Miniature pile drivers for centrifuge testing
Résumé
The use of centrifuge modeling offers another way for geotechnical engineers to investigate the loaded driven pile behaviors. It is well known that centrifuge tests take the place of in site tests to perform parametric studies useful to get a database for recommendations and to improve design codes. To accurately simulate loaded driven pile behavior, some conditions must be satisfied. A fundamental one is the checking of similitude laws linked to the pile behavior; the second concern an experimental aspect i.e. the installation of driven pile. To study and to fill these conditions, centrifuge pile hammers must be developed. A first difficulty is to conceive a miniature hammer supporting macro gravity effects and to achieve a model pile driving in flight. The paper describes the similitude laws linked to the driving of a pile and some of them have been already checked and validated during a pile driving centrifuge tests using a miniature pile driver. A recap of centrifuge pile drivers is proposed before to describe in details the last two pile drivers used the LCPC centrifuge. One has been developed to check similitude laws inherent to a pile driving ; a second miniature pile driver directly adapted on the top of the pile has been also tested. For both pile drivers, limits and performances of them are given and taking into account them, a concept of a new one pile driver is given able to drive and to load the model pile.