Strength of soft Swiss lacustrine clay: cone penetration and triaxial test data

A new link road is to be constructed top down between parallel cast-in-place pile walls under a series of railway lines in Kreuzlingen, Canton Thurgau, which is an important hub in the regional transportation network. The results of a site investigation on the soft, normally consolidated, post-glacial lacustrine clay deposit underlying the railway lines, including a cone penetration test, undisturbed sampling from an adjacent bore-hole, and laboratory testing, are reported. Strength characteristics of the clay were determined, correlated, and linked to stress history and current stress. The investigation demonstrated a close agreement between strength parameters derived from the laboratory and the in situ testing when a piezocone factor of NkT = 17 was applied. This agreement confirms previous local experience. The results obtained lead to a more differentiated knowledge of the clay deposit, providing valuable data for constitutive modeling. These data will be particularly useful for future local construction work using the observational method and value engineering.