February 26，One cutter head painting“Ruilong”Super large diameter shield machine with pattern“Yongzhou”Off the line，Cutterhead excavation diameter 14.57 meters，It will be applied to the longest submarine high-speed railway tunnel in the world.——Construction of Ningbo End of Jintang Submarine Tunnel on Yongzhou-Zhoushan Railway。“Yongzhou”The shield machine is constructed by China Railway 14th Bureau Group、Joint R & D of China Railway Construction Heavy Industry Group，The total length is 135 meters，Total weight 4350 tons，Equipped with 308 special cutters，The assembly has reached the world's first-class level.。

Jintang Submarine Tunnel is one of the key control projects of Yongzhou Railway.，The tunnel starts from Yinzhou District of Ningbo City in the west.，East to Jintang Town, Dinghai District, Zhoushan City，Total length 16.18 kilometers，Wherein the length of the shield section is 11.2 kilometers，Maximum burial depth of 78 m。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.，The world's first super-large diameter shield machine will be docked and dismantled on the seabed.。

It is reported that，Starting from the working well at the Zhoushan end“Dinghai”The shield machine was successfully offline at the beginning of this year.，Starting from the working well at the Ningbo end“Yongzhou”Shield machine，A single excavation of 4940 meters will be made.。Staff introduction，In view of the complex construction characteristics of subsea tunnel,，The project team has made six innovative designs for the shield machine.，It is the first time in the world to develop and apply the intelligent monitoring system for hob wear.，Wear resistance of cutter head、Rock breaking ability is stronger，The tunneling efficiency is ensured.。

Yongzhou Railway is about 77 kilometers long.，The design speed is 250 kilometers per hour。