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Título

NEW METHODOLOGIES FOR THE DETERMINATION OF THE YIELD PRESSURE OF MARINE CLAYS THROUGH THE CPTU

Resumo

The paper deals with the use of empirical formulas for the determination of the yield pressure of marine clays through the CPTU, considering their geological history, as recommended by Demers and Lerouiel (2002) and more recently by Mayne (2017), stating the need of adjustments of the empirical factors for each "geomaterial".
One of these formulas is by Kulhawy and Mayne (1990), which has already been the subject of analysis by the author (Massad, 2010), who proposed a methodology for the determination of its empirical factor for soils with a known stress history and with cone resistance (qt) varying linearly with depth. These conditions have been observed in marine clays in Brazil and abroad.
In the present work the author extends this methodology to two other formulas of Mayne (2017), which make use of qt, pore water pressure (u2) and hydrostatic pressure (uo), adjusting the empirical factors for cases of linear relationships of qt and u2 with depth.
The paper shows two successful cases of application to marine clays, in which the results of CPTUs and laboratory tests were available, as well as knowledge about the geological history of the soils.

References:
Demers, D. and S. Leroueil. (2002). Evaluation of Preconsolidation Pressure and the Overconsolidation Ratio from Piezocone Tests of Clay Deposits in Quebec. Canadian Geotechnical Journal, Vol. 39 (1): 174–192.
Kulhaway, F. H. & Mayne, P. N. (1990). Manual on Estimating Soil Properties for Foundation Design. Report EL-6800, Electric Power Research Institute, Palo Alto.
Massad, F. (2010). Nova proposta para a estimativa das pressões de pre-adensamento de argilas marinhas com base no CPTU. Anais do XV COBRAMSEG, Gramado, RS, Brasil. 2010.
Mayne, P. W. (2017). Stress history of soils from cone penetration tests. In: 34th Manual Rocha Lecture, Soils and Rocks, v. 40, p. 203-218. 2017.

Palavras-chave

yield pressure, CPTU, marine clays

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