The paper presents the results of two extensive research programmes on shallow and deep foundations installed near slopes. Two approaches are combined in these studies: physical modeling in the LCPC geotechnical centrifuge and FEM analyzing using the CESAR-LCPC code. The first part of the paper deals with the bearing capacity of strip or rectangular footings installed near slopes and supporting inclined and/or eccentric loads. Results obtained by both experimental and numerical approaches and compared and new rules are proposed to take account the slope effects on the bearing capacity. The second part of the paper presents an experimental study of piles installed in slopes and subjected to lateral loads. Horizontally loaded piles are usually designed by p-y curve methods. The aim of the programme is to determine coefficients that should be applied to the p-y curves of the reference pile (installed in flat ground) to take into account the presence of the slope. Soil reaction p and pile displacement y are derived from the bending moments measured on the piles during loading. The responses of the reference pile and of piles installed at different distances from the slope are compared and coefficients are proposed for practical applications.
The proximity of slopes has a strong effect on the response of shallow and deep foundations. Most of the current codes propose to design foundations near a slope in two steps. The bearing capacity and the settlement are first calculated assuming that the same foundation is resting on flat ground (reference foundation). Then, the effect of the slope is taken into account applying multipliers or reduction coefficients to the computed values. The first step is easily done from laboratory or in-situ test results and all codes of practice indicate the procedure to design the reference footing.
