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Engineering projects such as nuclear waste disposal and deep
tunnel under high mountain may invlove site condition of great
depth undergroud. As depth at considered site increases, both
the underground temperature and pressure tend to elevate. The
mechanical properties of rock at elevated temperatures and pre-
ssures can be significantly different from those which are in
the room temperature condition. Circumferential strain
controlled triaxial tests were perf- ormed to investigage the
influences of elevated temperature and pressure on the peak
strength, Poisson''s ratio, stiffness, and deformability of a
metamorphic quartzite. From experimental results, it is found
tha the peak strenth of the tested rock increases with rising
confinin pressure, and slightly decreases with increasing
temperature. With high conf- ining pressure, the decrease of
peak strength due to elevated temperature becomes more
significant possiblly derived from the higher thermal stresses
within the rock under high confining pr- essure. The stress-
strain curve appears steeper and the elastic modulus is higher
for higher confining pressure. The effect of elevated
temperature on the stress-strain curve, Poisson''s ratio,
elastic modulus, and the expansion stress are not concluded
from the ex- perimental results in this study.
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