Permafrost

fact of the rising of artificial permafrost table, thermal regime, variation of soil temperature
with time, and thermal offset between upper and bottom of block stone layer is indicative of
some difference of cooling effectiveness for cold and warm permafrost regions. For cold
permafrost, block-stone embankment is effective for raising permafrost table and lowering the
soil temperature and a cool energy can be accumulated to makes the raising permafrost table be
gradually stabilized and thermal stability of permafrost beneath the BSE be gradually enforced.
For warm permafrost, block-stone embankment is effective for raising permafrost table but not
all effective for lowering the temperature. Soil temperature and thermal regime is basically
unchangeable with the application of block stone layer. The thermal offset between upper and
bottom of block stone layer shows that there is only a process of heat conduction in block stone
layer. Once raising permafrost table is affected by external thermal disturbance, artificial
permafrost table will be gradually dropped since the temperature near raising permafrost table
approaching to 0oC.Thus, a block stone embankment can be widely applied in cold permafrost
regions, but the application of block-stone embankment is worth discussing in warm permafrost
regions.
Keywords: Qinghai-Xizang Railway, Block stone embankment, cooling effect, monitoring.
Numerical Experiment and Analysis of Tensile Failure Process on Steel
Fiber Reinforced Concrete in low Temperature
Qin-yong Ma
(Department of Civil Engineering, Anhui University of Science and Technology, Huainan 232001, China,
E-mail:qyma@aust.edu.cn)
Abstract: In light of the tensile experiment of the SFRC at 0 , -5 , -10 , -15 , -20 , it was
discovered that the tensile strength of SFRC elevated as the temperature fell. Numerical tensile
model was established by means of the experiment result, and numerical simulation on tensile
failure process of the SFRC was prosecuted using RFPA2D, which was based on the finite
element theory and material failure arithmetic. The relationship curves of load force-load pace
and acoustic emission energy-load pace were gained and the numerical simulation result
resembles the experiment result.
Key words: Steel fiber reinforced concrete, Negative temperature, Tensile failure, Numerical
simulation, Acoustic emission
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