A 8m thick layer of medium sand overlies a deep deposit of dense gravel. A series of standard penetration tests carried out through the depth of the sand has established that the average blow count is 26. Further tests show that the gravel has a standard penetration value of N = 52 in the region of the interface with the sand. A precast pile of diameter 300mm is to be driven down through the sand and to penetrate sufficiently into the gravel to give good end bearing. Adopting a safety factor of 3.0, determine the allowable load that the pile will be able to carry.
given that,
Average blow count
diameter of forecast file
standard penetration value (N)
factor of safety(fs)
length of file
allowable load
Qu
where,
gross sectional area
i.e
(Q)
lateral surface area
i.e, dia of file length of file
(Q)
Qu
Qu
allowabe load
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