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s = 1 m
s = 5 m
s = 13 m
Fig. 9.7. Deformed mesh of the soil-pile-cap systemwiththe concentration of plastic
octahedral strains,for different positions
s = 9 m
(
s
=
1-13m
)
of the emerging fault rupture
neartheirmiddle.Noticethecompletelydifferentpatternofbendingmomentswith
depthbetweenfront-rowandback-rowpilesinFigure9.7:whereasforpile1(front
row) the maximum is at the top, for pile 6 (corner pile) the maximum appears at
10m depth. Evidently, such large bending moments, especially in the front row,
exceed the maximum conceivable capacity of a well-reinforced 1m diameter pile,
implying structural failure at least of conventional-type piles.
(3) For S
9m, the fault would have emerged near the right edge of the group in the
free-field. The piles with their presence and transmitted loads diffuse the rupture,
thereby suffering unequal settlements and nonuniform large displacements. As a
result,therotationandlateraldisplacementofthecapandthebendingmomentsin
the piles attain very large (unacceptable) values.
(4) Finally, for S
=
13m (free-field fault outcrop 3m beyond the pile cap), there is a
slight diversion of the rupture to the right with a simultaneous slight diffusion of
the plastic shear strains. Only the last row of piles is stressed significantly (max
M
=
2m). There is apparently no rotation of the pile cap, but a
downward and outward displacement are unavoidable; such displacements might
have a detrimental effect on a framed structure, one column of which is supported
on thestudied piled foundation.
≈
4MNmforh
=
