In the construction of the underground railway in Taipei, an existing drainage culvert should be relocated. The new drainage culvert crosses underneath the existing Nankang RD. Pipe roofing method and precast RC box jacking method are adopted to build the new drainage culvert, so as to ensure the normal operation of the existing utility lines and the ground surface traffics. The length of the mentioned drainage culvert is about 22 m, with about 3 m overburden. A launching shaft is installed on one side of Nankang Rd, while an arriving shaft is installed on the other side of Nankang RD. 27 roof steel pipes (216×8 mm) are installed and cement grout (fc’=210 kg/cm2) is injected into the steel pipes, so as to provide advance support; then 22 precast RC boxes (2.1 m×2.4 m) are jacked from the launching shaft to form the box culvert. At last, the jacked precast RC boxes are connected and backfilling grouting is made. 