Abstract:
The stress-deformation behaviour of any soil depends on a
number of factors including stress path followed during shear and
its mineralogical composition. In order to determine actual stressdeformation
behaviour of sands, it is desirable that the
composition of the specimen tested and the stress path followed
during the laboratory test are identical to those occuring in situ.
Sands are primarily composed of quartz. Mica is often present in
sands. A large portion of research on engineering behaviour of sand
has been concentrated on quartz and little attention has been paid
to the behaviour of micaceous sands. However, in many projects, it
becomes necessary to predict stress-deformation behaviour of
micaceous sands. This study presents thecresults of tests on a sand
containing various percentages of mica under different stress
paths')
Drained triaxial tests on sands containing different
percentages of mica along different stress paths are performed.
Results of these tests are presented herein. The mica content of
the samples tested are 2.5%, 4.0%, and 6.0%. The specimens are
tested at confining pressures of 55 kPa, 75 kPa, 100 kPa and 210
kPa.
using these test results, the effect of mica content on
maximum and minimum densities, maximum and minimum void ratios,
strength parameters, and volume change behaviour are studied. The
influence of stress path on the strength parameters and volume
change are also examined. It is observed that the maximum and
minimum densities of the samples decreases with increasing mica
content. conversely maximum and minimum void ratios increase with
mica content. Increasing mica content results in reduction of the
value of the angle of internal friction. It is also observed that
the angle of internal friction depends on stress path followed
during shear. The initial tangent modulus is found to increase with decreasing mica content. The initial tangent modulus is also found
to depend on stress path. Mica content has no influence on both
axial and volumetric strains. Both of these strains are found to
depend on stress path followed.
