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 invention belongs to the technical field of thermal protection of tunnels in permafrost regions, and relates to a method for promoting the thawing of surrounding rocks in the shallow buried sections of tunnels in permafrost regions and quickly forming frozen soil water-proof curtains in the surrounding rocks to ensure the structural safety of the shallow buried sections of tunnels. thermal protection technology, especially a method for active thermal protection of shallow buried sections of tunnels in permafrost regions with thermal rod groups; the protection effect of this method can be automatically monitored. Background technique [0002] In recent years, under the background of the development of the western region, the transportation industry, which is the basic and leading industry of the national economy, has developed in an all-round way. my country has also made preliminary achievements in tunnel construction technology in the permafrost re...

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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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