Some aspects of research and practice for pile design in France

Abstract

This paper summarises some aspects of the methods used in France for designing pile foundations under axial and transverse loadings. These methods mostly use the results of Ménard pressuremeter (MPM) tests and concern the determination of the bearing capacity, as well as the prediction of axial and transverse displacements. The prediction of the bearing capacity from CPT results is also given. After mentioning the general context of foundation design in France, the details of these methods are described and some of their experimental background is explained. These methods are now included in the French standard for pile design (published by AFNOR, Justification of geotechnical work-National application standards for the implementation of Eurocode 7-Deep foundations, 206, 2012), fully compatible with Eurocode 7 on 'Geotechnical design'.

Application of the ‘CPT 2012’ model of AFNOR standard for column design in Poland – Jazowa case study

“…The AFNOR NF P94-262:2012-07, revised due to Eurocode 7 recommendations [3], offers two pile calculation methods based on in-situ investigation, i.e., new pressuremeter model (PMT 2012) and new penetrometer model (CPT 2012), both fully compatible with Eurocode 7. The basic concept in new French standard is to distribute piles into 8 classes and 20 categories, see Table 1.…”

“…The unit shaft resistance expressed by equation 8has to fulfill condition of qs≤qsmax where qsmax is maxiumum pile unit shaft resistance (see Table 5). The calculated pile bearing capacity in compression Rc (or in tension Rt) is as follows [3,5]:…”

“…In AFNOR standard the design approach 2 and 'ground model' procedure is used. Consequently, the design value of pile resistance can be expressed as follows [3,5]:…”

“…The CMC columns drilled with full displacement auger correspond to pile class C3 and category 7, see Table 1. The soil layers are matched with those used in AFNOR (see Tables 2,3,4). Fig.…”

“…Classes and Categories of Piles[3,5] Bearing resistance factor kcmax for the 'CPT 2012' model[3,5] Values of installation factor α for 'CPT 2012' model[3,5] Determination of the a ,b, c parameters[3,5] Values of qs,max for 'CPT 2012' model[3,5] Model factor γRd values for 'CPT 2012' model[3,5] Calculated and design column resistance versus measured pile bearing capacity…”