Field Tests of Anchors in Clay II: Predictions and Interpretation

Four field model tests are used to check procedures proposed for the foundation design of suction anchors for offshore tension-leg platforms. The test program contained one static and three cyclic tests in a soft clay deposit. The model was loaded in tension with a load inclination of about 10° from the vertical. The cyclic tests were run with various cyclic load histories, eccentricities, and geometries. Predictions of pull-out capacities and cyclic displacements were made prior to the tests, using procedures developed for and applied in foundation design of offshore gravity platforms. Even though the geometries and the load conditions are quite different for suction anchors and gravity platforms, the procedures gave predicted values in very good agreement with the measurements. This was true for both static and cyclic failure loads and cyclic displacements. The applied calculation procedures are thus well suited for the foundation design of suction anchors.