After the world's longest undersea high-speed rail tunnel shield machine“Dinghai”After the domineering appearance of China Railway Construction Heavy Industry。February 26，The other is jointly built by China Railway Construction Heavy Industry and China Railway 14th Bureau.“Ruilong”——Super large diameter shield machine“Yongzhou”Offline in Changsha, Hunan，It is also used in the world's longest undersea high-speed railway tunnel.——Jintang Submarine Tunnel of Ningbo-Zhoushan Railway。

“Yongzhou”Excavation diameter of cutter head of shield machine 14.57 meters，The total length is 135 meters，Total weight 4350 tons，Equipped with 308 special cutters，Reaching the world's first-class level as a whole。Shield machine cutter head coating“Ruilong”“Xiangyun”Pattern，It means that the builders start the shield crossing the sea with the auspicious spirit of the dragon and the heroic spirit of breaking through all difficulties.。

“Yongzhou”Get off the production line of China Railway Construction Heavy Industry

It is understood that，Jintang Submarine Tunnel is the key control project of Yongzhou Railway.，From Yinzhou District of Ningbo City in the west，East to Jintang Town, Zhoushan City，Total length 16.18 kilometers，Wherein the length of the shield section is 11.2 kilometers，Maximum buried depth: 78m，The tunnel passes through the 100,000-ton Jintang main channel.，Two shield machines are used from Ningbo、Driving in opposite directions from Zhoushan，Finally, the docking is realized on the seabed.，The required accuracy is not more than 20 mm.，Less than the diameter of a five-cent coin.，For the first time in the world, the super-large diameter shield machine was docked and dismantled on the seabed.。

Starting from the working well at the Ningbo end“Yongzhou”，A single excavation of 4940 meters will be made.，Not only through 23 oil pipelines、Ground buildings、Seawall、Wharf、42 risk sources such as the main channel，More importantly, it has to face the complex strata and marine environment.，Hard rock and soft and hard uneven strata account for nearly 70 percent，Maximum strength of 200 MPa。There will be 14 soft times in the interval.、Alternate transformation of hard formation，The long-distance crossing with great differences requires frequent high-pressure tool changing operations at a depth of 70 meters.，Complexity of construction、The difficulty and risk are unique in the world.。

“Yongzhou”Tunneling route diagram

In view of the complex construction characteristics of subsea tunnel,，The R & D team of Railway Construction Heavy Industry has carried out a number of innovative designs for the shield machine.，Heavy-duty pressurized cutterhead design，Compared with the conventional cutter head, 70 hob cutters are added.，Increase the weight by more than 100 tons，Reduce knife spacing、Increase the number of hob，Research and application of hob wear intelligent monitoring system，Wear resistance of cutter head、Rock breaking ability is stronger，And ensure that tunneling work efficiency。Among，The shield machine is applied with high control precision、Technologically advanced guidance system as tunneling equipment“ Eye ”，It is equipped with special equipment for advanced geological prediction and advanced grouting reinforcement.，It can detect and reinforce the unfavorable geology in front of the shield tunneling machine in advance.，To ensure the accuracy and safety of docking in the sea。

It is reported that，The total length of Yongzhou Railway Project is about 77 kilometers.，The design speed is 250 kilometers per hour，It is to build Zhejiang Province“One-hour traffic circle”，Form a convenient passenger transport corridor between the mainland and Zhoushan Island。After the completion of the project，It will fill the blank of the last district and city in Zhejiang Province without access to railways.，Effectively Promote the Development of Yongzhou City Integration，It is of far-reaching significance to speed up the construction of Ningbo metropolitan area.。