https://doi.org/10.1080/17486020802509393.
  7. Bienen, B., Gaudin, C., Cassidy, M.J., Rausch, L., Purwana, O.A., and Krisdani, H. (2012), "Numerical modelling of a hybrid skirted foundation under combined loading", Comput. Geotech., 45, 127-139. https://doi.org/10.1016/j.compgeo.2012.05.009.
  8. Bransby, M.F. and Yun, G.J. (2009), "The undrained capacity of skirted strip foundations under combined loading", Geotechnique, 59(2), 115-125. https://doi.org/10.1680/geot.2007.00098.
  9. Bransby, M.F. and Randolph, M.F. (1999), "The effect of skirted foundation shape on response to combined V-M-H Loadings", Int. J. Offshore Polar Eng., 9(3), 214-218.
  10. Chen, W. and Randolph, M.F. (2007), "External radial stress changes and axial capacity for suction caissons in soft clay", Geotechnique, 57(6), 499-511. https://doi.org/10.1680/geot.2007.57.6.499.
  11. Chwala, M. (2021), "Upper-bound approach based on failure mechanisms in slope stability analysis of spatially variable c-φ soils", Comput. Geotechnics, 135, 104170. https://doi.org/10.1016/j.compgeo.2021.104170.
  12. Chwala, M. and Pula, W. (2020), "Evaluation of shallow foundation bearing capacity in the case of a two-layered soil and spatial variability in soil strength parameters", PloS one, 15(4), e0231992. https://doi.org/10.1371/journal.pone.0231992.
  13. Drescher, A. and Detournay, E. (1993), "Limit load in translational failure mechanisms for associative and non-associative materials", Geotechnique, 43(3), 443-456. https://doi.org/10.1680/geot.1993.43.3.443
  14. Eid, H.T. (2013), "Bearing capacity and settlement of skirted shallow foundations on sand", Int. J. Geomech., 13(5), 645-652. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000237
  15. Fenton, G.A. and Griffiths, D.V. (2003), "Bearing-capacity prediction of spatially random c φ soils", Can. Geotech. J., 40(1), 54-65. https://doi.org/10.1139/t02-086
  16. Gray, D.H. and Al-Refeai, T. (1986), "Behavior of fabric vs. fiber-reinforced sand", J. Geotech. Eng. -ASCE, 112(8), 804-820. https://doi.org/10.1061/(ASCE)0733-9410(1986)112:8(804).
  17. Hansen, J.B. (1970), A revised and extended formula for bearing capacity, Bulletin 28, 5-11. Copenhagen: Danish Geotechnical Institute.
  18. Hu, Y., Randolph, M.F. and Watson, P.G. (1999), "Bearing response of skirted foundation on nonhomogeneous soil", J. Geotech. Geoenviron. Eng., 125(11), 924-935. https://doi.org/10.1061/(ASCE)1090-0241(1999)125:11(924).
  19. Huang, C.C. and Tatsuoka, F. (1994), "Stability analysis for footings on reinforced sand slopes", Soils Found., 34(3), 21-37. https://doi.org/10.3208/sandf1972.34.3_21.
  20. Khatri, V.N., Debbarma, S.P., Dutta, R.K. and Mohanty, B. (2017), "Pressure-settlement behavior of square and rectangular skirted footings resting on sand", Geomech. Eng., 12(4), 689-705. https://doi.org/10.12989/gae.2017.12.4.689.
  21. Krabbenhoft, K., Lyamin, A.V. and Sloan, S.W. (2007), "Formulation and solution of some plasticity problems as conic programs", Int. J. Solids Struct., 44(5), 1533-1549. https://doi.org/10.1680/geot.2007.57.8.647.
  22. Krabbenhoft, K., Lyamin, A.V. and Sloan, S.W. (2008), "Three-dimensional Mohr-Coulomb limit analysis using semidefinite programming", Commun. Numer. Method. Eng., 24(11), 1107-1119. https://doi.org/10.1002/cnm.1018.
  23. Lemaitre, J. (Ed.) (2001), Handbook of Materials Behavior Models, Three-Volume Set: Nonlinear Models and Properties.
  24. Lyamin, A.V., Salgado, R., Sloan, S.W. and Prezzi, M. (2007), "Two-and three-dimensional bearing capacity of footings in sand", Geotechnique, 57(8), 647-662. https://doi.org/10.1680/geot.2007.57.8.647.
  25. Makrodimopoulos, A. and Martin, C.M. (2006), "Lower bound limit analysis of cohesive- frictional materials using second-order cone programming", Int. J. Numer. Method. Eng., 66(4), 604-634. https://doi.org/10.1002/nme.1567.
  26. Makrodimopoulos, A. and Martin, C.M. (2007), "Upper bound limit analysis using simplex strain elements and second- order cone programming", Int. J. Numer. Anal. Method. Geomech., 31(6), 835-865. https://doi.org/10.1002/nag.567.
  27. Mana, D.S., Gourvenec, S.M., Randolph, M.F. and Hossain, M.S. (2012), "Failure mechanisms of skirted foundations in uplift and compression", Int. J. Phys. Model. Geotech., 12(2), 47-62. https://doi.org/10.1680/ijpmg.11.00007.
  28. Mana, D.S., Gourvenec, S. and Martin, C.M. (2013), "Critical skirt spacing for shallow foundations under general loading", J. Geotech. Geoenviron., 139(9), 1554-1566. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000882.
  29. Mana, D.S., Gourvenec, S. and Randolph, M.F. (2014), "Numerical modelling of seepage beneath skirted foundations subjected to vertical uplift", Geotech., 55, 150-157. doi.org/10.1016/j.compgeo.2013.08.007
  30. Meyerhof, G.G. (1965), "Shallow foundations", J. Soil Mech. Found. Eng. ASCE, 91(2), 21-31. https://doi.org/10.1061/JSFEAQ.0000719
  31. Michalowski, R.L. (1997), "An estimate of the influence of soil weight on bearing capacity using limit analysis", Soils Found., 37(4), 57-64. https://doi.org/10.3208/sandf.37.4_57.
  32. Michalowski, R.L. (2001), "Upper-bound load estimates on square and rectangular footings", Geotechnique, 51(9), 787-798. https://doi.org/10.1680/geot.2001.51.9.787.
  33. Nazir, A.K. and Azzam, W.R. (2010), "Improving the bearing capacity of footing on soft clay with sand pile with/without skirt", Alexandria Eng. J., 49, 371-377. https://doi.org/10.1016/j.aej.2010.06.002.
  34. Optum G2. Computational Engineering, Copenhagen, Denmark.
  35. Park, J.S., Park, D. and Yoo, J.K. (2016), "Bearing capacity of bucket foundations in sand", Ocean Eng., 121, 453-461. https://doi.org/10.1016/j.oceaneng.2016.05.056.
  36. Pula, W. and Chwala, M. (2018), "Random bearing capacity evaluation of shallow foundations for asymmetrical failure mechanisms with spatial averaging and inclusion of soil self-weight", Comput. Geotech., 101, 176-195. 10.1016/j.compgeo.2018.05.002
  37. Randolph, M.F. and Watson, P.G. (1999), "Bearing response of skirted foundation on nonhomogeneous soil", J. Geotech. Geoenviron. Eng., 24-934. https://doi.org/10.1061/(ASCE)1090-0241(1999)125:11(924).
  38. Sajjad, G. and Masoud, M. (2018), "Study of the behaviour of skirted shallow foundations resting on sand", Int. J. Phys. Model. Geotech., 18(3), 117-130. https://doi.org/10.1680/jphmg.16.00079.
  39. Saleh, N.M., Alsaied, A.E. and Elleboudy, A.M. (2008), "Behavior of skirted strip footing under eccentric load", Proceedings of the 17th Int. Conf. on Soil Mech. and Geotechnical Eng., 586-589.
  40. Selmi, M., Kormi, T., Hentati, A. and Ali, N.B.H. (2019), "Capacity assessment of offshore skirted foundations under HM combined loading using RFEM", Comput. Geotech., 114, 103148. https://doi.org/10.1016/j.compgeo.2019.103148.
  41. Shukla, R.P. (2019), Bearing Capacity of Skirted Footing on Slopes. Ph.D. Dissertation. Indian Institute of Technology Roorkee, Roorkee, India.
  42. Shukla, R.P. (2022), "Bearing capacity of skirted footing subjected to inclined loading", Mag. Civil Eng., 110(2), 1-11, https://doi.org/10.34910/MCE.110.12.
  43. Shukla, R.P. and Jakka, R.S. (2018), "Critical setback distance for a footing resting on slopes under seismic loading", Geomech. Eng., 15(6), 1193-1205. https://doi.org/10.12989/gae.2018.15.6.1193.
  44. Shukla, S.K. (2017). Fundamentals of Fibre-Reinforced Soil Engineering, Springer Nature Singapore Pld.
  45. Soubra, A. H. (1999), "Upper-bound solutions for bearing capacity of foundations", J. Geotech. Geoenviron. Eng., 125(1), 59-68. https://doi.org/10.1061/(ASCE)1090-0241(1999)125:1(59).
  46. Stergiou, T., Terzis, D. and Georgiadis, K. (2015), "Undrained bearing capacity of tripod skirted foundations under eccentric loading", Geotechnik, 38(1), 17-27. https://doi.org/10.1002/gete.201400029.
  47. Swiss Standard SN 670 010b (2007), Characteristic coefficients of soils, Association of Swiss Road and Traffic Engineers Minnesota Dept. of Transportation, Pavement Design.
  48. Tani, K. and Craig, W.H. (1995), "Bearing capacity of circular foundations on soft clay of strength increasing with depth", Soils Found., 35(4), 21-35. https://doi.org/10.3208/sandf.35.4_21.
  49. Terzaghi, K. (1943), Theoretical soil mechanics, Wiley, New York.
  50. Valore, C., Ziccarelli, M. and Muscolino, S.R. (2017), "The bearing capacity of footings on sand with a weak layer", Geotech. Res., 4(1), 12-29. https://doi.org/10.1680/jgere.16.00020.
  51. Vesic, A.S. (1973), "Analysis of ultimate loads of shallow foundations", J. Soil Mech. Found. Division, 99(1), 45-73. https://doi.org/10.1061/JSFEAQ.0001846.
  52. Vulpe, C. (2015), "Design method for the undrained capacity of skirted circular foundations under combined loading: effect of deformable soil plug", Geotechnique, 65(8), 669-683. https://doi.org/10.1680/geot.14. P.200.
  53. Wakil, A.Z.E. (2013), "Bearing capacity of skirt circular footing on sand", Alexandria Eng. J., 52, 359-364. https://doi.org/10.1016/j.aej.2013.01.007.
  54. Wang, Y.J., Yin, J.H. and Chen, Z.Y. (2001), "Calculation of bearing capacity of a strip footing using an upper bound method", Int. J. Numer. Anal. Method. Geomech., 25(8), 841-851. https://doi.org/10.1002/nag.151.
  55. Yan, Z., Liu, R. L., Lv, P. and Zhang, H.Q. (2020), "Model tests on jacking installation and lateral loading performance of a new skirted foundation in sand", Ocean Eng., 197, 106914. https://doi.org/10.1016/j.oceaneng.2019.106914.
  56. Yun, G. and Bransby, M.F. (2007b), "The undrained vertical bearing capacity of skirted foundations", Soils Found., 47(3), 493-506. https://doi.org/10.3208/sandf.47.493.
  57. Zhang, P. and Ding, H. (2011), "Bearing capacity of the bucket spudcan foundation for offshore jack-up drilling platforms", Petroleum Exploration and Development, 38(2), 237-242. https://doi.org/10.1016/S1876-3804(11)60029-3.
  58. Ziccarelli, M., Valore, C., Muscolino, S.R. and Fioravante, V. (2017), "Centrifuge tests on strip footings on sand with a weak layer", Geotech. Res., 4(1), 47-64. https://doi.org/10.1680/jgere.16.00021.