February 1

Constructed by China Railway 14th Bureau Group

China's largest-diameter single-tube double-deck shield tunnel

has been successfully completed

This breakthrough

provides a successful case for connecting dead-end urban roads

while protecting ancient city relics and scenic spots

and developing and utilizing underground space

The receiving site of the "Heping" shield machine

Tunneling through Sheshan Mountain to open up a "dead-end road"

Sheshan Mountain in Wuchang is located on the east bank of the Yangtze River. It cuts off Heping Avenue at Zhongshan Road, turning it into a "dead-end road," which forces vehicles traveling from Zhongshan Road to Zhangzhidong Road to detour via Linjiang Avenue, adding 4.1 kilometers to the journey.

The Heping Avenue South Extension project uses a slurry balance shield machine with an excavation diameter of 16.03 meters, enabling a single-tube, six-lane tunnel that connects Heping Avenue to the north and Wujindi Road to the south. Once complete, vehicles traveling through the tunnel from Zhongshan Road to Zhangzhidong Road will take only 5 minutes, effectively easing traffic pressure in the east-west direction along the river in Wuchang and greatly improving urban traffic efficiency.

Rendering of the single-tube, bidirectional six-lane tunnel

However

opening up this "dead-end road"

is not easy

Difficulty 1: Crossing multiple risk sources

Workers operating a crane to install segment rings

Because the project is located in the urban core area, the tunnel boring process faces multiple major risk sources. The tunnel passes beneath the Wuchang Ancient City, the Beijing-Guangzhou Railway, and other areas. Along the route are more than 500 old buildings and several former residences of famous people.

Difficulty 2: Complex geological conditions

Completed tunnel

The geological conditions for shield tunneling are complex, including hard rock, mixed hard-soft strata, and karst cave areas, with a karst cave encounter rate as high as 40.5%. The maximum rock strength reaches 200 MPa, and the shield machine was stopped multiple times to replace cutting tools during tunneling.

Difficulty 3: Running parallel to an operating metro line

The horizontal distance from the operating Metro Line 5 tunnel is only 10 meters. Hard-rock shield tunneling is likely to disturb the completed Line 5 tunnel, making this one of the tunnels with higher technical content and difficulty in China.

In response to the above engineering characteristics, difficulties, and risk points, the large-diameter shield team of China Railway 14th Bureau Group leveraged its core technical advantages to carry out targeted design and optimization of the shield machine, and invited academicians and experts including Qian Qihu, academician of the Chinese Academy of Engineering, to provide guidance and review of the construction challenges.

Shield machine operator steering the shield machine forward

During tunneling, the construction team applied automated monitoring technology, installed observation points on sensitive buildings and structures along the route, monitored settlement data in real time, and adjusted tunneling parameters accordingly, achieving a safe and smooth crossing.

It is reported that the Wuhan Heping Avenue South Extension project is scheduled to be completed and opened to traffic by the end of 2023. It will effectively improve traffic conditions in the Wuchang Ancient City, ease traffic pressure on Zhongshan Road-Baishazhou Avenue, and form a key traffic corridor in the direction along the river in Wuchang.