8.8-Meter-Diameter“Dream-Building”Shield Tunneling Machine Goes into Operation

The advent of spring brightens the whole of Beijing. At 11：06 of Feb.7, the 8.8-meter-diameter “Dream-Building” shield tunneling machine for the New Airport Line of Beijing went into operation in the shield-construction origination shaft at the northern side of Cigezhuang Station, marking an all-round tunneling for the construction of the New Airport Line and laying a good foundation for the successful completion of the shield construction and for an early turnover and track laying along the whole line.

The “Dream-Building” shield tunneling machine is a brand-new, high-performance, spoke-type earth pressure balance machine specially purchased to tunnel against long-distance and full cross-section thick gravel and cobble stratum. With the diameter of its cutter being 9.04 meters and the length of its main part being 11.9 meters, the machine is as long as 120 meters and weighs 1409 tons, and has been the largest machine possessed by UCD since shiled tunneling was firstly introduced for the construction of Subway Line 5 of Beijing, opening a new era for shield construction by UCD. Unlike the erstwhile 6-meter-diameter shield tunneling machine, the use of the 8.8-meter-diameter machine will become a new development trend for shiled tunneling construction of urban rapid rail transit system in China.

The first-stage civil engineering of the New Airport Line project undertaken by UCD is as long as 3 kilometers starting from Cigezhuang Station and ending at No. 1 interval wind well section, including the open-cut shield-construction origination shaft, shield interval tunnel and the No.1 interval wind well and reception well excavated openly and underground. The outer diameter of the tunnel segments of the interval shield tunnel is 8.8 meters, and the inner diameter is 7.9 meters, the loop width of the segments is 1.6 meters, all being general segments. To fulfil the task with high quality, the project department of the first-stage civil engineering of Tender 06 successfully brought the 8.8-meter-diameter tunnel segments to effect on the morning of Aug. 2, 2017, providing a powerful guarantee for the progress of the project.

Despite the tight schedule and the arduous task, all constrcution units made their best endeavors to give overall planning in advance and implemented the program to separate the stations from the shafts and the tunneling place from Cigezhuang Station, thus reducing mutual restraints and cross influences and laying a foundation for the early start of the shield tunneling. Since the entry in the construction site on June 3, 2017, the project management team of UCD has overcome lots of difficulties, such as influence from rain spell, winter period and other external factors, etc.and, by increasing resource input and implementing the construction continuously, the team has eventually realized the operation of the shield tunneling ahead of the Spring Festival. During the Spring Festival, the project personnel will hold fast to their work at the construction site and will spare no effort in ensuring the success of construction on all links of the project.

The New Airport Line of Beijing is a project that attracts social investment and is a line connecting the inner city areas with the New Airport. Identified as a rapid, direct and high-quality rail transit line, the New Airport Line targets a speed of 160 kilometers/hour, being the first in the urban rail transit industry in China. Powered by overhead contact networks, the line streches a total length of 41.36 kilometers, with the line underground being 23.65 kilometers and the surface elevated line and the subgrade section being 17.71 kilometers. Along the line there are 3 stations including North Airport Terminal Station, Cigezhuang Station and Caoqiao Station, 4 interval sections, 1 rail yard at Cigezhuang Station and 1 preserved parking lot.