ABSTRACT
This project is to install a new station in the tunnel between operating stations. The new station is a two-story structure, with the existing subway tunnel of one level and two spans, widened on both sides to form a split platform, and a newly constructed concourse level on the second basement level due to shallow soil cover at 2.4 m. For the construction of the second basement concourse floor, underpinning was performed on a section of approximately 75 m. After the underpinning, lead-in shafts were excavated, and after driving underpinning piles using the BH (Boring Hole) method, the existing frame was underpinned. This project was successfully completed without affecting subway operation. This paper describes the removal of the sidewalls of the existing frame and underpinning work associated with the installation of a new station in the inter-station tunnel section.
