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AN APPROACH FOR ESTIMATING DEFORMATION MODULI FROM
SELF-BORING PRESSUREMETER TEST DATA
RAMESH CHANDRA GUPTA
ABSTRACT During a self-boring pressuremeter test (SBPMT) a
cylindrical cavity is expanded from a finite radius. To determine
undrained shear strength, cu,
of a saturated clay, SBPMT data is analyzed using the cylindrical cavity
expansion theory, and curve fitting methods. At present, there is no
completely consistent and reliable method to estimate the value of modulus
of elasticity. In this paper, an alternative method has been presented to
first estimate cu and limit
pressure, pL, using a
logarithmic model and then determine initial tangent modulus,
Ei, secant modulus at failure,
Esf, and secant modulus at
half the value of (s1-s3)f, E50, using a hyperbolic-model. Values of
cu determined from this method
compare well with those determined from other methods. The predicted
values of Ei and E50 compare well with those determined from
the triaxial tests. The values of E50 also compare well with the values of
modulus determined from unload-reload cycle of SBPMT.
Key words: modulus of deformation, pressuremeter test, shear
modulus, undrained shear strength (IGC: E2/C3)
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