The project to build the second-phase port hinterland for the north container terminal at Busan New Port, which DL E&C is carrying out at Yokmang Mountain in Busan, has moved into full swing.
DL E&C said on the 4th that it has completed excavation of a tunnel that vertically penetrates Yokmang Mountain. It came seven months after excavation began in July last year.
The project to build the second-phase port hinterland for the north container terminal at Busan New Port uses rock generated by removing Yokmang Mountain to reclaim Busan New Port and Jinhae New Port, with completion targeted for 2034. It is the largest single project since Busan New Port opened in 2006. To achieve this, a peak as tall as a 43-story apartment building must be excavated to create a 120-meter vertical tunnel. The vertical tunnel serves as a passage for moving rock.
The project is being pursued as a turnkey method in which the builder performs all EPC (engineering, procurement and construction). Excavating a deep vertical tunnel more than 100 meters underground is considered a high-difficulty job. DL E&C proposed the RBM method to the Busan Port Authority (BPA), boosting both efficiency and safety at the work site.
An RBM is a large machine that drills through rock by rotating a head fitted with dozens of blades. Unlike the conventional method of digging down from the surface, this method drills a 0.3-meter-diameter hole at a depth of 120 meters, inserts the RBM into it, and excavates by rotating upward from below. The hole allows excavated rock to be discharged underground, eliminating the subsequent process of hoisting rock to the surface. This reduces the risk of fall accidents during construction and shortens the construction period by 30% compared with previous methods. Afterward, when a gantry crane—a large gate-shaped crane—equipped with a rotary drill passes through and bores it out, the vertical tunnel's diameter increases to up to 10 meters.
The key to this method is maintaining constant pressure on the RBM. If the pressure is too high, it can cause equipment failure, and if it is too low, excavation speed drops. Because the work requires dozens of repeated excavations, maintaining vertical alignment is also important.
Chief Executive Park Sang-shin of DL E&C said, "We are leading construction mechanization and technological advancement based on the technical know-how accumulated through numerous vertical tunnel projects, including the Yeongdong pumped-storage power plant and GTX-A," and added, "Through the RBM method, we will continue our 'overwhelming technology leadership' in the pumped-storage field."