The author recently learned from Beijing Municipal Road & Bridge Group that the right tube of the shield-driven section of Contract Section 04 of the New Airport Line rail transit project has been successfully holed through, marking the first tunnel section of the New Airport Line to achieve breakthrough.
Contract Section 04 of the New Airport Line is 2.78 km long in total, with the first 600 meters in a sand layer and the remainder in a clay layer. Zhang Xinquan, project manager of the section, said that under such geological conditions, construction is generally not very difficult; a shield machine with a diameter of 8.8 meters can drive 2.78 km in a single long-distance excavation without intermediate maintenance or cutter replacement.
According to the introduction, the 8.8-meter-diameter shield machine is being used for the first time in the construction of the New Airport Line. The New Airport Line is 41.36 km long in total, of which the shield-driven section is about 16.15 km, more than one third of the total length. At present, there are 10 such shield machines across the entire New Airport Line.
It is understood that after the breakthrough of the right tube of Contract Section 04, the shield for the left tube will be launched in early April this year. It is expected that by the end of August this year, both tubes of Contract Section 04 will be holed through, and by the end of September, conditions will be ready for track laying. According to the construction schedule, the shield-driven section of the New Airport Line will achieve full breakthrough by the end of this year.