Preconsolidation pressure from piezocone tests in marine clays

Piezocone penetration tests were carried out at five sites in marine clay with overconsolidation ratios ranging from 1. 3 to 4.8. A simple model for the behaviour of these clays indicates that the effective vertical yield stress mobilized along the cone axis during penetration is equal to the difference between the actual induced total vertical stress in the soil and the total porewater pressure. The actual induced total vertical stress can be derived from piezocone test data. Theoretically the ratio of the vertical yield stress inferred from piezocone results and the preconsolidation pressure should correlate with the overconsolidation ratio. This hypothesis is supported by the field laboratory investigations presented in this study.Des essais de p\ue9n\ue9tration avec un piezocone ont \ue9t\ue9 effectu\ue9 sur cinq sites d'argile marine ayant des rapports de surconsolidation variant de 1,3 \ue0 4,8. Un mod\ue8le simple de comportement de ces argiles indique que la contrainte effective verticale \ue0 l'\ue9tat limite mobilis\ue9e durant la p\ue9n\ue9tration est \ue9gale \ue0 la diff\ue9rence entre la contrainte totale verticale et la pression interstitielle g\ue9n\ue9r\ue9es dans le sol. La contrainte totale verticale peut \ueatre d\ue9termin\ue9e \ue0 partir des r\ue9sultats des essais de piezocone. En th\ue9orie, le rapport de la contrainte verticale \ue0 l'\ue9tat limite, calcul\ue9e \ue0 partir des r\ue9sultats du piezocone, et de la pression de surconsolidation devrait \ueatre une fonction du rapport du surconsolidation. Cette hypoth\ue8se est v\ue9rifi\ue9e par les essais in situ et de laboratoire pr\ue9sent\ue9s dans cet article.Peer reviewed: YesNRC publication: Ye