Shanghai rail transit will cross the Yangtze River for the first time, and the countdown has begun for the departure of the Shentong, a large shield train on the Chongming line

The Chongming line of Shanghai rail transit has made new progress. "Shentong", a large shield vehicle tailored for Chongming Line, has completed pre-assembly and officially entered the welding stage of the cutter head of the large shield vehicle. The welding period of the cutter head is about 25 days, and about 25% has been completed. This means that the Shentong has entered the countdown to departure.

In Shanghai's rail network, Chongming line is a relatively special presence. Except for Yu 'an Station (located on Chongming Island), the rest of the line is underground. The two sections, from Pudong to Changxing Island and from Changxing Island to Chongming Island, will set a record for the first time that Shanghai rail transit will traverse the Yangtze River in an all-underground form.

So, one may ask: where exactly is the city line tunnel under the Yangtze River being built? Is it possible to see water all around like a tunnel under the sea (river)? In fact, all the river crossings and tunnels in Shanghai are built under the water. For example, the tunnel between Yuyuan Station and Lujiazui station of Line 14 is buried more than 30 meters deep across the Huangpu River, and 37 meters deep when crossing the river.

In THE CROSS-RIVER SECTION OF CHONGMING LINE, TWO BIG shield VESSELS, "ShENTong" and "SHENTONG", WILL dig toward both ends of the line with Changxing Island as the center point. The Shentong, which arrived at the scene early and was ready for action, has a total length of more than 140 meters and a weight of more than 3,000 tons. Its cutter head is 13.5 meters in diameter, the height of a four-story building.

It took a lot of effort to get the big MAC from Guangzhou, where it was born, to Shanghai. The relevant person in charge of Shanghai Metro told reporters that the shield cutter head was first disassembled into 8 pieces in the factory, and then arrived in Shanghai through land and air transportation from Guangzhou, after a long journey, and finally assembled.

Not only the cutter head, but also the large pieces, such as the drive device and shield structure parts, are transported to the Changxing Island wharf in the same way, and then loaded and transported to the project site. Supporting equipment, trolley and other relatively small pieces are transported by land. "In the process of disassembly and assembly, it is necessary to strictly control the key links to ensure the safety and stability of the shield machine when it is put into use."

It IS REPORTED THAT THE SECTION TUNNEL TO BE CONSTRUCTED IN THE NEXT STAGE of "SHENTong" is about 7.74 kilometers in length, with a maximum buried depth of 34.3 meters, which will become the largest large-diameter mud-water balanced shield tunnel with the longest single tunneling distance in China.