Permafrost

Problems of the further probing for a solution of a problem of stabilization of a roadbed and
contact-line supports on permafrost are stated.
Key words: permafrost, stabilization of a roadbed and contact-line supports
58
Skilled-experimental Check New Anti-frost Heaving Devices for
Supports of Contact Net and Aerial Lines on the
Transbaikalian Railway
V.G. Kondratiev, Z.B. Dashinimaev 1 , A.P. Balagansky 2 , V.V. Hananov 3
(TransEGEM, 1.Chita state university, 2.Transbaikalian railway, 3.JSC “Russian railways”)
Abstract: Supports of contact net and aerial lines of railways in the field of permafrost and
deep seasonal freezing of soil under impact frost heaving of soil are often deformed and lose
sustainability. It is necessary to repair them regularly. So, on the Transbaikalian railway for 10
years after end of electrification of the Trans-Siberian Railway it has been corrected and fixed
14676 and 3294 supports of contact net - 16,5% all supports on railroad are replaced. Only in
2004 it is corrected and fixed 2415 and 335 supports of contact net are replaced, on what 1196
windows in movement of trains by the general duration 2631,2 hours - 30% from duration of
year were required. In 2005 the amount of unstable supports again has essentially increased.
TransEGEM within 2001-2005 has executed development of technical decisions on provision
of sustainability of supports of contact net on permafrost, their skilled-experimental check on
Transbaikalian railway, also has developed recommendations on application anti-frost heaving
devices for supports of contact net on permafrost.
Anti-frost heaving device is executed in the form of built in a support thermosyphon, heat
and hydro insulation and anti-frost heaving bandage. The heat and hydro insulation is imposed
on soil surface around a support, covered from above by soil or turf. The anti-frost heaving
bandage consists of a protective sheath and nonfreezing lubricating grease. The elevated part of
a support is painted in reflective color.
At joint action thermosyphon and heat and hydro insulation in soil around support the roof
covering of a permafrost rises and thickness of seasonally-thawed soil is reduced. The anti-frost
heaving bandage protects a support from impact frost heaving in seasonally-thawed soil, and
painting of an elevated part of a support in reflective color reduces heating by solar rays and
corresponding transfer of heat to a soil, that also promotes reduction of depth of its seasonal
thawing. Forces of a bulging of a support in a seasonally-thawed soil as a result decrease and its
jamming in permafrost increases more thickly, that as a whole provides sustainability of the
support erected on permafrost.
In case of installation of a support with the anti-frost heaving devices on lots deep seasonal
freezing of soil in the beginning the long-term frozen ground, a layer seasonal freezing is
formed turns to a seasonally-thawed layer, and in the further interaction of a support with soil
occurs how is described above.
Key words: Permafrost, frost heaving, anti-frost heaving devices, thermosyphon, contact net
support, heat and hydro insulation