OasisLMS

Enlarged Base foundations are one of the common foundation types used in structures subject to significant tensile forces in case of foundations for solar panels, transmission towers and off shore structures. In our previous research, we found that influence of geogrid reinforcement on uplift capacity of belled and belled wedge pile is independent of foundation geometry. Hence an attempt is made to investigate the axial and oblique pull-out behaviour of belled and belled wedge pile by modifying relative density foundation soil and geogrid configuration. In this experimental investigation total of 42 model tests were conducted in a model box with of size 1.2m x 0.75m x1.5m in homogeneous sand of two relative density 30% and 60%. In addition, the influence of geogrid inclination of 30?, 45? and 60? with reference to pile axis on uplift capacity of belled and belled wedge pile also studied. The model pile tests were performed by using belled pile with L/D of 7.5, belled wedge pile with taper angle of 2?, diameter (Db/Ds) ratio of 2 with three bell angles 30?, 45? and 60? and subjected to pullout loads of three inclinations as 0?, 30? & 45?. The tests results showed that with increase in relative density of soil, the axial and oblique pullout capacity of both belled and belled wedge pile has improved significantly. In addition, a comparative study is made for different configurations of geogrid reinforcement and found that the use of a single geogrid layer placed just above the belled and belled wedge pile with an inclination angle of 45 degrees gave more effective results than using the 30? and 60? inclined geo-grid.

Keywords: Belled pile, Relative density, Geogrid position, Axial and Oblique pullout loads, Embedment ratio (L/Ds), Reinforcement depth ratio (S/Ds), bell diameter ratio(Db/Ds)

Lakshmi V, Bangalore University; Raju KVSB, Bangalore University; Shashidhara E, Bangalore University; Virancha M, Bangalore University

International Conference Proceedings