Very small strain stiffness of Lisbon Miocene clayey formation from in situ tests

• Type: Article in International Conference Proceedings Book
• Date: 2015

Authors

Laranjo, ML (Author) Other; Jorge Manuel C. Machado de Carvalho (Author) FEUP; Fernandes, MM (Author) Other; Fonseca, AV (Author) Other

Conference proceedings International

Title: Proceedings of the XVI ECSMGE Geotechnical Engineering for Infrastructure and Development

Pages: 2975-2980

XVI ECSMGE Geotechnical Engineering for Infrastructure and Development

Edinburgh, 13-17 September

Indexing

Scopus - 2 Citations

Other information

Authenticus ID: P-00K-EMB

Abstract (EN): Lisbon Miocene clays are part of the Miocene Series, formed in the Lower Tagus Basin, in the western margin of the Iberian Plate. The Miocene Series is around 300 m thick and comprises several geological formations that include hard soils and soft rocks from both continental and marine origins. One of the main clayey formations is Prazeres clay, a highly consolidated clayey formation that encompasses an important part of Lisbon subsoil, including areas of historical interest. Included in an ongoing investigation on the physical and mechanical characterization of Lisbon Miocene clays, in situ tests were performed, namely cross-hole seismic tests (CHT) and self-boring pressuremeter tests (SBPT). Although SBPT minimizes disturbance, there are differences in measurements of stiffness parameters from SBPT and CHT, with implications on small strain stiffness G0. This paper presents a discussion on the anisotropy of these properties, obtained from shear wave velocity in CHT tests under distinct travel paths, frequency bands and polarization directions. The paper also discusses some correlations that can be established between the small strain stiffness (G0) obtained from CHT and from expansion-contraction cycles from SBPT taking into account the actual test stress-strain conditions.

Language: English

Type (Professor's evaluation): Scientific