Simulation of Soil-Pile Interaction of Steel Batter Piles Penetrated in Sandy Soil Subjected to Pull-Out Loads

Authors: Ameer A. Jebur, William Atherton, Rafid M. Alkhaddar, Edward Loffill

Abstract:

Superstructures like offshore platforms, tall buildings, transition towers, skyscrapers and bridges are normally designed to resist compression, uplift and lateral forces from wind waves, negative skin friction, ship impact and other applied loads. Better understanding and the precise simulation of the response of batter piles under the action of independent uplift loads is a vital topic and an area of active research in the field of geotechnical engineering. This paper investigates the use of finite element code (FEC) to examine the behaviour of model batter piles penetrated in dense sand, subjected to pull-out pressure by means of numerical modelling. The concept of the Winkler Model (beam on elastic foundation) has been used in which the interaction between the pile embedded depth and adjacent soil in the bearing zone is simulated by nonlinear p-y curves. The analysis was conducted on different pile slenderness ratios (lc⁄d) ranging from 7.5, 15.22 and 30 respectively. In addition, the optimum batter angle for a model steel pile penetrated in dense sand has been chosen to be 20° as this is the best angle for this simulation as demonstrated by other researcher published in literature. In this numerical analysis, the soil response is idealized as elasto-plastic and the model piles are described as elastic materials for the purpose of simulation. The results revealed that the applied loads affect the pullout pile capacity as well as the lateral pile response for dense sand together with varying shear strength parameters linked to the pile critical depth. Furthermore, the pile pull-out capacity increases with increasing the pile aspect ratios.

Keywords: Slenderness ratio, soil-pile interaction, winkler model (beam on elastic foundation), pull-out capacity.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1124571

References:

[1] M.J, T., Pile Design and Construction, ed. U.K. London. 2014, London, U.K: Sixth Edution, E & FN Spon, pp.588.
[2] Das, B.M., Principles of Foundation Engineering, ed. EighthEdition. 2015, United State of America: Global Engineering; Nelson Education LTD, pp. 896. pp. 896.
[3] Gaaver, K.E., Uplift capacity of single piles and pile groups embedded in cohesionless soil. Alexandria Engineering Journal, 2013. 52(3): p. pp. 365-372.
[4] American Petroleum Institute, Recommended Practice for Planning, Pesigning and Constructing Fixed offshore Platforms Working Stress Design, Errata and Supplement, 2007.
[5] Lehane, B.M. and K.G. Gavin, Base Resistance of Jacked Pipe Piles in Sand. Journal of Geotechnical and Geoenvironmental Engineering 2001. 2001.127: p. 473-480.
[6] Chen, Y. and F.H. Kulhawy, Evaluation of drained axial capacity of drilled shafts, in: Proc., Deep Foundations 2002. Geotech. Spec. Publication No. 116, vol. 2, ASCE, 2002: p. pp. 1200–1214.
[7] O’Neill, M.W. and L.C. Reese, Drilled Shafts: Construction Procedures and Design Methods. Publication No. FHWA-IF-99-025, U.S. Dept. of Transportation, Washington, 1999. vol. II.
[8] Mroueh, H. and I. Shahrour, Numerical Analysis of the Response of Battered Piles to Inclined Pullout Loads. Int. J. Numer. Anal. Meth. Geomech. 33, 2008: p. pp. 1277–1288.
[9] Winkler, E.H.D., Die Lehre von Elastizitat und Festigkeit. H. Dominicus, Prague, Czechoslovakia., 1867.
[10] Ensoft, I., LPILE Plus 5.0. Ensoft, Inc. 2005.
[11] Nunez, I., et al., Driving and Tension Loading of Piles in Sand on a Centrifuge. In: Corte JF, editor. Centrifuge´ 88: Proceedings International Conference Centrifuge. Paris (Rotterdam): A.A. Balkema, 1988: p. pp. 353–362.
[12] Remaud, D., Pieux Sous Charges Latérales: Etude Expérimentale De L’effet De Groupe. PhD thesis. Université de Nantes; French, 1999.
[13] American Society for Testing and Materials Specifications, 2012.
[14] Robinsky, E.I. and C.F. Morrison, Sand displacement and compaction around model friction piles. Canadian Geotechnical Journal 1964: p. 1 (2), pp. 81–93.
[15] Gere, J.M. and S.P. Timoshenko, Mechanics of materials 1997: p. xvi, 912 p. 4th eddition