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Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
direction is larger than the stress increment direction. However,
when the principal stress axes rotate along the stress paths of
AB and CD, corresponds to
α
σ
in ranges of [0°, 45°] and [90°,
135°], the directions of the strain increments are larger and the
non-coaxiality between the directions of the strain increment
and stress are induced.
Figure 6. Stress paths and strain increments in rotat
l shear tests at
N=1 and N=20.
ents an experimental investigation of drained
Leighton Buzzard sand in rotational
re subjected to cyclic rotation of principal
ncipal stress axes is mainly contractive. Most of the
rally non-coaxial, and the variation trend
tional shear continues,
. The larger the
Arthur, J. R. F, Koenders M. A. and Wong R. K. S. 1986. Anisotropy in
ociated with shearing in granular media. Acta
Mechanica, 64, 20-29.
Gut
nd Towhata I. 1991. Flow theory for sand
tress rotation in soils. Geotechnique, 33 (4), 355–383.
ng., Oslo, 231-237.
Nak
Hyodo M., Murata H. & Yasufuku N. 1998. Flow
anical and Geoenviromental Engineering.
Yan
Yu,
es of plasticity for granular materials.
D
A
C
B
D
A
C
B
D
A
C
B
D
A
C
B
D
A
C
B
D
A
C
iona
4 CONCLUSIONS
his paper pres
T
behaviour of saturated
shear. The samples we
stress axes while the magnitudes of mean stress and shear stress
were maintained constant. A special attention of the
investigation has been placed on the non-coaxiality of granular
soil subjected to the continuous rotation of major principal
stress axis at different stress ratios. The conclusions drawn are
as follows:
The volumetric strain induced by cyclic rotation of
pri
contractive volumetric strain occurs during the first
few cycles and its accumulation rate tends to decrease
as the number of cycles increases. The accumulated
volumetric strain increases with the increase in the
stress ratio.
The mechanical behaviour of sand under rotational
shear is gene
B
of the non-coaxiality degree shows an obvious
periodicity during the tests.
Lower degrees of non-coaxiality are observed in the
first few cycles. When the rota
the strain increment direction becomes closer to the
stress increment direction and higher degrees of non-
coaxiality are observed. The variation of the non-
coaxial degree appeared to be stabilized after
approximately 20 cycles of shearing.
It was also observed that the stress ratio has a
significant effect on the non-coaxiality
stress ratio, the lower degree of non-coaxiality
between the directions of the strain increment and
stress is induced.
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B
D
A
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