Shear strength of soft soil determined from element tests and penetration tests

The shear strength of soft soils such as clay or calcareous silt is an important parameter for the design of foundations in such sediments. In the field, the cone penetrometer test is the primary tool for estimating the shear strength, while in the laboratory, the strength is determined from element tests such as triaxial or simple shear tests. Correlations are then established between the results of the field and laboratory tests for design purposes. However, as is well known, the laboratory measurements may vary due to the type of test used (triaxial compression or extension, or simple shear) and the consolidation conditions (isotropic or anisotropic). The paper presents a comprehensive investigation of the shear strength of kaolin clay and a calcareous silt from the North West Shelf of Australia, involving element tests and model tests and comparisons are made between the results of the different tests.