At 10 PM on August 2, the main line of the eastern section of Shanghai's North Cross Passage (Rehe Road–Shuangyang Road) opened for trial operation, marking that the 19.1-kilometer North Cross Passage, after a decade of construction, has finally achieved full-line opening.

The North Cross Passage is an east-west dedicated passage for passenger cars in the northern part of Shanghai's central urban area, serving medium- and long-distance traffic in key northern areas, and is an important capacity expansion and supplement to the northern line of the "Three Horizontal" routes. The North Cross Passage starts at Beihong Road in the west and ends at Neijiang Road in the east, running through the northern part of Shanghai's central urban area and passing through six administrative districts along its entire length. It is an important component of the backbone road network of Shanghai's central urban area and is also China's first super-large and ultra-long underground expressway in a core urban area.

During the decade of construction, the tunnel builders overcame difficulties and tackled key challenges, completing "impossible missions" and creating an "encyclopedia" of underground shield tunneling crossings. Over the ten years, the North Cross Passage crossed rail transit more than ten times, passed beneath hundreds of buildings of various types (including century-old heritage-protected buildings), and repeatedly crossed over and under the Suzhou Creek, setting multiple national records with one "extreme crossing" after another.

On the occasion of the tunnel's opening, major mainstream media across the city focused their coverage and cheered for the tunnel builders under the blue flag.

Western Section: Setting New Records, Filling Gaps

Creating an "Encyclopedia" of Underground Shield Tunneling Crossings

The tunnel environment of the western section of the North Cross Passage was complex, with a winding route. The main shield machine "Zongheng" had a diameter of 15.56 meters, the largest in Shanghai's history. During construction, the tunnel builders steered it through housing and buildings on a large scale, passed at close range beneath operating rail transit and the Suzhou Creek flood-control embankment multiple times, and completed a 500-meter-radius S-shaped sharp turn, the first in China and rare in the world.

During shield advancement, "Zongheng" made a "sharp-turn" crossing beneath the century-old heritage-protected Zhaofeng Villa complex, with all parameters of the soil and structures performing well and the ground loss rate only 0.2%. The "Zongheng" shield also "brushed past" Metro Lines 7 and 11, with the maximum deformation of the metro tunnel only 8 millimeters, setting a new world record in tunnel construction.

Eastern Section: Veterans Set Out, a Victorious Conclusion

Setting Multiple World Records in the Shield Engineering Field Again

In 2021, half a year after the western section of the North Cross Passage opened to traffic, the "Zongheng" shield steered by the tunnel builders was once again deployed. The tunnel of Section VIII of the eastern section has a total length of 2,842 meters. The tunnel builders steered the super-large shield to overcome multiple challenges, including launching under 7.78 meters of ultra-shallow cover, the first in China to push through a station horizontally within the shaft without disassembly, and passing beneath operating rail transit, setting multiple "China firsts" and "world firsts." In particular, during the crossing beneath Metro Line 4, the tunnel builders overcame the technical difficulties of minimum clearance, maximum gradient, sharpest curve, and minimum angle in one go, successfully completing the tunneling target for the running tunnel and proving their "absolute strength" in the underground engineering field with solid engineering results.

During construction, the tunnel builders also independently developed an "electro-osmosis detection system" to effectively solve excavation challenges in soft-soil areas; developed an unmanned monitoring system for deep foundation pits to ensure the safety of pit excavation; and pioneered fair-faced concrete without decorative finishing, enabling exposed simple installation of electromechanical equipment and leading a new trend of low-carbon energy conservation...

Digital Empowerment of Project Construction

Creating a Model of Informatized and Intelligent Major Engineering

Pioneering Digital-Intelligent Innovation for Mega Tunnels

During the construction of the North Cross Passage, there was no precedent for the complete BIM design and application of a mega tunnel. Tunnel Engineering Co., Ltd. (STEC) took the lead in carrying the concepts of refined design and digital delivery throughout the North Cross Passage project.

From the early integration of above-ground and underground 3D data to ensure the optimal project siting; to fully using BIM technology during construction to play a "supporting role" in project construction, making project costs better, impacts lower, and quality better; and then in the later stage, using the digital results from the construction period of the North Cross Passage as a cornerstone to deeply explore digital completion and delivery, making construction more efficient and operation and maintenance more refined.

The "Tunnel Premiere" of Unmanned Paving

In the road paving of the North Cross Passage, STEC took the lead in applying unmanned paving technology. Through intelligent asphalt road construction equipment and a complete set of technologies, workers no longer need to stay in the cab; they only need to send instructions, and with the equipment's powerful back-end computing capability, the work can be completed, achieving a "dazzling transformation" of road paving technology.

During construction, STEC also used a ground-based augmentation Beidou satellite positioning and navigation system. Through a large number of sensors installed on intelligent equipment, it fully collected and analyzed data such as ambient temperature, road surface temperature, and rolling speed gathered during construction, achieving real-time dynamic monitoring and early-warning handling of road surface data. "Intelligent" paving, while achieving refined control of road construction, also ensured the quality of road paving.

Opening a New Chapter in Smart Operation and Maintenance with a Full Life-Cycle Concept

In terms of smart operation and maintenance, STEC will address the characteristics of the North Cross Passage—"long distance, narrow lanes, low space"—by using a full life-cycle operation concept and digital operation and maintenance technology to tackle difficulties and pain points one by one, creating an intelligent, safe, and green STEC operation and maintenance model.

Artificial intelligence will replace traditional inspection and supervision. Through intelligent IoT devices, an intelligent situational awareness system for the North Cross Passage will be built, and a full life-cycle management and maintenance platform will be established to fully realize online intelligent management while enhancing the tunnel's emergency rescue capability. Various sensors will be deployed to monitor the air quality inside the tunnel in real time, making the travel environment of the ultra-long tunnel greener, safer, and more environmentally friendly.