Evaluation of Bearing Capacity of Vertically Loaded Strip Piled-Raft Embedded in Soft Clay

Authors: Seyed Abolhasan Naeini, Mohammad Hosseinzade

Abstract:

Settlement and bearing capacity of a piled raft are the two important issues for the foundations of structures built on coastal areas from the geotechnical engineering point of view. Strip piled raft as a load carrying system can reduce the possible extensive consolidation settlements and improve bearing capacity of structures in soft ground. The aim of this research was to evaluate the efficiency of strip piled raft embedded in soft clay. The efficiency of bearing capacity of strip piled raft foundation has been evaluated numerically in two cases; in the first case, the cap is placed directly on the ground surface and in the second, the cap is placed above the ground. Regarding to the fact that the geotechnical parameters of the soft clay are considered at low level, low bearing capacity is expected. The length, diameter and axe-to-axe distance of piles were the parameters which varied in this study to find out how they affected the bearing capacity. Results indicate that increasing the length and the diameter of the piles increase the bearing capacity.

Keywords: Soft clay, Strip piled raft, Bearing capacity, Settlement.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1336937

References:

[1] H. G. Poulos "Methods of analysis of piled raft foundations", A report prepared on behalf of technical committee TC18 on piled foundations.
[2] J. Lee, Y .Kim, J .Sangseom "Three-dimensional analysis of bearing behavior of piled raft on soft clay", Computers and Geotechnics Volume 37 Issue 1-2, pp. 103-114, 2010,
[3] S.S Liew, S.S Gue and Y.C Tan Gue & Partners Sdn Bhd, Kuala Lumpur, Malaysia. "Design and Instrumentation Results of A Reinforcement Concrete Piled Raft Supporting 2500 Ton Oil Storage Tank On Very Soft Alluvium Deposits”, Ninth International Conference on Piling and Deep Foundations, Nice, 3rd – 5th June, 2002.
[4] J. Novak, L.C. Reese, and S. T. Wang "Analysis of Pile-Raft Foundations with 3D Finite-Element Method", Proceedings of the 2005 Structures congress and 2005 Forensic Engineering Symposium, New York
[5] E.Y.N Oh, D.G Lin., Q.M Bui. , M. Huang, C.Surarak and A.S. Balasubramaniam "Numerical analysis of piled raft foundation in sandy and clayey soils", Proceedings of the 17th International conference on Soil Mechanics and Geotechnical Engineering (ICSMGE 2009): 1159-1162
[6] H.G Poulos "Simplified design procedure for piled raft foundation .Deep Foundation 2002:441-458.
[7] M. Rabiebi .Effect of Pile Configuration and Load Type on Piled Raft", Proceedings of Sessions of Geoshanghai 2010 : Deep Foundations and Geotechnical Insitu testing Geotechnical special publication no. 205:34- 41
[8] L.D Sanctis and Alessandro "A Mandolini Bearing Capacity of Piles Rafts on Soft Clay soils", Journal of Geotechnical and Geoenvironmental Engineering, Vol. 132, No.12, 2006, pp. 1600-1610
[9] Y.K Seo, K.S Choi and S.G Jeong "Design Charts of Piled Raft Foundations on Soft Clay", Proceedings of the 13th International Offshore and Polar Engineering Conference: Honolulu, Hawaii, USA, May 25–30,2003
[10] H. G. Poulos "Piled-raft foundation", design and applications. Geotechnique 2001; 51(2):95–113.
[11] H. G. Poulos "Piled raft and compensated piled raft foundations for soft soil sites", Advances on designing and testing deep foundations. Geotech. Spec. Publ.(ASCE) 2005;129:214
[12] M.F. Randolph" Design of Piled Foundations", Cambridge Univ. Eng. Dept., Res. Rep. Soils TR143, 1983.
[13] C. Viggiani "Pile Groups and Piled Rafts Behavior”. Deep Founds. On Bored and Auger Piles, BAP III, van Impe and Haegman (eds), Balkema, Rotterdam 4998; 77-90.
[14] ABAQUS. User’s manual (ver. 6.5). Pawtucket, (RI): Hibbit, Karlsson & Sorensen; 2004.
[15] J. H. Lee "Nonlinear three dimensional analysis of settlement of piled raft in clay soils", Ph.D. thesis, Yonsei University, Seoul, South Korea; 2007.
[16] R. Katzenbach, U. Arslan, C. Moormann, and O. Reul, "Piled Raft Foundation – Interaction Between Piles and Raft”. Darmstadt Geotechnics, Darmstadt Univ. of Technology1998; No. 4, 279-296.
[17] L.D Sanctis and Alessandro, A Mandolini "Bearing Capacity of Piles Rafts on Soft Clay soils", Journal of Geotechnical and Geoenvironmental Engineering, Vol. 132, No.12, 2006, pp. 1600-1610,
[18] J.Novak, L.C. Reese, and S. T. Wang "Analysis of Pile-Raft Foundations with 3D Finite-Element Method", Proceedings of the 2005 Structures congress and 2005 Forensic Engineering Symposium, New York.
[19] J. Lee, Y .Kim, J .Sangseom "Three-dimensional analysis of bearing behavior of piled raft on soft clay", Geotechnics. Volume 37 Issue 1-2, pp. 103-114 ,2010,
[20] O. Reul and M.F Randolf. "Piled rafts in over consolidated clay", comparison of in situ measurements and numerical analyses, Geotechnique 53, No. 3, 301–315, (2003).