| Summary: | 碩士 === 國立中央大學 === 土木工程研究所 === 82 === An experimental study of the dynamic properties of Ottawa sand
and Ottawa sand treated with different levels of cement is
reported. The dynamic shear modulus, dynamic Young's modulus
and damping ratio of both Ottawa sand and Ottawa sand treated
with different levels of cement are determined by the Drnevich
Long-Tor resonant column device. The major parameters studied
are confining pressure, strain amplitude and treated level.
Increasing trends of both dynamic shear modulus and
corresponding unconfined compression strength show that soils
treated with cement can effectively improve the soil dynamic
properties during earthquake loading or the other dynamic
loading. Both dynamic shear modulus and dynamic Young's modulus
decrease with increasing the level of strain amplitude.
Instead, damping ratio increases with increasing the level of
stain amplitude. The maximum values of the dynamic shear
modulus for sand specimen occur at the shear strain amplitude
of 1.0×10-5 and the maximum Young's modulus of the sand can be
obtained at the axial strain amplitude of about 1.0×10-6 . The
maximum shear modulus of Ottawa sand treated with different
levels of cement is obtained at the shear strain amplitude of
1.0×10-6 and the dynamic Young's modulus occur at the axial
strain amplitude of 1.0×10-8. The effect of confining pressure
to the dynamic modulus of the treated sand decreases with an
increasing degrees of cementation, C%. The maximum dynamic
shear modulus and maximum dynamic Young's modulus of the
treated sand increase with an increasing degree of cementation,
however, the relationship of them is nonlinear. The rates of
increment of the dynamic modulus decrease with the increase of
degrees of cementation. The maximum dynamic modulus of Ottawa
sand treated with cement can be predicted by its unconfined
compression strength qu.
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