Bearing capacity of monotonically installed tapered piles in medium-dense Fontainebleau sand

Overview & Synopsis

Tapered piles installation in medium-dense Fontainebleau sand and subsequent loading were performed in the geotechnical centrifuge at Gustave Eiffel University. The physical set-up include models of piles with three different shapes -straight profile (S), and two conical with taper angle of 0.70 degrees (T1), and 1.4 degrees (T2). The aim of the study was to identify the optimal pile shape with respect to installation and load-bearing capacity. After the monotonic installation the penetration depth and volume were the same for all pile models. Afterwards, the models were subjected to static load tests in compression, and then in tension. A considerable increase of shaft friction during installation was observed for T1 and T2 piles. At the end of the installation, the maximum average shaft resistance was about 6 and 8 times higher as compared to the S pile for the T1 and T2 models, respectively. The shaft friction in compression was higher for tapered models than cylindrical one. Larger peak values of shaft friction in tension were also noticed for tapered piles. Similar shaft friction in tension and compression was found for cylindrical pile. Contrary, the shaft friction ratio of tension to compression is about 0.33 and 0.14 for T1 and T2 piles, respectively.