Field test of tension piles - on long term behavior

Projekt:

Funktion av dragna pålar i lösa kohesionsjordar för långtidslast

Sammanfattning:
This report presents the results from a field test carried to study the long-term response of driven tension piles in natural soft clays. The study site was located at Marieholm, Gothenburg. This area is characterized for having deep deposits of natural soft clays, extending up to 100 meters deep. A novel loading rig has been developed for application of constant loads over long periods of time.

Generally, tension piles serve as anchor structures that mobilise the bearing capacity by means of shaft friction. This pile type is less common in Swedish on-shore engineering practice, and only a few cases have been studied where the long-term response has been investigated. Existing research, on offshore piles, indicates that the long-term pile response is governed by the creep behaviour in the natural soft soils (St John et al., 1983; Ramalho Ortiga¨ao and M. Randolph, 1983). In the present work similar results have been obtained, i.e. the long-term creep behaviour depends on the load magnitude, which in turn governs the displacement magnitude over time. Furthermore, the bearing capacity is limited by the long-term shear strength of the clay (i.e. quasi-static drained shear strength). Finally, the results suggest that creep rupture can be triggered if the pile is loaded close to this long-term failure limit.

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Författare: Jorge Jannie, Claes Alén
Utgivare: Chalmers Tekniska Högskola
Utgivningsdatum: 2015-12-01
Diarienummer: TRV 2012/45805
ISSN: 1652-8549
Antal sidor: 34
Språk: Engelska
Kontaktperson: Anders Hansson, PRtv