Abstract:

Comparison and contrast are made between the results of the conventional calculation method and those of the optimized calculation methods, which shows that the simple weight balancing method is neither the most rational nor the most economic means to cope with the sliding of the fixing supports in opencut inspection chambers under huge pushing forces, and on the contrary, the passive soil pressure of the surrounding soil mass can be fully used. Simplified structural loadbearing analysis, numerical analysis, insitu test data analysis and case histories demonstrate that, to some extent, the primary reinforcement and the secondary lining of mined tunnels can undertake the pushing force together and that fixing supports under huge pushing forces can be installed at the tunnel entrance when necessary countermeasures have been taken.

Key words: thermal pipes, inspection chamber, tunnel entrance, huge pushing force, fixing support, structural design