Permafrost

Cooling effect of crushed rock revetment in permafrost regions
Zhi-zhong Sun, Wei Ma, Dong-qing Li
(State Key Laboratory of Frozen Soil Engineering, CAREERI, CAS, Lanzhou Gansu 730000, China)
Abstract: During the year of 2003-2005, an experimental embankment was constructed in
Beiluhe, the Qinghai-Tibet Plateau, using coarse (7-12cm), poorly graded crushed rock fill
material on the slope of the conventional embankment with thick ground ice permafrost
foundation, which should be called the crushed rock revetment embankment (CRRE). The
highly permeable CRRE installation was designed to test the cooling effect of CRRE concept
with conventional control embankment in an actual railway project. Using thermistor sensor
strings, ground temperature data were collected from test sections. At present study, based on
the ground temperature data measured in the boreholes within the CRSPE and conventional
embankments, it is found that crushed rock layer can take effect of reducing slope surface
annual mean temperature and slope surface annual range of temperature. Comparing with the
conventional embankment, crushed rock revetment has mainly the effect of heat insulation in
summer but is disadvantageous to heat losing in winter. According to rising of artificial
permafrost table and decreasing range of ground temperature and difference of deformation, the
heat stability of CRRE is better than that of the conventional embankment. It will be a long
term process for crushed rock revetment to adjust the interior temperature field of embankment,
so it is careful when using the measure in the Qinghai-Tibet Railway.
Key words: Qinghai-Tibet Railway, permafrost; cooling effect, crushed rock revetment
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