Design And Installation Of Piles In Chalk

Ageing and cyclic behaviour of axially loaded piles driven in chalk

“…Chalk, a highly variable soft biomicrite composed of mainly silt sized crushable CaCO3 particles, is found widespread across Northern Europe and under the North Sea, where thicknesses can exceed 1200m; Clayton et al (2002), Mortimore (2012). While few carefully stage-loaded static load tests have been reported to prove or predict the piles' ability to carry axial loads, low shaft driving resistances (between 0 and 20kPa) have been reported from dynamic driving analyses that suggest low static service capacities (Lord et al, 2002, Vijayvergiya et al, 1977. The Construction Industry Research and Information Association (CIRIA) offers design guidelines based on four pile tests that indicate widely different ultimate unit shaft resistances of 20 to 120kPa for low-medium and high density chalks respectively (Lord et al, 2002).…”

“…While Lord et al (2002) suggested that field set-up (or increase in capacity with time) also takes place with low-medium density chalk, due to pore pressure dissipation and/or internal recementing of the putty annulus around the pile, redox chemical reactions may also play a role. Vijayvergiya et al (1977) reported an 80% increase in dynamic driving resistance over a 60 day pause in an offshore project, while Skov and Denver (1988) interpreted a 383% increase over 13 days from static and dynamic load tests on two concrete piles driven in chalk. Lahrs and Kallias (2013) reported 50% to 60% increases in shaft resistance in chalk over four months from multiple offshore dynamic restrikes on 1.5m diameter piles, but found the shaft capacity of a single pile fell over time when subjected to multiple restrikes and a static test.…”

Behaviour of piles driven in chalk

“…Marked increases in capacity over time, or 'set-up', have also been reported for piles driven in chalk by Vijayvergiya et al (1977), Skov and Denver (1988) and Lahrs and Kallias (2013). Static re-tests by Ciavaglia et al (2017) on piles driven at St Nicholasat-Wade, Kent (see Figure 1) also showed marked shaft set-up.…”

Underwater Geotechnical Foundations

“…Sabine River delta (Grosch and Reese 1980) Offshore Florida calcareous sands ) Offshore Southern California (Mahmood and Reifel 1978) Mississippi Delta (Gulf of Mexico) weak sediments Booth and Garrison 1978) Gulf of Mexico underconsolidated clays to dense sands ) Alaska coastal waters Hawaii calcareous sands Offshore Cuba coral sands Offshore Brazil calcareous soils (Ping et al 1984) Offshore Australia calcareous sands and sandy silts Tan, Parkin, and Yee 1990;) Borneo marine clays Offshore India (Stockard 1986) Offshore China dense sands (Tsien 1986) Arabian Gulf hard clays, dense sands, rocks, and coral Settgast 1980; Gulf of Suez calcareous sands and silts Cheng 1984, Dutt and) North Sea stiff clays North Sea soft clays (Karlsrud and Nadim 1990) North Sea dense sands (Jardine and Overy 1996, Zuidberg and Vergobbi 1996) North Sea boulder clays North Sea chalk (Vijayvergiya, Cheng, and Kolk 1977;Davie, Ehlers, and Antes 1978) 4 Design Considerations…”