Permafrost

initial thermal erosion. The research indicates that: (1) melt belt would exist not less than ten
years when the temperature of initial thermal erosion was positive temperature, which will
become hidden trouble of embankment through the long-term working; (2) whereas, when the
temperature of initial thermal erosion was negative temperature, permafrost table ascend 6~10m
in the first three years, and the disappearance time of melt belt was 10 yeas ahead of scheduled
comparing with the normal construction method; (3) the effect of initial thermal erosion of
negative temperature did not linearly increase with the temperature descending, and the lower
negative temperature was not easy realized, therefore, the suggestion best temperature during
construction was -1℃. In conclusion, the temperature field of embankment under the conjunct
effect of air temperature and ground temperature will come into beneficial circulation in the
condition that initial thermal erosion was negative temperature; accordingly, long-term stability
of high-filling embankment can be safeguarded effectively.
Key words: initial thermal erosion; high-filling embankment; permafrost table; melt belt
34
In-situ study on cooling effect of two-phase closed thermosyphon &
insulation combinational roadbed
Junjie Wu,Wei Ma
(State Key Laboratory of Frozen Soil Engineering, CAREERI,CAS, Lanzhou Gansu 730000, China)
Abstract: In 2003, a new testing roadbed—two-phase closed thermosyphon & insulation
combinational roadbed was built in Beiluhe region, which lies in the hinterland of
Qinghai-Tibet plateau. By analyzing the ground temperature of the testing roadbed, we make
some conclusions below. Firstly, the thermosyphons worked consecutively from around
October 10 th to about March 1 st in the first year, and they worked possibly at later proper time.
Secondly, if we choose -2 isotherm as the boundary of the cooling effect, the effective radius
of these thermosyphons is 1.92m in the east slope and, 2.12m in the west slope. Finally, the
combinational configuration makes the roadbed keep a very low ground temperature, so it is a
very successful roadbed configuration for the high-temperature permafrost.
Key words: permafrost; two-phase closed thermosyphon; insulation
Selecting an Appropriate Type of Basement in Regions with
Complicated Permafrost Conditions
(an example for north of Western Siberia)
K. Baldunova
(Lomonosov Moscow State University, Geographical faculty, Department of Cryolithology and Glaciology)
Abstract: Western Siberia is a strategically important region of Russia. Analyzing natural
conditions, 4 regions differing in permafrost conditions could be selected of oil-and-gas
provinces, localized in permafrost area of Western Siberia. They are as follows: Yamal, Tar