Subway Line 18 site welcomes first shield machine

Tunneling of a segment of Guangzhou' s subway Line 18, between Air Shaft No.4 and Shield Shaft No.5, was recently finished by using a shield machine, the first time one has been put to work on the entire line.

Builders pose for a group photo before a background of the first shield machine used in the subway Line 18 project. [Photo/gznsnews.com.cn]

Subway Line 18 will be all underground and will run from Wanqingsha town to Guangzhou East Railway Station, spanning a total of 61.3 km.

It will have nine stations, a metro depot and a parking lot, and it is expected to reach speeds of 160 km per hour.

The 8.8 mdiameter big shield machine started tunneling on No.4 shaft in Nansha district, headed northward to No.5 shaft in Fanyu district for 1,862.5 meters.

The shield machine has successfully tunneled a segment of Guangzhou' s subway line 18. [Photo/gznsnews.com.cn]

The construction faced several difficulties because the segment goes through complex landforms including the Pearl River system and runs beneath building clusters and farmlands.

The toughest part is the Pearl River, where deep layersare softer than superficial ones, making engineering accidents more likely.

A great deal of jacking force was applied to guarantee security, even while builders gathered first-hand information about the project' s safety, quality and progress with the help of video surveillance.

Line 18 is now 30-percent complete.