Cone Penetration Test and Pile Bearing Capacity Prediction.

A large number of full scale loading tests carried out mainly by the French Laboratoires des Ponts et Chaussees, has provided the experimental data necessary for verifying the validity of pile bearing capacity prediction methods based on the interpretation of the CPT and more precisely on the point resistance q//c. The loading tests concerned cast-in-situ, driven and even injected piles (under high-pressure) installed in a very wide range of soils. The cast-in-situ piles included simple bored piles, cased piles or bentonite bored piles. Driven piles included H-type steel piles and closed base tubes. Over half of the tested piles were equipped with extensometers for unit skin friction and point resistance measurement. The new prediction rules proposed, are based on an original soil classification according to the cone resistance q//c. They include tables making it possible according to the soil nature, its compactness, the type of pile and even the pile placement mehtod, to choose the appropriate values of alpha and k//c.