Volume 40, N. 3

September-December 2017

The Undrained Strength of Soft Clays Determined from Unconventional and Conventional Tests


Volume 40, N. 3, September-December 2017 | PAPER (16 downloads)


The laboratory fall cone test, considered an unconventional test, was performed to estimate the undrained shear strength of undisturbed samples of Brazilian coastal soft clays with different plasticity index values. The undrained shear strength determined by laboratory fall cone test was compared with the strength determined by conventional field and laboratory tests commonly used to estimate this parameter in cohesive soils: piezocone test, field vane test, unconfined compression test, unconsolidated undrained triaxial compression test and laboratory vane test. The fall cone test undrained shear strength results presented good agreement with the laboratory vane test strength results and reasonable agreement with unconfined compression test strength results. The strength results obtained by laboratory tests were compared with the continuous strength profile estimated from the piezocone test calibrated using the field vane test, and presented good agreement with fall cone test and laboratory vane test strength results. The normalised undrained shear strength was compared with some empirical correlations reported in the literature based on plasticity index, being verified some behaviour similarity.

Keywords: Fall cone test, Soft clays, Undrained shear strength,

Submitted on September 11, 2016.
Final Acceptance on November 24, 2017.
Discussion open until April 30, 2018.
DOI: 10.28927/SR.403291