The Behavior of a Foundation Laterally Loaded at the Top over Highly Porous and Collapsible Soil

In geotechnical engineering, the problem of laterally top-loaded piles occurs frequently. This type of foundation is often used in highly porous, collapsible soils, which are common in several regions of Brazil. Because of the limited information available in the literature, several load tests have been performed on piles subjected to this load. To analyze the behavior of piles in these collapsible soils, load tests were performed in steel piles (I), W 250 x 32.7 section (mm x kg/m), length 12 m, conventional bored piles (phi = 0.40 m; L = 12 m) and continuous helical auger piles (phi = 0.40 m; L = 12 m). All of them were tested at the same site. For each type of pile, a first load test was carried out with the soil in its natural condition of moisture content, followed by a second load test after the surface soil was flooded for 48 h. The results indicated a significant negative effect of flooding on the topsoil which consisted of sandy-silty clay with collapsible features down to the depth of 6 m. Load vs. horizontal displacement curves and soil coefficients of horizontal reaction were obtained. The results allowed the proposal of parameters for use in the soil under study. Before executing the load tests, laboratory and in-situ tests were performed to investigate the local subsoil.