Recently, the "Maglev No. 2" composite earth pressure balance shield machine, jointly developed by CRCHI and China Railway 14th Bureau for the Changsha Maglev East Extension Line, was successfully disassembled and lifted out, marking the double-line breakthrough of the world's first medium-low speed maglev tunnel constructed by shield method. The civil engineering works for the section from Maglev T2 Station to Maglev T3 Station on the Changsha Maglev East Extension Line have been successfully completed.

Breakthrough of the "Maglev No. 2" shield machine

The Changsha Maglev East Extension Line connecting to Terminal 3 has a total length of 4.454 kilometers and is the first shield tunneling undercrossing construction within the Huanghua International Airport area. The tunnel passes beneath airport aviation fuel pipelines six times and undercrosses the sensitive area of the airport runway glideslope for a long distance. The settlement control requirement for the glideslope sensitive area is ±10 millimeters, and the settlement control precision of shield construction directly affects aircraft takeoff and landing safety. At the same time, the shield machine needs to perform a small-radius secant launch of about 300 meters at the initial stage, which places extremely high demands on the configuration and adaptability of the shield machine. In addition, this project is the first application of shield tunneling method in maglev engineering, and the special mode of maglev transportation imposes higher requirements on tunnel construction.

To ensure smooth and controllable tunneling, CRCHI and China Railway 14th Bureau specially built two earth pressure balance shield machines tailored to the engineering geological and hydrological conditions and surrounding environment within the airport. They are the largest-diameter shield machines used in Changsha rail transit construction to date. The shield machines were designed with targeted features, adopting a composite cutterhead with an opening rate of 38%, optimizing the muck improvement system, improving muck discharge efficiency, reducing disturbance to surrounding strata, and ensuring construction progress. The settlement value of the shield machine undercrossing the airport sensitive area was only 0.2 millimeters, achieving "zero settlement undercrossing" and ensuring the smooth completion of the project.

Completed tunnel

In the future, once the Changsha Maglev East Extension Line project is completed and put into operation, the transfer time from Terminal 2 to Terminal 3 will be only 2 minutes. This will greatly meet the future collection and distribution needs of the airport and is of great significance for Changsha to build a comprehensive transportation hub centered on the airport.

Changsha Maglev Express in operation