| dc.description.abstract | ABSTRACT
Researches have suggested that slip rates can significantly influence the
strength of the slip zones of landslides, and the effect of water on the slip zones is
also proposed as a crucial factor. Nevertheless, efficient reports on this process
are still limited and are continue being debated. In order to dig deeper into the
roles of slip rate and drainage condition on the strength of the slip zones of the
landslides, a series of rotary shear tests were conducted on a wide range of shear
velocity (from 10-7
to 1 m/s) with normal stress of 1 MPa on kaolinite clay. For
the control of radial drainage condition, samples were sandwiched by two
impermeable-holders and covered by a Teflon ring. The system then being
submerged into water tank. This research also assesses the correlation between
the friction characteristics and the temperature changes in the submerged
condition. The results illustrated that the steady-state friction coefficient reached
0.2 at a slip rate from 10-7 m/s to 10-5 m/s and followed by a slightly raised to 0.26
at 10-4 m/s, 0.3 at 10-3 m/s, and reached 0.4 at 10-2 m/s before dropping to 0.3 at
10-1
. The friction coefficient at 1 m/s shown the slip-weakening behavior with
steady-state friction equal 0.14, indicated that the submerged condition is different
to the dry and saturated conditions from previous studies. Temperature
measurement results during the tests were maintained at around 25 – 26 degrees
Celsius at a low slip rate (from 10-7 m/s to 10-3 m/s), then gradually increased to
32 degrees Celsius at 10-2 m/s, and significantly raised to 60 degrees Celsius at
10-1 m/s and 75 degrees Celsius at 1 m/s. However, this study proved that the
linear thermal expansion of kaolinite clay had been created by the shearing
process, not related to the changing of axial displacement.
Keywords: Rotary shear test, kaolinite, velocity dependency, drainage
condition, temperature measurement. | en_US |