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Investigation on the dynamic properties of saturated sand-tire chips mixture
by shaking table
Étude des propriétés dynamiques d'un mélange de sable saturé et de chute
de pneumatiques sur table vibrante
Bahadori H., Manafi S.
Urmia University, Iran
ABSTRACT: Liquefaction of saturated sands is one of the most important topics in geotechnical engineering.
Reinforcing saturated sands is one of the solutions to mitigate liquefaction potential. Scrap derived recycle materials
(such as tire chips and tire shreds) are some kinds of reinforcing materials. In addition to mitigation effects, the
reinforcing materials cause an improvement in dynamic properties of the soils. A series of one dimensional 1-g shaking
table model tests were conducted on sand and sand mixed tire chips. Firoozkuh sand No. 161 is used in this study. Four
different percentages of sand-tire chips were tested in this research. Shear modulus and damping ratio degradation curves
are presented in the hysteresis loops too. Results show that damping ratio increases with increasing tire chips content in
mixture. Also at the certain shear strain amplitude, shear modulus of reinforced soil decreases with increasing percentage
of tire chips.
RÉSUMÉ : La liquéfaction des sables saturés est l’un des sujets les plus importants en géotechnique. Le renforcement
des sables saturés est une solution pour atténuer le potentiel de liquéfaction. Des matériaux recyclés (tels que des copeaux
et des lambeaux de pneus) sont utilisés comme matériaux de renforcement. Outre l’effet d'atténuation, les matériaux de
renforcement amènent une amélioration des propriétés dynamiques des sols. Une série d'essais de chargement sur table
vibrante 1D ont été réalisés à 1g sur des mélanges de sable et de copeaux de pneus. Le sable Firoozkuh n ° 161 est utilisé
dans cette étude. Quatre différents pourcentages de copeaux de pneus ont été testés. Le module de cisaillement et
l'amortissement sont tirés des cycles d'hystérésis. Les résultats montrent que le taux d'amortissement augmente avec la
teneur en copeaux de pneus contenu dans le mélange. Également, à une certaine amplitude de déformation de
cisaillement, le module de cisaillement de sol renforcé diminue avec l’augmentation du pourcentage de copeaux de
pneus.
KEYWORDS: Tire chips, liquefaction, shaking table
1 INTRODUCTION
When saturated clean sand deposit is subjected to
seismic loading, the pore water pressure gradually
increases until liquefaction happens and settlement
occurs during and after an earthquake. The mentioned
problem is attributed to rearrangement of grains and
redistribution of voids within the soils. Over the years
many methods have been presented to increase
liquefaction resistance. However the main methods
utilized in liquefaction mitigation are classified as
densification, solidification, drainage and reinforcement
techniques (Ghiassian and Ghazi 2009). Utilizing tire
chips in soils is a kind of soil reinforcement which has a
wide range of application. Many research works have
been performed to achieve fundamental engineering
properties of soil- rubber mixture, such as compaction
characteristics, permeability, compressibility, modulus
of elasticity, and Poisson’s ratio. Feng and Sutter (2000)
conducted a series of resonant column test to obtain
shear modulus and damping ratio of sand reinforced
with rubber. They expressed that shear modulus and
damping ratio of the mixtures is strongly influenced by
the percentage of the rubber inclusion. Few studies have
been performed on the effect of adding tire chips in
mitigating the liquefaction potential of sand. Hyodo et
al. (2007) carried out undrained cyclic triaxial tests on
sand samples reinforced with tire chips. They found out
that tire chips control build-up of excess pore water
pressure of the mixture during shear. They obtained that
for sand fraction (i.e. sand volume /tire chips volume)
lower than 50 percent, liquefaction does not occur at all.
Studies on liquefaction resistance of reinforced soils
with tire chips have been so far limited to almost
element tests. In this paper a series of 1g shaking table
tests were carried out to investigate on the effect of tire
chips -sand mixture in reducing liquefaction potential,
settlements after earthquake and pore water generation.
2 SHAKING TABLE AND MATERIALS
2.1.
Model configuration and instrumentation
Figure 1 illustrates shaking table and its instruments.
Container is made of Plexiglas with inner dimensions of
200×50×70 cm. At bottom of the container a void
chamber is made by using a number 200 sieve (Bahadori
and Motamedi 2011). A plastic plate was rigidly fixed at
the center of container to separate reinforced and
unreinforced parts from each other and waterproofing
carefully. So two models (reinforced and unreinforced)
can be tested at once with the same input acceleration
(Uchimura et al. 2007).
