3. SITE 1071
Position: 39°22.9446′N, 72°43.6830′W Start hole: 1300 hr, 23 June 1997 End hole: 0355 hr, 24 June 1997 Time on hole: 14.92 hr Seafloor (drill pipe measurement from rig floor, mbrf): 99.4 Total depth (drill pipe measurement from rig floor, mbrf): 151.3 Distance between rig floor and sea level (m): 11.2 Water depth (drill pipe measurement from sea level, m): 88.2 Penetration (mbsf): 51.9 Coring totals: Type: APC Number: 7 Cored: 36.3 m Recovered: 27.75 m (76.45%)
U.S. Geological Survey Core Drilling on the Atlantic Shelf
The first broad program of scientific shallow drilling on the U.S. Atlantic continental shelf has delineated rocks of Pleistocene to Late Cretaceous age, including phosphoritic Miocene strata, widespread Eocene carbonate deposits that serve as reflective seismic markers, and several regional unconformities. Two sites, off Maryland and New Jersey, showed light hydrocarbon gases having affinity to mature petroleum. Pore fluid studies showed that relatively fresh to brackish water occurs beneath much of the Atlantic continental shelf, whereas increases in salinity off Georgla and beneath the Florida-Hatteras slope suggest buried evaporitic strata. The sediment cores showed engineering properties that range from good foundation strength to a potential for severe loss of strength through interaction between sediments and man-made structures.
On the use of the Hardening Soil Small Strain model in geotechnical practice
This article highlights the importance of using advanced constitutive soil models in numerical modelling as daily geotechnical practice. In this context, the Hardening Soil (HS) model is presented as the most advanced soil model implemented in the ZSoil finite element code. The article recalls the basic features of the HS model and it explains their role in numerical simulations. The role of pre-failure non-linear behaviour of soils is also discussed. An application of the HS model is illustrated on typical geotechnical problems such as retaining wall excavation, tunnel excavation and undrained loading followed by consolidation.