Volume 41, N. 2

May-August 2018

Assessment of the Stress History of Quaternary Clay from Piezocone Tests


Volume 41, N. 2, May-August 2018 | PDF (3 downloads)


This paper highlights the importance of linking regional geology to geotechnical ground investigation when estimating the pre-consolidation pressure σp of Quaternary clay deposits from piezocone tests. The work comprises a comprehensive site characterization from boring logs, piezocone tests and laboratory oedometer tests carried out at the Tubarão experimental testing site, in Southern Brazil. Geological characterization includes radiocarbon dating of samples from these clayey sediments. The approach developed at the testing site was later extended to 12 well characterized clay sites along the Brazilian coast to demonstrate that net cone penetration qt σv0 can provide reliable estimations of pre-consolidation pressure σp in Quaternary plastic, compressible, non-fissured clays. However, the σp/(qt σv0) ratio is not a constant (typically ranging from 0.1 to 0.4) and, as a consequence, pairwise parameter correlations considering σp and qt-sv0 lead to inaccurate predictions. Independent assessment of the void ratioe0is needed in order to produce more realistic first order estimates of σp from piezocone data.

Keywords: CPT, overconsolidation ratio, pre-consolidation pressure, stress history,

Submitted on July 05, 2017.
Final Acceptance on May 16, 2018.
Discussion open until December 31, 2018.
DOI: 10.28927/SR.412179