Study On Forcasting Of Frost Damage And Antifreezing Strategies Of Tunnel In Cold Area

With the development of traffic basal constructions, lots of highway tunnels and railway tunnels appeared. The implementing nation policy of West-Exploitation made tunnel engineering extending to cold area where there is less of people, formidable natural conditions of high latitude and altitude. Compare with tunnels in common area, the construction of tunnels in cold area will face more complicated technic problems, especially the problem of freeze injury.The study on antifreezing of tunnels in cold area has important practical meaning, because there are a lot of tunnels in cold area in China. On the basis of investigating and analyzing lots of freeze injury and all kinds of frostresisting and antifreezing measurements applied throughout the world, this paper studied freezing damage mechanics of tunnels in cold area, analyzed causes of freezing damage of tunnels in cold area, and generalized the potential frost injury of tunnels in cold area, put forward comprehensive frostresisting and antifreezing measurements suitable to tunnels in China cold area.Taking Ri'erlangshan Tunnel Project as actual background, the thesis calculated the temperature field, frost force and thickness of insulation layer of the tunnel. Using the FEM method to calculate the temperature field fore and after the tunnel formatted, we get the maximum freezing depth of the tunnel is 1.8m. Introducing the result of the temperature field calculation to the stress field, we get the maximum frost force of the tunnel is 1.66MPa; the lining of the tunnel can bear the total action of the rock load and frost force. Finally, by calculating, the thickness of the polyurethane foam board is 5cm at the entrance of the tunnel, and 4cm at the inner part of the tunnel.The frostresisting and antifreezing measurements of tunnels in cold area mainly include the heat insulation method, the waterproof and draining method, the heating method and the structural protecting method. In specific, including the masking door, installation of the insulation layer, reinforcing the lining, strengthening the property of resisting freeze-thaw of the wall rock, heating the canal, insulation the exit, deeply burying the drainage cave etc.