Full-scale behavior of vibratory driven piles in Montoir

Within the framework of the French National Project on vibratory driving, it was decided to investigate the full-scale behavior of vibratory driven piles in the harbor of Montoir, located at the estuary of the Loire River. The subsoil consists of alluvial sandy deposits overlying sandy mud clay. Two 339 mm closed-end tubes, 31 m long, were vibratory driven to 19 m depth where the refusal was observed. To investigate dynamic resistance, one of the tubes was impact driven for the last meter by a diesel hammer. The tubes were both instrumented with accelerometers and strain gauges positioned at the top and at the pile point. The entirely vibrodriven pile was statically loaded after a delay of 3 weeks. In this paper, the authors report on the site investigation, the observations made during the driving and the results of the static loading test. Bearing capacity of the vibratory driven pile is compared to previous tests on CFA and impact driven piles.