This paper presents a method to obtain the constitutive relationships of sands from in-situ drained self-boring pressuremeter tests. Plane-strain conditions and Rowe's stress-dilatancy theory are assumed to hold to determine effective stress paths. The proposed method appears to correctly render the response behavior of loose to dense sands. The two parameters that are needed to interpret the pressuremeter expansion curves are the initial effective horizontal pressure at rest, σ′ho, and the effective friction angle of the sands at constant volume, φ′cv. The proposed method allows to draw drained stress paths on a Mohr- Coulomb diagram, from which both the peak friction angle φ′p and the peak dilatancy angle ν′p may be determined. In addition, as Rowe's dilatancy theory is used in the analyses, it is possible to obtain the variation of the volumetric strain as a function of the shear strain. Finally, for the numerical solution procedure followed in the paper, the original pressuremeter curves used were first discretized and then approximated with a polynomial of degree 4 to 5. This allowed to considerably reduce the scatter in the results.
Proper investigation of marine sediments requires a combination of cone penetration and pressuremeter testing supplemented by a laboratory program that is consistent with the in-situ data. Neither insitu nor laboratory testing on their own is sufficient to define the sand strength and behavior. In recent years the self-boring pressuremeter (SBPM) test has become one of the most useful field tests in geotechnical engineering. The interpretation of a SBPM test in clay is straightforward, especially since the investigations of Baguelin et al. (1972), Ladanyi (1972), and Palmer (1972), which showed that it was not necessary to postulate the type of constitutive relationship in order to obtain the shear strength of the material.
