TM 5-818-1 / AFM 88-3, Chap. 7
pz
=
effective overburden pressure at depth
where
=
base area
z
AB
φ
B
=
base diameter
=
effective angle of internal friction
=
0 for loose sand
qt
Arching develops at the base of piers in sand similar to
=
32,000 pounds per square foot for
qt
piers in clay; thus, the bottom 5 feet of shaft should not
medium sand
be included in the integration limits of the above
= 80,000 pounds per square foot for
qt
equations. The base resistance for a settlement of about
dense sand
1 inch can be computed from the following:
Qup =
AB
qt = 1.31 Bqt
(11-7)
0.6B
11-11
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