Looking at the latest progress, the construction of airport connecting lines is accelerating
Recently, the construction of the third section of the urban railway airport connecting line, which was invested and constructed by Shanghai Shentie and undertaken by Shanghai Tunnel, has made new progress: the 14 meter super large shield tunneling machine "Jiyue" has been successfully received in the 2 # wind shaft. After the successful acceptance of the "Qiyue" in March last year, both of the three super large shield tunneling machines have completed the acceptance work, marking the smooth connection of the tunnel section from the 2 # air shaft to the Huajing Station, and also marking the complete connection of the three shield tunneling sections.
The third section of the airport connecting line project includes the starting shaft of the Meifu Road shield tunnel and the 3rd air shaft, with a total length of about 7.855 kilometers for the shield tunnel section. Among them, the total length of the section from Meifu Road working shaft to 3 # air shaft to 2 # air shaft tunnel is about 5.685 kilometers, and the total length of the shield tunnel from Huajing Station to Meifu Road working shaft is about 2.17 kilometers, which is excavated by two 14 meter super large shield tunneling machines, "Jiyue" and "Qiyue". The excavation diameter of the interval tunnel reaches 14.07 meters and adopts a single tunnel double track section layout.
Since its launch on October 21, 2022, the "Jiyue" shield tunneling machine has overcome difficulties such as complex construction environments and diverse geological types, and finally successfully completed acceptance at the 2 # wind shaft.
A major highlight of the "Jiyue" shield tunneling machine in excavation construction this time is its use of ultra large diameter shield synchronous pushing technology. It is understood that since the advent of mechanized shield tunneling construction technology, in order to ensure stable posture during shield tunneling, construction has been carried out alternately in a "series" manner of "pushing, stopping, and assembling". The synchronous push assembly technology used by the "Jiyue" shield tunneling machine this time successfully integrates the assembly of pipe segments into the excavation operation, connecting the excavation and assembly processes in parallel. While ensuring the stable excavation posture of the shield tunneling machine, the assembly machine achieves synchronous assembly of pipe segments, effectively improving construction efficiency. In the construction of the third section tunnel, the average operating time of the "Jiyue" shield tunneling machine in a single loop was shortened from 120 minutes in the traditional mode to 85 minutes, with the fastest record being only 61 minutes, an efficiency improvement of nearly 30%, which improved the efficiency of shield tunneling from "steady and fast" to "running all the way".
![Looking at the latest progress, the construction of airport connecting lines is accelerating](https://a5qu.com/upload/images/82f9d91ea751abba408223b4bc82ce3f.jpg)
In addition, the 2 # air shaft for shield tunneling reception is located in the area enclosed by the iron triangle, with the Li Shen connecting line to the east and the elevated section of the Shanghai Kunming high-speed railway to the west. During the receiving process, the tunnel door is prone to water and sand inrush, causing excessive surface deformation and railway track deformation, which affects train safety. In response to this situation, under the overall organization and early deployment of Shanghai Shentie, the project team, based on the experience of receiving the "Qiyue" shield tunneling machine, ultimately adopted the method of underwater reception, effectively reducing the probability of risk occurrence. With the joint efforts of all parties involved in the construction, the underwater reception of the shield tunneling machine only took 20 days, which is a 30% increase in reception efficiency compared to the "Qiyue" shield tunneling machine.
The airport connecting line has a total length of 68.6 kilometers and passes through three administrative regions: Minhang, Xuhui, and Pudong New Area. There are a total of 9 stations along the line, and the maximum operating speed of trains can reach 160 kilometers per hour. After the completion of the project, the operating time between the two comprehensive transportation hubs of Hongqiao and Pudong can be controlled at around 40 minutes, enabling transfer with multiple existing and under construction rail transit lines, facilitating the travel of citizens and passengers along the line. At the same time, it will further enhance the radiation effect of Pudong and Hongqiao comprehensive transportation hubs on the Yangtze River Delta region, serve the Yangtze River Delta urban agglomeration, and provide strong support for improving Shanghai's global urban level and core competitiveness, and implementing the national strategy of integrated development of the Yangtze River Delta.
Text: Li Jicheng
*Reprinted from official WeChat account released by Pudong
![Looking at the latest progress, the construction of airport connecting lines is accelerating](https://a5qu.com/upload/images/5ad61aaebb5484e3f7c9a09ed38c550b.jpg)