Investigations on the dynamic behavior of a small-diameter pile driven in soft clay

This paper presents results and analyses of the dynamic behavior of a small-diameter pile driven in very soft clay, with its tip embedded to a depth of 4.5 m with a clear distance of 1-1.5 m above a stiffer substratum. The research program included static and dynamic load tests performed over a period of 15 days, with blows from three different drop heights. The dynamic signals were analyzed using two different pile-soil interaction models. The performance of the dynamic models in predicting the shaft and base behavior of the model pile, as well as the change in bearing capacity and in some model parameters the dynamic with time, are addressed in particular. Key words: dynamic pile tests, soft clay, soil models, set up. Cet article presente les resultats et analyses du comportement dynamique d'un pieu de faible diametre enfonce dans de l'argile tres molle, avec sa point a une profondeur de 4,5 m et a une distance libre de 1 a 1,5 m au-dessus d'une fondation plus dure. Le programme de recherche comportait des essais de chargement statiques et dynamiques effectues sur une periode 15 jours, et consistaient de coups de trois elevations de chute differentes. Les signaux dynamiques ont ete analyses a l'aide de deux modeles differents d'interaction pieu-sol. L'article discute de facon particuliere de la performance des modeles dynamiques pour predire le comportement de l'arbre et de la base du pieu modelise, ainsi que de la dynamique dans le temps de la capacite portante et d'autres parametres du modele. Mots-cles : essais dynamiques de pieux, argile molle, modeles de sol, installation. [Traduit par la Redaction]
Introduction Fine-grained soils exhibit time-dependent behavior, affecting their stress--strain response and shear strength. The most common processes are associated with water migration (consolidation), but other phenomena are also recognized, such [...]