1. Bearing capacity of Piles in group By: Alka Shah Assistant professor Civil Department Nirma University

2. Plie Group

3. Generally Qug ≠ n Qu Qug = ultimate load capacity of pile group n = number of piles in group

4.  But soil between the individual piles may become locked due to densification from driving and group may tend to behave as an equivalent single large pile  These tend to increase the group capacity to be greater then the sum of capacities of the individual piles

5.  Ultimate load carrying capacity of pile group is select as smaller of the two values determined from below two criteria: 1.Qug = n Qu 2.Qug = pile group as a equivalent single large pile (consider as a block)  Efficiency of pile group = g = Qug/n Qu Ultimate Load Carrying Capacity of Pile Group

6. Spacing of Piles 2.5 B to 3.5 B is preferable

7. Negative Skin Friction

10. Pile Group Settlement  In group of pile all pile set equally due to rigidity of pile cap  But settlement of group is more then the single pile due to stress zone  Pile group in clay fail due to settlement then the bearing pressure  Settlement of pile group is determine by assuming the entire pile group as an equivalent raft located at depth 2/3 D  Load distribution diagram is also shown  Width of raft = {B + 2 (1/4) * (2/3 D)}