Capacité portante de pieux isolés dans les argiles sensibles: étude de cas par la méthode pénétrométrique

The penetrometer test has been used to determine the bearing capacity of driven and jacked-in single piles in sensitive clays. The cases presented in this paper were carried out on two sites with steel, concrete, and wooden piles. The bearing capacities calculated on the basis of the results of penetrometer tests show that this approach has a good potential and at the same time is simple and fast. It has been possible to obtain a calibration by a comparison with the loading tests carried out on each of the piles. Taking into account the low strength of some of our clays, experience has to be gained in order to adapt the lateral unit friction curves to our clays. This approach also has the advantage of allowing the determination of the bearing capacity of wooden piles and of taking into account the conical effect when determining the lateral friction component. Key words: penetrometer test, piles, bearing capacity, cohesive soils, point resistance, lateral friction, steel, concrete, wood. [Journal translation]

Étude expérimentale de la capacité portante d'une couche de sol pulverulent d'épaisseur limitée

This paper presents a series of experimental measurements of the bearing capacity of spread foundations resting on a layer of sand of finite thickness; they are carried out using circular or rectangular laboratory models. After an analysis of the graphical expression of results illustrating the foundation–soil behaviour under the applied load, we study the relationships between the bearing capacity coefficient and the different parameters of the problem: relative thickness of the compressible layer, interfacial foundation–soil and soil–substratum conditions of friction, shape factor of the models.In every case, the results have been compared with available results of other authors and related with existing theoretical or semiempirical methods; these comparisons lead to the proposal of a rational testing procedure for determining the ultimate load for shallow foundations. Key words: foundations, bearing capacity, interfaces, scale effect, shape factor, bilayer.