Abstract: In order to address quality defects of lining voids, cracking or spalling that occur in operating tunnels, and based on the practices of casting concrete by lining jumbos on site, a conventional tunnel lining jumbo is renovated and new technology is proposed for grouting of the secondary lining with molds . The stubborn void defects existing in conventional secondary linings are solved by injecting the micro-expansion retarded mortar, characterized by good workability and early-strengthening, through an embedded RPC pipe, which improves the quality of the tunnel lining and provides a solid support for safe tunnel operation in the future.