Ménard pressuremeter modulus: ASTM D4719 and EN ISO 22476-4

Updated: 2026-08-04 · ISKRIT

A pressuremeter expands a cylindrical cavity in the borehole wall and measures pressure against volume or radius. The Ménard modulus comes from the straight, pseudo-elastic part of that curve, and its formula contains one detail that is routinely got wrong.

The formula

EM = 2 (1 + ν) · rm · Δp / Δr

with ν taken as 0.33 by convention in both ASTM D4719 and EN ISO 22476-4, so the leading factor is 2.66. The detail is rm: it is the mean cavity radius over the pseudo-elastic segment, not the initial radius of the uninflated probe. Substituting the initial radius systematically underestimates the modulus, and the error grows with how much the cavity had already expanded before the linear segment began.

Worked

Mean cavity radius 3.5 cm over the linear segment. A pressure increment of 0.4 MPa produces 0.35 cm of radial expansion:

EM = 2.66 · 3.5 · 0.4 / 0.35 = 10.6 MPa

The other tradition

Russian GOST 20276 does not use the elasticity solution. It applies an empirical coefficient from tabulated values depending on soil type and test arrangement, together with the initial radius, and reports a deformation modulus intended to match plate load results. So the same expansion curve gives two different, both legitimate, moduli depending on which standard the report cites, and the difference is not a rounding matter.

Reading the curve

Three zones appear on a pressuremeter curve: recompression of the disturbed borehole wall, the pseudo-elastic straight segment, and plastic expansion towards the limit pressure. Only the middle zone belongs in the modulus. Where its ends are placed is an interpretation, and two engineers will disagree by several percent on the same curve, so the segment boundaries belong in the report next to the modulus.

Questions

Is the limit pressure part of the same reading? No, it is a separate result taken from the plastic part, and it is what bearing capacity correlations use.

Does the Poisson convention need justifying? Not when the standard is cited, since 0.33 is built into the definition of the Ménard modulus rather than being an assumption about the soil.

The field testing tool carries both branches: Ménard by ASTM D4719 and EN ISO 22476-4, or the tabulated-coefficient route.