China News Service, Beijing, January 10th (Reporter Wei Xi) On January 10th, the North Extension Project of Tongjing Road in Suzhou City, which was surveyed and designed by the Fifth Survey and Design Institute of China Railway, completed the most difficult “traversal” in urban tunnel history on the 9th. Journey"-the large-diameter shield machine smoothly traversed the Shanghai-Nanjing intercity high-speed rail at a speed of 350 kilometers per hour.

　　Process inspection data showed that the cumulative settlement did not exceed 1 mm. This is the first “hardest case” in the world’s construction and construction history where a large shield machine traverses an operating high-speed rail, and it is also an inspiration to cover design, construction, Successful cases of equipment manufacturing "package" programs.

　　The project is located about 2.1 kilometers west of Suzhou Railway Station, with a total length of 2,490 meters. It is a north-south "Duotou Road" in the central city of Suzhou that is planned to be opened during the "13th Five-Year Plan" period.

　　This is the longest north-south main road crossing the city, but it has become a difficult "slot" in Suzhou's north-south communication for ten years.

The main reason is that opening up this road faces major risk points such as crossing Wanshun Tower, Baoen Temple and other ancient buildings, as well as the Shantang River and the running Shanghai-Nanjing intercity high-speed railway, Beijing-Shanghai railway, Beihuan Expressway and other major risk points. Concentrated in a short distance of more than 400 meters-shield tunneling, 30 meters sideways through the Wanshun Building and other cultural preservation buildings, 118 meters down the mountain and pond river, these are the top difficulty in the history of construction.

　　More importantly, 305 meters ahead of the project is the Shanghai-Nanjing intercity high-speed rail, one of China's busiest high-speed rail lines. The high-speed rail swiftly passes by every 3 minutes, and the slightest deviation will cause disastrous consequences.

　　Since February 2017, China Railway Fifth Survey and Design Institute has planned and fully promoted the north extension project of Tongjing Road, and has cooperated with many units to carry out technical research.

The north extension project of Tongjing Road uses a large-section mud water shield with a diameter of 13.25 meters to underpass the Shanghai-Nanjing high-speed rail bridge, while the current underpass high-speed rail bridges in China are shield tunnels with a diameter of about 6 meters.

To adopt large-diameter under-crossing high-speed rail bridges, first determine the optimal under-crossing position.

Tongjing Road is located in the center of the old city of Suzhou. There are many control buildings on both sides of Shantang River Scenic Area, the traffic organization is complicated, the connection is difficult, and the tunnel route plan has many control factors. It can be said to be a "dojo in a shell".

　　At the same time, the working space under the high-speed railway bridge is only 4 meters, and a 30-meter-long isolation pile must be buried at a clear height of 4 meters to ensure the passage of the large shield. There has been no similar construction technology case at home and abroad before.

The Fifth Railway Institute set up a research team to carry out theoretical model research, new structural design, precise construction control and full-process risk prevention and control research, and innovatively developed the "low headroom full set of pipe cast-in-place pile machine" and related technologies, filling the gap in domestic and foreign construction technology .

　　Finally, after more than ten times before and after the project team has docked with management units such as railways, planning, roads, environmental protection, cultural relics, electric power, rivers, etc., after optimizing and selecting multiple options, the shallow shield tunnel program was used to open short distances and deep The shallow "road through" was finalized.

　　On January 9th, at the construction site of the north extension project of Tongjing Road passing through the Shanghai-Nanjing Intercity, many domestic industry experts and scholars witnessed the last isolation pile being drilled under the Shanghai-Nanjing Intercity Bridge, and the large-diameter shield on the left line The tunnel has successfully passed under the Shanghai-Nanjing Intercity, and the process test data shows that the cumulative settlement is less than 1 millimeter, marking that the most difficult node of the "broken road" that has been blocked in Suzhou for ten years has been opened.

　　The project is scheduled to be completed and opened to traffic in 2022, which will greatly improve the regional traffic conditions in Gusu for the millennium.

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