Bi-directional testing of bored piles in chalk
Bi-directional testing of bored piles in chalk
Large diameter bored piles (Ø1800 mm) will be used as foundation for a new railway bridge crossing Guldborgsund between the Danish islands of Falster and Lolland. The ground conditions at site are dominated by 10-15 m of glacial and late- postglacial deposits above relatively soft Cretaceous chalk. The experience with bored piles in chalk in Denmark is limited and a conservative design approach would have to be used due to lack of testing. Therefore, two full- scale, instrumented piles (26m and 31m long) were constructed and tested using bi-directional loading by means of O-cell technology. The piles were instrumented with tell-tales and strain gauges to allow for determination of the mobilized unit shaft resistance as function of depth and soil type. The piles were loaded to 22.5 MN and 30 MN, respectively, which significantly exceeded the capacity predicted by normal design methods. Based on calibration of an -method for shaft resistance versus local CPT profiles, it was possible to establish a site-specific design model allowing for optimization of the production piles.
M. Roed; Jorgen Steen Steenfelt; Ole Hededal
18th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE2024)
A - New developments on structural design
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