Field Studies on the Axial Capacity of Small Diameter Piles and Ageing Effects in Sands
Résumé
Comprehensive series’ of field pull-out tests have been carried out on small diameter (48 to 60mm outside diameter (OD)) open-ended steel driven piles at Larvik in Norway, Dunkirk in France and Blessington in Ireland to investigate the processes that affect the ageing of axially loaded piles in sand. This paper reports new investigations of the sites’ geotechnical profiles and tension tests on corroded mild steel (MS) piles conducted up to 315 days after driving. The potential influences of: (i) pile diameter, (ii) ground water, (iii) steel type and (iv) installation method are assessed and comparisons made with the ageing responses established in earlier tension tests on larger diameter industrial scale steel driven pipe piles. Steel corrosion and bonding of soil particles are shown to be particularly important with the small diameter piles; the driving process is shown to be significant.