Abstract:

If the surrounding rocks of asymmetricalloaded and shallowburied tunnel are weathered, collapse often occurs. It is difficult to reserve deformation. The deformation of primary support is large. The 6step CD method, 3step primary invert method, temporary support strengthening method and backfilling method are adopted in the construction of the entrances of Jinlingtou tunnel and Tongyou tunnel on BeijingFuzhou railway. The deformations of surrounding rocks and primary supports are brought under effective control and the safety of the shield passing throught dangerous section is guaranteed. 

Key words: asymmetrical load, shallow bury, soft and weak surrounding rock, tunnel