Behavioral Evaluation of Small-Diameter Defective and Intact Bored Piles Subjected to Axial Compression

P.J.R. Albuquerque, J.R. Garcia, O. Freitas Neto, R.P. Cunha, O.F. Santos Junior

Article

Soils and Rocks, São Paulo, 40(2): 109-121, May-August, 2017 | PDF


Abstract

Foundation engineering has continually sought to understand the behavior of piles subjected to loads and their influence on the overall structural behavior. Recently, more load tests are being performed in construction due to the recommendations of the NBR6122/2010 Brazilian code. The available literature offers few reports on pile behavior in a faulty foundation. Therefore, the present study assessed the behavior of a single pile with and without a defect: 5 m long, small-diameter (ϕ = 0.25 m) bored piles were embedded in diabase soil (porous, lateritic and unsaturated) at Experimental Site II (Unicamp). The piles behavior were compared by laboratory tests, numerical analysis using the finite element software LCPC Cesar v.4.07 and experimental results from slow maintained load (SML) tests. Strain gauge instruments were installed at the top and tip of each pile. As predicted by the numerical analyses, when subjected to the first stage of the pile load test, the defective region of the pile failed structurally; however, the pile was still able to resist or “absorb” loading. Factors related to the loading ratio of the foundation, the total and differential displacements and the rotation of the top block were examined. The results obtained in the two analyses (numerical and in situ) were satisfactory and showed significant agreement, providing greater understanding of the complex behavior of this foundation system.


Submitted on October 8, 2016; Final Acceptance on May 5, 2017; Discussion open until December 29, 2017. DOI: 10.28927/SR.402109