Method for conducting active thermal protection on tunnel shallow buried section in permafrost region using hot bar cluster

Abstract

A method for conducting active thermal protection on a tunnel shallow buried section in a permafrost region using a hot bar cluster comprises the following steps: collecting meteorological data in a tunnel site area; combining construction geological exploration data to ascertain the basic thermophysical parameters, permafrost types, superior limit depth, ground temperature annual mean changing depth and annual mean changing depth of the surrounding rocks in the tunnel shallow buried section; determining the burying range and the burying depth of the hot bar cluster, arranging the hot bars in an equilateral triangle mode, and determining the length of the hot bars according to the burying depth; and burying the hot bars by means of drilling insertion method, promoting the refreezing of the surrounding rocks in the hot-melt circle of the tunnel shallow buried section and the rapid forming of frozen earth seepage-proofing curtain in the tunnel surrounding rocks by means of the 'active' temperature-reduction property, that the hot bars can actively extract heat in the surrounding rocks out and send the heat into the atmosphere, of the hot bars, and conducting the thermal protection on the tunnel shallow buried section structure. The method for conducting the active thermal protection on the tunnel shallow buried section in the permafrost region using the hot bar cluster can accelerate the refreezing of the surrounding rocks in the hot-melt circle of the tunnel shallow buried section, shorten the freeze thawing circulation period and resolve the problems that the refreezing cycle of the surrounding rocks in the tunnel shallow buried section is long, a waterproof and drainage system is prone to becoming invalid and a freeze-thaw damage occurs in a supporting structure.

Description

Technical field [0001] The present invention belongs to the field of thermal protection technology in the tunnel of the frozen soil area for many years, involving a promotion of the shallow buried section of the tunnel of the frozen soil area for many years, and the rapid formation of frozen soil water separation curtains in the rocks around the caveThe thermal protection technology involves a method of active thermal protection for the shallow heat protection section of the frozen soil area tunnel with hot rod group; the protection effect of this method can be automatically monitored. Background technique [0002] In recent years, in the context of the development of the western region, the transportation business of the national economic foundation and leading industry has been fully developed. my country has also made preliminary achievements in the construction of tunnel construction technology in the Qinghai -Tibet Plateau for many years.During the "Twelfth Five -Year Plan" ...

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Problems solved by technology

However, there are still some problems. For example, the heat insulation layer has a retarding effect on the freezing back of the surrounding rock thermal thawing zone, and at the same time slows down the freezing speed of the surrounding rock in the thermal thawing zone in cold seasons, and it is easy to form layers on the outside of the support structure. Frozen soil with a network structure produces a certain degree of "segregation frost heave", which intensifies the degree of frost heave of the surrounding rock

[0007] 3) In terms of protection effect monitoring technology: the currently widely used in-cave monitoring technology is relatively mature, but there are also some shortcomings. For example, operations such as component embedding must be carried out at the same time as tunnel construction, which will inevitably cause damage to tunnel excavation, support, etc. The work causes certain interference; the monitoring equipment is easy to be damaged during the tunnel excavation operation; the pre-embedded pipe fittings of the monitoring equipment pass through the waterproof board of the tunnel, and water leakage is easy to occur; the monitoring device buried in the surrounding rock cannot be repaired after damage; the monitoring equipment must be installed In the limited space between the tunnel boundary and the lining, it is inconvenient to install and maintain

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