What does tunnel lining mean? What does tunnel lining mean?

1, secondary lining is a term in tunnel construction. When the tunnel is excavated, it will advance along the tunnel face, and the four sides of the tunnel excavated later need to be reinforced. "Secondary lining" refers to the work that needs to be reinforced again around the tunnel.

2. The initial lining is fully stressed. When the deformation of surrounding rock is stable and the initial support is fully stressed, the secondary lining will be applied. This method is also the most popular theory and statement at this stage.

3. The primary lining and the secondary lining have the same stress, which is based on the extremely high surrounding rock pressure and the special treatment of some special surrounding rocks.

4. According to the profound meaning of NATM, it is generally necessary to wait until the deformation of surrounding rock is completed before applying secondary lining.