A group of concrete piles (3×3) is driven into a uniform layerof medium dense sand, which has a unit weight of gt = AkN/m3and a friction angle of f = Bo. Thewater table is C m below the ground level. Each pile has a diameterof 400mm, a length of 10m. The centre-to-centre spacing of thepiles is s = D m.
Assume proper values for A, B, C and D.
- Calculate the ultimate vertical capacity of a single pile.
- Find the allowable load capacity of the pile group, based onindividual pile failure. Use a factor of safety of2.5 and a pile group efficiency of 0.9.
- Based on Hansen’s equations, find the allowable block capacityof the pile group. Use a factor of safety of 3.5.Assume the average unit weight of concrete piles is 25kN/m3.
