Abstract: With the treatment of cracking on primary support of a of Shenzhen Metro as an example, the cracking causes are analyzed by means of numerical simulation. Meanwhile, according to the risk in the site, a integrated treatment including reinforcing the excavated tunnel, excavating balance of the remains, the secondary lining structure of the tunnel follows the excavation, following grouting under the foundation of building is proposed. In the end, the tunnel crosses the building safely. The paper can provide reference for similar projects in the future.

Key words: mined tunnel, primary support, cracking, secondary lining