Abstract:

It is a worldwide inevitable trend to adopt probability limit state design method in the structure design. In order to promote the application of partial factor method in the structure design of highway tunnels, the authors make proposals on the partial factors, considering the characteristics of the tunnel structure and the partial factor method, as well as considering the tunnel construction method and the structure safety grade. The authors also make calibrations on these partial factors on basis of experiences. Conclusions drawn are as follows: 1) For tunnel structures with Grade I safety level, the total safety factor obtained by partial factor method is higher than that obtained by traditional design method; 2) For tunnel structures with Grade II safety level, the total safety factor obtained by partial factor method is almost the same as that obtained by traditional design method; 3) For tunnel structures with Grade III safety level, the total safety factor obtained by partial factor method is slightly lower than that obtained by traditional design method. The authors propose that the partial factor method based on reliability theory should be adopted in the new standards, specifications and codes. The paper can provide reference for the revision of the tunnel design standards in the future.

Key words: tunnel structure, calculation, reliability, partial factor