[ppt]bearing capacity from spt and plt - wordpress.com · web viewbearing capacity of piles in...
TRANSCRIPT
Plie Group
Generally Qug ≠ n QuQug = ultimate load capacity of pile groupn = number of piles in group
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
Ultimate load carrying capacity of pile group is select as smaller of the two values determined from below two criteria:
1. Qug = n Qu2. Qug = pile group as a equivalent single large pile (consider as a block)
Efficiency of pile group = 𝞰g = Qug/n Qu
Ultimate Load Carrying Capacity of Pile Group
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)}