Stiffness Decay in Structured Soils by Seismic Dilatometer

• Type: Article in International Scientific Journal
• Date: 2020

Authors

Rodrigues, C (Author) Other; Nuno Mateus (Author) FCUP; Amoroso, S (Author) Other; Cruz, M (Author) Other

Journal

Title: Geotechnical Testing Journal

Vol. 43

Pages: 1003-1021

ISSN: 0149-6115

Publisher: American Society for Testing and Materials

Indexing

ISI Web of Knowledge - 5 Citations

Scopus - 5 Citations

Other information

Authenticus ID: P-00R-252

DOI: 10.1520/gtj2180352

Abstract (EN): The small-strain stiffness modulus G(o) is not directly applicable to evaluate deformation in most practical engineering problems, and therefore, nonlinear soil behavior curves have been developed in terms of Young modulus E or shear modulus G. These curves were successfully obtained for sedimentary soils, while for residual soils, the available data from intertional community is still scarce. Residual soils are considered structured soils and often classified as problematic soils since they do not fit into the behavior of remolded or unstructured soils. In fact, the role of bonding and fabric affects both the strength and the stiffness of the soil. This article illustrates the use of the seismic dilatometer test (SDMT) for the determination of in situ stiffness decay curves with strain level (G-gamma curves or similar) in a granitic residual soil of the Northeastern region of Portugal (Guarda), showing its adequacy to solve these kinds of problems. In situ and laboratory tests were performed on these granitic residual soils. The adopted approach relies on the ability of SDMT to provide a small-strain modulus G(0) (from the shear wave velocity V-s) and a "working strain" modulus G(DMT) (derived from the constrained modulus MDMT in accordance with the theory of elasticity). Thus, in situ G-gamma decay curves were tentatively constructed by fitting curves through these two points using a hyperbolic model. However, it was observed that the results obtained by the hyperbolic model for the cemented soils are not satisfactory. Based on the SDMT parameters, a logistic curve was derived for the reproduction of reference stiffness curves obtained from the triaxial test results.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 19