Inǵnieur, Société Nationale Elf Aquitaine (Production), Pau Cedex,
Professor of civil engineering, MIT, Cambridge, MA
Director, Norwegian Geotechnical Institute, Oslo,
Pages: 16 Published: Jan 1985
The soils surrounding any of the anchorage piles of a tension leg platform (TLP) will be subjected to average (sustained) shear stresses τave of significant magnitude, in addition to the cyclic shear stresses τc associated with fluctuations of environmental loading. In order to investigate their combined effect on the displacement behavior of such a foundation, ten cyclic direct simple shear (DSS) tests were run with constant values of both τave and τc, as were two tests with variable τc. All the conditions of the 1975 Norwegian Geotechnical Institute (NGI) program (Andersen 1976 and Andersen et al, 1980) were followed (Plastic Drammen Clay, Geonor DSS device, and so forth) in order to capitalize upon, and increase, that data base.
The results of the investigation are presented in the form of “three-dimensional strain contour diagrams,” which improve our ability to interpolate, and even extrapolate, the data over a wide range of stress conditions. Furthermore, a procedure is proposed that permits a satisfactory estimation of the clay behavior under the variable cyclic loading imposed.
soils, shear stress, clays, cyclic loading, average shear stress, direct simple shear, soil degradation, tension leg platform, tensile pile
Paper ID: STP36344S